skanderson
New member
yes about 3 months max where the house is closed up and the heat is not wanted, about 6 months where the heat helps keep the tank and the house comfortable, and a few months where there is no benefit or drawback.
Heating a large system.
- Thread starter kcrush4989
- Start date
kcrush4989
New member
Are there literally zone valves like on a boiler that can be used? I'm afraid of back feed when showering or anything like that? I get the concept and like it. Just want to make sure waters doesent circulate when not needed.
sfsuphysics
Active member
1- you can buy a pump that pushes water, get one designed for this not an off the shelf aquarium pump, they're not cheap but they are rated to handle the pressure that you'll have in your pipes.
2