# Liquid cooling through home plumbing system



## Throwastone1990

Hey guys new member, I had this idea and just wanted the opinions of people with more experience then me.

Ill start off with I am a plumber by trade and work with boilers and liquid heating system. I would also like to add I build computers as a hobby though im still relatively new and have yet to build a liquid cooled rig, though I have researched it and understand how it's done. Keep in mind for me it is simple and cheap to add/move water lines not including the PC watercooling setup I could set this up in 1-2 hours

my plan is use a heat exchanger and connect my home plumbing to my PC cooling system in a attempt to remove the need for a rad, fan or even a reservoir. this is obviously ideal for fanless setups.

Assume there is a resevoir/pump combo inside the PC


to start the potable system or potable loop is the cold water supply line, the water that feeds your toilets and other fixtures. The domestic loop is your PC cooling IE CPU, GPU(s) what ever.

For green energy purposes I tied the return loop on the potable side right above the feed for the hot water tank, this means that the heated water will help supply the hotwater tank hopefully saving you on your hot water bill.

I was made aware that if the water is to cold it could cause condensation on my waterblocks, to overcome this I added a 1/2 line going from the return right above the heat exchanger to the supply, again right above the heat exchanger.( the pink pipe on the diagram) I can then use a globe valve so I am able to throttle the volume and can add as much heated water as needed to keep the coolant room temperature.

The only problem I can see is the water not circulating fast enough on the potable loop causing too much heat to build at the exchanger. I am kinda depending on the volume of water in the pipes along with proper pipe slope to keep the heat dissipated and the water circulating. Worst case scenario I have to find some sort of potable DC recirculating pump that uses low enough wattage to be able to hook up to a 3 pin fan plug. that could be difficult.


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## iinversion

Wow that sounds awesome to me. Of course, I know nothing of plumbing.

If you end up doing this definitely get us some pics.


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## Throwastone1990

well that's the issue i currently suffer, I live in Canada and I find it damn near impossible to find water blocks/ liquid cooling supplies from Canadian stores or sites, most of it I can rig up with work materials but the water blocks are a issue, especially cause im running two sapphire 7950's non reference. My next build hopefully two years from now I plan on trying a complete liquid cooled fan less set up. speaking of which do you need to liquid cool the MB, ram, SSD in a fanless rig?


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## bmgjet

Im not expert but ill share some of my opinions from past experience.

Your going to have trouble if your using tap water with impurity s. Iv ran a loop pump less just off the tap and dumping the water back down the sink when overclocking and a very cold night.
Cooling block ended up getting white paste stuff after a few nights use. A full time loop will have a lot worse problems.

Also running it back into the hot water cylinder feed line is hardly worth the effort.
The raise in water temp was only un-readable at idle, and under stress test still only raised water temp 4C.


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## iinversion

If you want it to be fanless you will need a VRM block for the mobo + CPU and GPU blocks. HDD/SSD cooling is not necessary and neither is RAM. You can do it, but it'd be for looks more than for performance.

Since your 7950's are non-reference and you are having trouble finding water blocks for them.. you could pick up some universal water blocks and then use some Enzotech copper heatsinks for the VRAM.


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## Throwastone1990

Ya I wasn't sure if it was worth running water back to the tank, I have limited experience when it comes to overclocking, mostly AMD catalyst and a few CPU settings in bios so I have no idea how much it will raise the water temp. I can run purified water or glycol in my PC loop if I want, the exchanger keeps the PC cooling loop and the potable loop separate, that's what we use them for when it comes to heating.

You used the water pressure to circulate your loop and kept adding water, I am keeping a closed loop system. I am just hoping the heated water will rise up the pipes and the heat will dissipate in the litres of water in my plumbing system, which will get refreshed every time someone uses water.

how well do those heatsinks work on Vram? cause I overclock that too. I have no problem waiting a couple of years for my next build. I feel like finding and installing a VRM block on my Mobo might be a pain in the ass but atleast I don't need to worry about the ram now.


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## iinversion

The heatsinks on the VRAM isn't just for overclocking, its to prevent them from getting too hot, period. They work as well as they need to work. I used them on some mining GPU's that I had AIO liquid coolers mounted to during the mining craze. Kept them from crashing due to memory overheating. They stick well too.

You probably don't need a VRM block either but since you want it fanless I'm not sure. Usually there's air flowing through the VRM heatsink either from case fans or CPU cooler fans..


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## bmgjet

My mistake. Didnt understand your diagram. I thought the heat exchanger would of been like a TEC cooling the water as it comes in to the loop. Then using the exit loop to cool the TEC.


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## Throwastone1990

@ BMJget

I just reread your post, when you had a 4 degree difference was it when you were running your test with tap water? if it was raising the water 4 degrees at the flow rate your tap would have that is huge, if I were to rig that up to a electric hot water tank it could save you 20 minutes recovery time pending the size of the tank. the savings would be decent if you game a decent amount, especially when people shower.

@inversion
I may look into your solution, got to do some more research but I still run into the problem of finding these parts, the reason I was going to wait for my next rig is I figured I would have to order them from the states. Thank you for the advice with the mobo cooling, I have a much better idea what i need to look for when buying one now. so what do you recommend for a powersupply? I figure there is no way to get a external powersupply that can put out the wattage needed for a gaming/OC PC, what would you recommend for a quiet/powerfull PSU?


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## iinversion

Quote:


> Originally Posted by *Throwastone1990*
> 
> @ BMJget
> 
> I just reread your post, when you had a 4 degree difference was it when you were running your test with tap water? if it was raising the water 4 degrees at the flow rate your tap would have that is huge, if I were to rig that up to a electric hot water tank it could save you 20 minutes recovery time pending the size of the tank. the savings would be decent if you game a decent amount, especially when people shower.
> 
> @inversion
> I may look into your solution, got to do some more research but I still run into the problem of finding these parts, the reason I was going to wait for my next rig is I figured I would have to order them from the states. Thank you for the advice with the mobo cooling, I have a much better idea what i need to look for when buying one now. so what do you recommend for a powersupply? I figure there is no way to get a external powersupply that can put out the wattage needed for a gaming/OC PC, what would you recommend for a quiet/powerfull PSU?


If you are looking for something quiet you can check out Be Quiet! DARK POWER PRO series or Fractal Newton R3 series.. What are the specs of the rig? Can tell you how much wattage you actually need. Quiet PSU's don't come cheap..

Ideally in the end of things you'd want to find a full cover waterblock, but if you can't then at least you have an alternative.


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## bmgjet

Had a needle valve off the tap to reduce flow rate down a lot. Never took a reading of how much it flowed but at a estimate it would of been filling a shot glass in about 10 secs. Since thats what I filled up to read the temp difference.

This was cooling 8350 at 1.57V 5.01ghz, 2X 7970 at 1.3V 1310mhz/1575mhz, VRM on motherboard. Pulled just over 950W at the wall.


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## bichael

Interesting idea!

I've no experiencing of water cooling as yet but I'm a HVAC engineer by trade so know a bit about heating and cooling systems...

Would it be possible to set it up something like a gravity boiler/cylinder system? The heat (from the PC in this case) then driving the water around the loop via convection? I would presume for that to work the cylinder would need to be at a higher level than the pc.

There would I'm sure be ways of calculating the buoyancy forces and working those against the expected pressure loss.

A few quick thoughts on flow rates:

- A shower might be say 15 l/min? So domestic pipe probably sized for around double that at maybe 2m/s? Sure you know this part better than me!

- Based on say 500W pc load and a 5oC temperature rise the required flow is 1.4 l/min (and roughly 1/5th of that when pc is idle)

- (A pc water cooling pump I think might be in the range of 500l/hour or 8.3 l/min but i suspect they may give this rating at a pretty low resistance? Not something I've ever looked in to.)

So you would be looking at design flowrates maybe 1/20th of those in a domestic system, so even with a standard sized domestic pipe you should be getting pretty low pressure loss (given pressure function of velocity^2). So would seem it could be feasible - but not really sure what the resulting temperatures might end up at though??

Be interested to see whatever you end up putting together!


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## u3b3rg33k

I've thought of doing this. I'd do it by putting a storage tank in front of my water heater with an HX in it (like in a remote boiler storage heater - the kind I have now), and then one of these in the PC to keep it isolated:
http://koolance.com/hxp-193-compact-plate-heat-exchanger

that way I can keep the PC gear all low pressure, and 100% of the energy (lets call it 100%, i know some leaks out) goes into reducing my oil bill. I'm paying for the electricity to run my PC, it might as well offset the hot water heating. And besides, a 40 gallon tank can heatsink a PC for HOURS, even with no draw.


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## Throwastone1990

@bichael

I am definitely going to try and use a convection current instead of a recirc pump on the potable loop. I plan on setting this up in my basement which would put the heat exchanger roughly a foot off the floor with the water lines being 7 feet higher on the bottom of the floor joists, I imagine the heated water rising and being replaced by sinking cooler water will create enough of a current i shouldnt need to pump it, only issue I could run into would be the water not moving fast enough causing the heat exchanger to be well above the room temp water I imagine will be running through it the majority of the time. will it get hot enough to be ineffective? probably not I really don't have enough OC or liquid cooling experience to say. I also didn't go as far as calculating flows, mostly because I have no idea what temperatures im working with, or how to calculate the conduction of heat in water circulating with a convection current in pexs pipe. I feel that standard plumbing pipe sizes is more then overkill for cooling one PC. Jesus leave it to a engineer to make a job more complicated then it needs to be









The plan is to use 3/4 pex pipe feed and return on the potable side of the heat exchanger, giving lots of volume to be heated, however im starting to think the water temperature isn't going to get as high as i expected, meaning that the 2 degrees it may raise the temp on the potable return will just conduct through the pipe and the sheer volume of water by the time it reaches the hot water tank making it kinda useless. I really need to see what temperatures im working with. The other issue is condensation on my water blocks. Generally the water in your lines is at or close to room temperature pending how the pipe's run. The majority of the time I will be cooling with 20 degree water, but for those rare times after using alot of water you may get water temps as low as 7 degrees. I originally thought I could just put a 1/2 pipe between the potable return and supply so i could preheat the water going into the heat exchanger a little bit, however if I am not getting enough of a temperature raise from the PC it may not be able to raise the water temp enough to avoid condensation. how to OC'ers generally avoid condensation with chiller units?

@u3b3rg33k
interesting idea, but the issue you will probably run into is that your return line from your boiler is going to be hotter then you want your PC to run at the water going through your boiler is probably 85 celc where you only want 20 - 30 also having a hard time understanding what you want to do but im imagining you are basically doing what I have in mind except before the hot water tank you want to have a preheat tank? how then would you cool the supply line enough between the boiler and the PC to actually cool the PC?

@iinversion
I have heard of those be quiet PSU's, like you said apparently really expensive. I feel like it may be worth going with a standard PSU and dealing with one fan. I have no idea what wattage the rig will be 2 years from now... any idea what single GPU's will be able to game at 4k 60+FPS and what wattage it will need


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## u3b3rg33k

Quote:


> Originally Posted by *Throwastone1990*
> 
> @u3b3rg33k
> interesting idea, but the issue you will probably run into is that your return line from your boiler is going to be hotter then you want your PC to run at the water going through your boiler is probably 85 celc where you only want 20 - 30 also having a hard time understanding what you want to do but im imagining you are basically doing what I have in mind except before the hot water tank you want to have a preheat tank? how then would you cool the supply line enough between the boiler and the PC to actually cool the PC?


I'd be heat sinking into 15-20C water, not 85C water. it would be in the potable water path, not the boiler system, so i'd be heatsinking into 40 gallons of cold water.


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## rcoolb2002

Maybe i just missed it, but how are you getting flow? Your house has pressure, but until someone opens a tap somewhere, there will be no flow.

Houses are typically at pretty high pressure compared to your PC system, so even if you drop pressure and have a surge tank, you will need a rather serious lift pump to get water back into the house plumbing.

I


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## iinversion

If you aren't buying a single GPU for another 2 years I can't tell you how much wattage you will need.

But today, on a non-AMD FX and non-i7 6 core+ CPU, you only need a quality 450W to power any single GPU configuration assuming you don't do insane overclocks and volt mod the GPU to the wall. If you end up using one of those other CPU's then you'd need to opt for 550W-650W(depending on config/overclocks) because they are a lot more power hungry.

This is single GPU configurations only and does not mean you can go buy a 7990(dual GPU card) for example and expect a 450W to power it and everything else. If you are looking to buy a PSU today I can give you several good recommendations.


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## bombastinator

OOOh! You sound like a perfect candidate to pull off my thermal gravity idea.

It's got a (giant) radiator but no pump or fans.

Basically you build an old fashioned 1930`s thermal gravity hot water system, where the furnace is a big box with the cpu on the bottom and the gpus stuck to the sides. You'd have to use a couple of fairly long pcie cables, and it would be ugly as hell, but you just hide it in a box and put the radiator (10 fin lightweight cast iron maybe. Get one for free out of someone's bathroom remodel)

There are people that collect radiators. Perhaps it might be worth doing if you come across a rare and particularly good looking one.

I'm thinking brass decorative toilet float for an air blast tank.


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## HyperC

Quote:


> Originally Posted by *rcoolb2002*
> 
> Maybe i just missed it, but how are you getting flow? Your house has pressure, but until someone opens a tap somewhere, there will be no flow.
> 
> Houses are typically at pretty high pressure compared to your PC system, so even if you drop pressure and have a surge tank, you will need a rather serious lift pump to get water back into the house plumbing.
> 
> I


Yes agreed you wont have flow unless you run the hot water.. I was a HVAC installer for almost 8 years and while the idea sounds good it will not work.. Remember that the water will not move until its used


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## Throwastone1990

@u3b3rg33k
your going to have to draw a diagram or somthing I am having a hard time imagining what your saying, sounds to me like you want to run your cold potable line right through your pc water cooling,you cant do that for multiple reasons biggest one being contamination from lead and other materials that are in the PC cooling supply the second being I don't think the fittings can handle the 60PSI your house is running at.

@rcoolb2002 and HyperC

if you guys read the initial post you would of seen i plan on using a heat exchanger to seperate the potable water from the PC cooling loop, meaning I can have two different pressures on both loops.

@hyperC The PC cooling loop will have a recirculating pump as for the potable side I am hoping either

a. through convection the heated water will create a cycle with the cold water. There is such systems in place in many buildings for hot water recirculation.

B. the roughly 30-50L of water in my plumbing system will absorb all the heat via conduction and therefore the loop cycling on the potable side is pointless.

If all else fails I would look at some sort of small DC recirculating pump that is compatible with potable water systems.

@innversion
yea like i said its kind of a wait and see thing, im in no rush at this point to start buying parts for my rig two years down the road. thank you for your advice though it was helpful.

I have recently come to the conclusion though that I will not be able to do anything about the condensation. when ever a lot of water is used in my home the water in my lines will drop to roughly 7 degree's... well below the rooms ambient temp of 21-23. Building a sealed case or using mineral oil to protect against condensation I feel is to extreme a solution to the problem... so for the moment I feel I am better off building a massive reservoir into the wall just like an old toilet tank and use that. I generally only game for 2-3 hours at a time 10-20 Litres should be more then enough for the user friendly(AMD CCC) over clocking that I do. I may still try this theory out, who knows maybe if enough heat is transferred through the heat exchange I would be able to heat the water close to room temp, its hard to say. This idea would work great for ridiculous overclocking, stress tests and computers being run hard often.. however until I can think of a worthwhile solution to the condensation issue, I think this idea is going on the back burner for now.


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## u3b3rg33k

Quote:


> Originally Posted by *Throwastone1990*
> 
> @u3b3rg33k
> your going to have to draw a diagram or somthing I am having a hard time imagining what your saying, sounds to me like you want to run your cold potable line right through your pc water cooling,you cant do that for multiple reasons biggest one being contamination from lead and other materials that are in the PC cooling supply the second being I don't think the fittings can handle the 60PSI your house is running at.


Are you not familiar with remote boiler water heaters? they have a potable side (the tank), and a non-potable side (the inside of the HX). you put one of those in front of your regular water heater, and the PC loop is isolated by the HX in the tank. instead of two pipes (in/out) you have 4. in/out for the HX, in/out for potable.

PC loop <-> HX I linked to (isolation) <-> HX/storage heater combo(isolation) <-> feed to hot water heater.

like this:

replace the boiler with your PC.


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## Throwastone1990

Ohh im with ya now, ya I have never seen one in a configuration like that, most tanks that I install with a built in heat exchanger heat the water themselves and the heat exchanger is for the domestic side(heating side) those tanks are pricey though so most people just opt for a standard hot water tank with a heat exchanger mounted on the wall. That's a good idea though, what do those tanks go for any idea?


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## rcoolb2002

A DC circ pump would be fine, but you still have to bump the pressure back up to get it back into the household system. Thats what I was referring to with a lift pump/ surge tank.


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## bombastinator

Having a cpu cooled to below dew point causes condensation issues no matter what the cooling source is. You'll have to insulate it like it's a peltier system. Also 10c° is not a limit for what you describe. Move to automotive radiator fluid, and you can get down to -20c°


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## bombastinator

Btw in your professional opinion is the thermal gravity thing workable? I have a landlord's knowledge of thermal gravity heat, but not a professional's


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## bichael

More engineering over analysis, haha&#8230;.

The heat recovery aspect to the hot water is nice if it could be made to work. Annual domestic hot water could be in the order of 2000kWh/yr (obviously varies with family size etc). If you were to allow for a PC running 12 hours a day at an average of say 150W that would be 1.8kWh/day or 657kWh/yr. So depending on PC usage it could be a meaningful contribution, and the bonus is it would also be reducing summer overheating/cooling in the room by the same amount.

The big if is whether you can arrange it to usefully capture that heat though. For heating the water you want high temps whereas for the pc cooling you want low temps&#8230;

As you say working out what temperatures would end up at is tricky, and avoiding condensation potentially the biggest problem.

If considering it as a fixed volume over a day then for 50 litres of water 1.8kWh would raise the temp by around 30oC. Heat loss from pipes and convection to the cold water main would leave it somewhere below that though so I suspect it would be okay. When the PC is off overnight then the temperature would drift back down towards room/cold water temp. If the loop is relatively big it would take quite a long time to get close to the water temp I think (remember water isn't being mechanically pushed around the loop at any point it's only via convection) but of course if the PC was off for a few days that would seem likely, even worse if the house was empty and unheated at the same time.

Condensation may not be that bad depending on the climate though? It certainly won't be anywhere near as bad as sub-zero water cooling setups anyway. Low cold water temperature will be at the time of year when the outside air is also cold and dry - eg. internal dew point in winter may well be less than 7oC anyway. I had uninsulated cold water pipes in the UK and never noticed any condensation issues.

My only ideas were a) if you had a variable pump on the pc side you could reduce pump speed when cold water temps are low which may help b) you could add valves in the loop on the domestic side to throttle the flow generated by convection, again I imagine it would just need to be a manual seasonal thing though and would be pretty difficult to know how to set it unless you have temp sensors everywhere.


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## u3b3rg33k

Quote:


> Originally Posted by *Throwastone1990*
> 
> Ohh im with ya now, ya I have never seen one in a configuration like that, most tanks that I install with a built in heat exchanger heat the water themselves and the heat exchanger is for the domestic side(heating side) those tanks are pricey though so most people just opt for a standard hot water tank with a heat exchanger mounted on the wall. That's a good idea though, what do those tanks go for any idea?


Ours is like that - 1 boiler, multiple zone valves. boilers are big and noisy, who wants more than one?

no clue on cost.


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## Throwastone1990

@RCool dude.. no disrespect but all the issues you have mentioned are irrelevant in this system. I said it in my initial post.I have explained it again to other users, I even explained it in my initial response to you the house water and pressure inst making contact with the purified water in my PC cooling loops. I am using what is called a heat exchanger which uses conduction to transfer heat from one source to another. They work by running two separate copper loops side by side this causes the heat to move from one loop to the other. notice how there is two loops? one loop has my house pressure on it the other loop is the PC cooling loop which only has the pressure created by the pipe size, reservoir volume and the recirculating pump.

@bombastinator yea but in the winter we generally keep our house at 21-22 summer usually 23-24 C so for those times when I am running the PC and someone is showering or anything that uses enough water it may cause my potable cooling loop to go from room temperature to 7C(out of my ass number honestly) which could cause condensation depending how much of the cold is transferred to the PC loop. I would just hate to be getting my ass kicked in BF4 chirpin some kids sitting in my underwear and all of the sudden my computer shorts and catches fire..

can convection circulate water? yes but what kind of system are you talking about? the point of a recirculating pump in a plumbing system is to save water usage and give you hot water quicker. convection is slow. say you have a 8 floor apartment building through convection the water coming from the tank would rise up the pipe but by the time it reached the 4th floor it became room temperature.(especially when it comes to copper pipe) now you have the poor bastard on the 8th floor who now has to run 30L of water out of the pipe riser just to take a hot shower.

While I have never installed or seen this there is gravity assisted system, there is a bigger better name for it.... basically you just loop your hot trunk line with a small amount of fall on the return pipe all the way back to the hot water tank. on both supply and return pipes you cant 90 down then back up causing a heat trap.

@u3b3rg33k

I mostly do new construction. radiators and such are extremely rare. Most of the time now people install a forced air furnace with a hot water tank and heat exchanger for there radiant floor heating. My house we have a wood/oil combination boiler, we heat our forced air through a air handler(basically reverse rad used to heat air) and have multiple zones for our radiant floor. for the fall months when we aren't using the boiler we use a propane hot water tank that is also hooked up to our air handler.

bichael
Don't worry I am definitely interested, just takes me a minute to follow your math









from what I am understanding you are assuming that the 5.48 kWh/day heating element would put out the same BTU's as a 5,48kWh/day PC would? for all I know they do but im betting they don't. not saying theirs no worth in sending the return line back to the tank, just saying theirs a lot of variables we are choosing to ignore, Ie fixed water in a hot water tank, amount of temperature loss across the system. This is one of those things we really need a test rig set up. I would really like to know though how you calculated the temperature increase over the volume of water. I could probably find the formulas in my old school books... but I don't want to









I am not sure how bad condensation would be. I just don't think it's worth the risk when it comes to a 2000+$ rig. You are right though there are solutions, I don't know if you recall but in my diagram there is a pink 1/2 pipe between the supply and return right above the heat exchanger. I figured if I put a back flow preventer on the cold supply the water would flow through the heat exchanger warm the water and then some would travel down the 1/2 line to the cold supply warming it. I would use a globe valve to throttle this. The problem is im not sure if the PC will put out enough heat to truly warm the supply line when in use/used else wear. I could also bush down the return line to the HWT to 1/2 or 3/8's or use anothre globe valve to slow the flow, lower the volume to try and retain more heat? It's not like the water will be cold all the time or even the majority of the time, it's just those high use occasions that scare me. The problem as you mentioned with use valves to throttle everything is now I need tons of gauges, need to watch the guages and manually adjust all the valves if/when the water temperature changes drastically. basically turns my brilliant







high performance self maintained system and makes it incredibly manual. now find me a mixing valve that electronically monitors cooler temps and adjusts it'sself accordingly preferably with a good length 4 pin PSU plug

I did just think though heat exhangers are not 100% effiecient so even if the water is 7 on the potable side its probably still going to be 5 degrees highers on the domestic side. the heat exchanger in my HWT to air handler set up is 3-6 C cooler i think?


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## u3b3rg33k

you asked about tanks and stuff:
http://www.bradfordwhite.com/residential-powerstor-series-ss-indirect-water-heaters
Stainless HX.

RTV-40-L 40 Gallon Capacity google has it for $875. I'm sure a better price can be found on a similar item by NOT using google shopping...


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## rcoolb2002

Quote:


> Originally Posted by *Throwastone1990*
> 
> @RCool dude.. no disrespect but all the issues you have mentioned are irrelevant in this system. I said it in my initial post.I have explained it again to other users, I even explained it in my initial response to you the house water and pressure inst making contact with the purified water in my PC cooling loops. I am using what is called a heat exchanger which uses conduction to transfer heat from one source to another. They work by running two separate copper loops side by side this causes the heat to move from one loop to the other. notice how there is two loops? one loop has my house pressure on it the other loop is the PC cooling loop which only has the pressure created by the pipe size, reservoir volume and the recirculating pump.


Wow I totally didn't catch that you were using a heat exchanger. Guess I was zoned in when someone else commented on raw water being bad for the system. I was thinking you meant to use the house water pressure. A water-water heat exchanger setup would be extremely simple.


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## bichael

Yeah the heat output at the pc is there but whether that all makes its way to usefully heating the water and reducing the work of the how water boiler is another matter.

In terms of the calc then for a fixed volume and heat energy then:
Temp rise (oC) = heat energy (kWh) / (volume (litres) * 4.18 (heat cap) / 3600)
Which is similar but different to that for a given heat power and flow:
Temp rise (oC) = heat power (kW) / volume flow (litres/sec) * 4.18

Yep can definitely understand not wanting to take the risk regarding condensation! I checked my room temp/RH last night and we were about 21oC/45% on a rainy winter day (which would be about my worst case). That's a dew point of about 9oC so probably close enough there is a risk though I'm still not sure there would actually be condensation. Maybe you could just rig an uninsulated cold water pipe up in the space and check to see if you get any condensation?

For the arrangement you showed I think one issue is that as you suggested you need heat from the PC so you have heat to mix back into the supply. At startup and when in idle there will be little heat and so no real temperature rise. Also I think to get flow down that branch you may need the valve in the return line not the branch, but again the issue is how you would ever set it.

For a water-water HX I would normally design for an approach of around 2oC. However in this case I guess you will likely have an oversized HX if it's at the scale of a domestic water system rather than a PC system? Given a big HX and low flowrates it may be that temperatures on either side can therefore get pretty close.

I wonder if you could use a motorised 2port on/off valve, the idea being to just simply close off the potable loop when temperatures are below a certain level. Something like below. I would have thought you only need one although really not sure and two may be better as I guess there would still be some heat loss via the return even with the supply closed.
http://www.screwfix.com/p/drayton-za5-679-2-2-port-motorised-valve/32455

To keep controls (relatively!) simple and more or less off the shelf I was wondering if you could interface the valve with a cylinder stat and have a very small tank in the loop (not sure what options are for a small reasonably priced tank with the right connections though). It controls down to 20oC which would be about what you want though you would need to reverse the output so it closes at low temps rather than opens. The tank may also help as a buffer and driver of the convective flow.
http://www.screwfix.com/p/siemens-ram1-cylinder-stat/76904

Quick sketch as below. One other concern I had when drawing this is how the convection current would get started initially, hence the 'angled' HX. Having an oversized HX is probably going to help with that.


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## bichael

Or even better a pipe stat, not sure why I didn't think of that before.
http://www.draytoncontrols.co.uk/PTS1Strap-onpipethermostat.aspx

Or a tap stat though not sure what the control would be like with that but it has the advantage of being non-electric.
http://www.draytoncontrols.co.uk/TapstatCylinderControls.aspx


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## bombastinator

google shopping = the high price network. It's consistantly at least 20% over other online retailers. Worst "service" ever.


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## bombastinator

Quote:


> Originally Posted by *bichael*
> 
> Yeah the heat output at the pc is there but whether that all makes its way to usefully heating the water and reducing the work of the how water boiler is another matter.
> 
> In terms of the calc then for a fixed volume and heat energy then:
> Temp rise (oC) = heat energy (kWh) / (volume (litres) * 4.18 (heat cap) / 3600)
> Which is similar but different to that for a given heat power and flow:
> Temp rise (oC) = heat power (kW) / volume flow (litres/sec) * 4.18
> 
> Yep can definitely understand not wanting to take the risk regarding condensation! I checked my room temp/RH last night and we were about 21oC/45% on a rainy winter day (which would be about my worst case). That's a dew point of about 9oC so probably close enough there is a risk though I'm still not sure there would actually be condensation. Maybe you could just rig an uninsulated cold water pipe up in the space and check to see if you get any condensation?
> 
> For the arrangement you showed I think one issue is that as you suggested you need heat from the PC so you have heat to mix back into the supply. At startup and when in idle there will be little heat and so no real temperature rise. Also I think to get flow down that branch you may need the valve in the return line not the branch, but again the issue is how you would ever set it.
> 
> For a water-water HX I would normally design for an approach of around 2oC. However in this case I guess you will likely have an oversized HX if it's at the scale of a domestic water system rather than a PC system? Given a big HX and low flowrates it may be that temperatures on either side can therefore get pretty close.
> 
> I wonder if you could use a motorised 2port on/off valve, the idea being to just simply close off the potable loop when temperatures are below a certain level. Something like below. I would have thought you only need one although really not sure and two may be better as I guess there would still be some heat loss via the return even with the supply closed.
> http://www.screwfix.com/p/drayton-za5-679-2-2-port-motorised-valve/32455
> 
> To keep controls (relatively!) simple and more or less off the shelf I was wondering if you could interface the valve with a cylinder stat and have a very small tank in the loop (not sure what options are for a small reasonably priced tank with the right connections though). It controls down to 20oC which would be about what you want though you would need to reverse the output so it closes at low temps rather than opens. The tank may also help as a buffer and driver of the convective flow.
> http://www.screwfix.com/p/siemens-ram1-cylinder-stat/76904
> 
> Quick sketch as below. One other concern I had when drawing this is how the convection current would get started initially, hence the 'angled' HX. Having an oversized HX is probably going to help with that.


I see a possible issue with that. you've got to have the water running for it to cool. if there's no tap open there's no water movement.


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## u3b3rg33k

Quote:


> Originally Posted by *bombastinator*
> 
> I see a possible issue with that. you've got to have the water running for it to cool. if there's no tap open there's no water movement.


That's what the small tank is for?
Quote:


> Originally Posted by *bombastinator*
> 
> google shopping = the high price network. It's consistantly at least 20% over other online retailers. Worst "service" ever.


I only used that to show that the product exists/demo what I'm talking about. if I were actually going to buy one I'd do more research.


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## bichael

The idea is that buoyancy / convection moves the water around on the non-pc side of the HX, facilitated by nice big domestic sized pipes etc. so although driving forces are small pressure loss is also small. Opening a tap will flush the cold water main which is acting as the final heat sink but won't move any water (at least not in any significant quantity) through the loop and HX as most of the water would just go straight down the main. When the valve is closed water would circulate just between the HX and tank until the temperature raised enough and the valve opened again.

In terms of the whole loop and water main heating up when there's no flow in the main then the assumption is that there is enough volume to limit temperature rise until the next cold water 'flush' and some heat would just be lost via conduction through pipes etc as well.

I did think a way of making it simpler could be to make the tank I added open and non mains pressure. This would mean any used water would have to go to drain so unfortunately loses any heat recovery and there would be some water consumption, though I think that would be relatively small (could use for watering the plants?!). The advantage would be that options and cost for a tank at non mains pressure become a lot easier and more in reach of a diy type solution (I think someone mentioned toilet cistern before?!). This could work as per my original sketch with a HX below the tank but I also wondered if it could be further simplified by circulating the PC side pipes directly though the tank with some sort of coil.


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## u3b3rg33k

Swap your tank for the one I linked to. problem solved! you can run 60/40 PSI working pressure on the inside of the tank, and hook your PC loop straight to the HX. no wasted water, no extra pumps, no wishful thinking regarding thermal gradients and flow rates.


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## Throwastone1990

@ u3b3rg33k
You don't offer a solution to condensation from the occasional cold water that the tank may receive. unless you shut off both the supply and return untill you feel the water has gotten too warm. You could also use bichael's thermal stat idea.. provided we can make it close when the supply temps drop below 20oC

@ bichael
That idea could work....as you said the challenge is making that valve close when it receives cooler water instead of warmer. assuming it uses a mercury switch it would be impossible to reverse, also very dangerous to install on a potable water system, that is a domestic heating component. Rigging that valve to a electric tank may be possible.. im trying to remember how the aqua stats are usually arranged. if you reverse the wiring on the aqua stat in theory it would shut off when the low temperatures hit the tank(if you wired the valve to the low limit... the issue is those aqua stats are designed for hot water so the low end maybe still be higher then what we require and with mechanical aqua stats there really isnt and adjustment that can be made... no idea about any designs for cooling. provided we could find a mechanical valve that suits are needs.. I would probably add a backflow preventer just to help force convection to circulate the way you designed... I still dont understand why the angled heat exchanger makes any difference, is it so the flow circulates the way you want? Though if you want to lower the pressure from the cold supply witha PRV you will then have to do the same for the return, making it impossible to circulate the water. Like you said there will be no more heat recovery so you wouldnt need the return line to the cold water supply.

Just to make things cheaper and easier you may as well just use a back flow preventer/ball valve and keep the tank at system pressure and use a globe valve on the potable return so you can recycle water as needed. This also allows you to temper the water manually so the condensation concern is gone. This is all assuming we just decided to go with volume and usage as a cooling system ie 30L will give me 4 hours of high end gaming, encoding etc.

I do like adding the tank though, if the mechanical valve did shut off it ould give some room for water to heat. I could pick up a tank relatively cheap. However using a tank with a build in heat exchanger is usually more expensive then getting a basic tank with a seperate heat exchanger.. atleast from what I have seen.


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## u3b3rg33k

Quote:


> Originally Posted by *Throwastone1990*
> 
> @ u3b3rg33k
> You don't offer a solution to condensation from the occasional cold water that the tank may receive. unless you shut off both the supply and return untill you feel the water has gotten too warm. You could also use bichael's thermal stat idea.. provided we can make it close when the supply temps drop below 20oC


run your pump on a speed controller, and have it pump slower when the water is colder?
put in a solenoid valve and recirculate a percentage of the flow to keep the loop above the dewpoint?
insulate the pipes?
run a de-humidifier? I don't have water dripping off of my below ambient pipes most of the year...

there's plenty of options, I'm not here to design it for you, I'm just throwing ideas at the wall.

you can't close the valve on a closed HX loop, it would overheat quickly (a few minutes perhaps). That'd be like running your boiler with no load - BAD! Remember my idea does not have some random tank with water draining out, I just threw a big tank of cold water in line with your water heater's inlet so you can dump all of your PC's waste heat into something you're paying money to dump waste heat into on purpose


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## bichael

Yeah the angled heat exchanger was just so that on start up any hot buoyant water generated within the HX would find it's way out of the correct side of the HX. The actual installation might depend on the flow paths through the HX (which would be something to consider when selecting the HX as well) but the general idea is to make it easy to establish the convection current without trapping heat anywhere - a bit like trying to establish draft when getting a fire going with an open chimney.

Also I get the idea of the backflow preventer but you may need to double check what it's operation would be with very low differential pressures and flows? I'm not familiar with the mechanics of the different types so can't really comment, just I guess the usage may be a bit different to what they're designed for.

I certainly think u3b3rg33k's option of taking the pc loop to an indirect cylinder would be good for heat recovery, and I wonder if condensation could maybe be avoided by having the cold water bypass the 'pre-heat' cylinder when it starts getting cold (3port valve with tank stat). I just wonder though if it would mean;
a) having a big tank close to the pc (there may be smaller ones but those indirect tanks I'm aware of are typically around 100 litres or more - part of the thinking behind the open tank option was that it could be pretty small and more easily custom built into a wall, like an aquarium or something)
b) having a long pc loop with a lot of water in it (of which I have no idea what the limit and implications might be)

Certainly plenty of options and things to look into!


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## u3b3rg33k

BTW that HX I linked to earlier has a design pressure of 140PSI. it'd probably survive in a 60/40 system without issue (put a hammer arrestor on the line if you're worried), if you wanted to DIY with a cheap storage tank (bargain/used water heater not hooked to gas/electric + a recirc pump and some plumbing?).


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## Thick8

Didn't read through all of the posts in this thread so sorry if it's been mentioned. You live in Canada. Go geothermal. chiller box with a radiator first in the loop. No insulating of the board necessary. The issue with tap water is that it has a lot of "stuff' in it. Stuff is bad for the small channels that make up water blocks. You need a closed loop or ultra filtered water. Dig a hole and throw some copper pipe in it. Insulate it against freezing. Man, I wish I live in Canada... Except for the fact that it's 60f here in SC today. I had to wear a sweater! BRRRR cold...


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## ssateneth

I'm not 100% sure on the diagram, but I believe I see 3 problems with this.

1. High pressure. Most blocks are not designed to work with mains-like water pressures. Sure you can use high-pressure tolerant tubing but the blocks will bulge out and the plastics could crack.'
2. I don't see a pump in your diagram, which implies you are using the flow from the mains to maintain coolant flow. If you have nothing in your house using water, your coolant will stagnate inside your blocks, causing temperatures to skyrocket within seconds, easily boiling the water inside and, again, causing pressure/bulging problems and potentially causing your blocks or tubes to explode.
3. You are using city water, which has a lot of additives. This can cause a lot of buildup and corrosion within your blocks. You probably won't need to worry about microbes, but the chemical reactions and battery-like reactions (You don't know what other metals are used in your city water lines) will eat away at the metals in your loop.

I don't see this being a viable liquid cooling solution.

If the aim of this was to have a noiseless PC, do what I do. Use standard liquid cooling components, but instead of having the fans/pump/other noise-making parts in the PC, run long coolant tubes to another room, or outside, where you can't hear it. If you choose to run them outside, make sure to use a coolant that's tolerant of sub-zero temperatures. In dry environments (<20% humidity), I don't foresee condensation being a critical problem. My ambient is 21C and 17% relative humidity, with outside ambients at -8C. My components surface temperatures is 3C and not getting any condensation. Any significantly lower and they'd be freezing any posible condensation

(Yes, I live 'dangerously')
(Yes, I know, I don't have my SLI bridge attached)


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## HIGHPOINT

Quote:


> Originally Posted by *bichael*


Quote:


> Originally Posted by *Throwastone1990*
> 
> .


Perhaps I missed something... I haven't read the entire thread but where are you exchanging water back into? I certainly hope not back into the potable line. I could see a closed system to exchange heat and only use potable water to top off low levels. BUT keep any return water away from the drinking supply, if not you're seriously going to cause havoc to the entire home system and your health.

I can only imagine this:


However, why not setup some type of grey water system then filter and store that in a small/medium water tank. Use any overfill for plants and overgrowth in your yard, etc.. that way you're not messing with your home plumbing and dread it a couple years later. IMO.


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## Throwastone1990

@ssateneth and high point: I am using a heat exachanger to keep the pressure and the "contaminated water" out of the water blocks. This enables me to use dystilled water or glycol on the pic side of the setup.

Ssatenth I was hoping to use convection for the hot water from the heat exchanger to be dissipated and transferred into my hot water lines. The pc side of the heat exchanger would have it's standard pump and reservoir. Just instead of a rad it uses a heat exchanger to conduct the heat to my home
Plumbing and hot water tank.


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## Throwastone1990

This was a idea I had awhile ago which I still won't be implementing in awhile. With my current rig working good at 1080p (7950 crossfire i73820) at ultra settings I haven't been rushing to rebuild yet.. Plus bought a house and other things.
I still plan on doing similar some day, but I may just use a small separate tank instead, i don't tend to game more then a few hours at a time I figure 30l storage reservoir would give me plenty of game time.


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## Simmons572

Hello! Just read through this the other day and I am really intrigued with the idea. I understand that this project is on hold for a while, but I look forward to seeing what develops in the future. (I am not a plumber so unfortunately I do not have anything useful to contribute to the conversation)


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## u3b3rg33k

Just look up heat pump de superheater dhw systems. It's not a novel idea - but code everywhere will require a double wall HX.


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## Simmons572

So I did a bit of thinking on this, and maybe someone can provide some feedback.

In my opinion, the fatal flaw with this concept would be the capacity of the water heater. If I remember this correctly, once the water heater fills completely, water stops flowing to it, right? Which potentially, this could mean that when the heater fills, then the water in the heat exchanger would stop flowing.

There are a couple solutions that I could think of to alleviate this issue:

1- Have some means of overfill control, where once the heater reaches capacity, a pressure release valve of sorts would allow water to flow down the drain.
I personally don't like that solution, as in a city environment, that would mean increased water bills, and wasting water softener pellets.

2- Set up a second heat exchanger with an external radiator solution, that toggles on when a flowmeter detects that the water pressure of the plumbing decreases too much.

I hope this makes sense.


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## u3b3rg33k

If you're in the US (or Canada and probably most of western europe), code demands that you use a double wall HX to separate your potable and non-potable water systems.

you basically MUST have something like this for it to be worthwhile:

regular water heater is left alone, and a tank is placed in front of it. the water in the un-plugged tank is circulated through your double-wall hx (via a pump), and your PC loop with pump is the other side of that hx. it's not complicated to have a rad/fan on a thermostat on the inlet side of your CPU block.

all the waste heat from your PC then goes to heating your hot water, and when you run out of capacity it just dumps into the room like normal.

no flowmeters/pressure sensors or elevated water bills.


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## Schmuckley

It would work but evap cooling makes water 6-11c lower than out of tap.
You may to add water 2-3x a week and clean deposits and things.
I'm real happy with the evap cooling.
It sounds like a refrigerator.


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## Throwastone1990

@ubergeek

The idea at the time was to not have a pump on the potable side. mostly because I don't know if there are potable DC recirculating pumps I could wire to a PC fan controller. I haven't looked into it. I honestly have no idea if the voltage would be to high.
We were thinking that there would be a strong enough convection current to keep the pc cool.


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## u3b3rg33k

Quote:


> Originally Posted by *Throwastone1990*
> 
> @ubergeek
> 
> The idea at the time was to not have a pump on the potable side. mostly because I don't know if there are potable DC recirculating pumps I could wire to a PC fan controller. I haven't looked into it. I honestly have no idea if the voltage would be to high.
> We were thinking that there would be a strong enough convection current to keep the pc cool.


if you want a strong convection current you will need a large delta T (temperature). your computer probably won't like that. im not sure why you'd need to wire the pump to a fan controller - if the PC is on the pump needs to be running, no? a relay/contactor should work.

the other option would be to have a tank with a built-in double wall HX (like an indirect water heater tank) built for such a purpose. then you could use a regular PC pump - otherwise you'll probably spend more money running the pumps than the CPU itself.


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## Throwastone1990

The tank with a built in heat exchange would eliminate the need for a second pump. You would have one pump on your PC side but with your diagram and my diagrams we would need a second pump to circulate the water from the heat exchanger to the tank. How would you make the recirc pump run only when the computer is on? Only way I could think of is somehow wiring it to a pc fan controller.


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## u3b3rg33k

Quote:


> Originally Posted by *Throwastone1990*
> 
> The tank with a built in heat exchange would eliminate the need for a second pump. You would have one pump on your PC side but with your diagram and my diagrams we would need a second pump to circulate the water from the heat exchanger to the tank. How would you make the recirc pump run only when the computer is on? Only way I could think of is somehow wiring it to a pc fan controller.


a 12VDC powered relay could control a 120V circulator pump no problem. run it off the molex or something. or just use a 12VDC pump in the PC - anything running on 120V is probably going to pull 50-100W and throw the energy savings out the window.

The reason most real-world setups use a HX and an unpowered electric water heater is cost - there's not much cheaper rated for 100PSI in the world of storage tanks. you're looking at 4x the price for a tank with a built in HX most of the time.


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## bichael

Just found that Koolance make a plate heat exchanger!
Just throwing it out there as could be a good option for anyone looking into this sort of thing.
http://koolance.com/hxp-135-compact-plate-heat-exchanger


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## HIGHPOINT

Quote:


> Originally Posted by *u3b3rg33k*
> 
> If you're in the US (or Canada and probably most of western europe), code demands that you use a double wall HX to separate your potable and non-potable water systems.
> 
> you basically MUST have something like this for it to be worthwhile:


Exactly, and not knowing the law and municipality codes isn't an excuse. You also need a permit(s). City inspector and the municipality will ding your wallet, potentially jail.


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## u3b3rg33k

I'm not so worried about jail/permits lol. But not introducing coolant to your plumbing is always wise. Also it's worth figuring out how to undo it if/when you move.


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## Throwastone1990

X like hell im pulling a permit to run two water lines to a heat exchanger, just a excuse to give money to the municipality.... especially when I installed the plumbing in the house purchased by the building inspector.


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## HIGHPOINT

Quote:


> Originally Posted by *Throwastone1990*
> 
> X like hell im pulling a permit to run two water lines to a heat exchanger, just a excuse to give money to the municipality.... especially when I installed the plumbing in the house purchased by the building inspector.


Who provides the water and sewage, and maintains it year round? Your municipality. They're there to help you and make sure things are in working order. If it harms the cities water supply... you'll be paying for more than a ~$50 permit. Either you're not from the States, if you are then you're clearly a generational idiot and tin-foil lunatic. If I were you, I'd call the city building inspector about your plan.

If you live in rural area and have your own septic tank and pump your own water, then that's a different story.


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## Throwastone1990

my water is metered, I pay for my usage and disposal. With the way we are taxed in Canada I don't owe my municipality anything.

General idiot with a tin foil hat huh....Is your house over 20 years old? Do you have a vacuum breaker on your external taps? Are they functioning? Just one example
of possible cross contamination Wells are also susceptible to bacteria and toxins. being rural doesn't necessarily change anything.

My municipality requires PRV or double check valves on the main entering my building. I am a licensed plumber, when it comes to plumbing I'm not getting a permit.


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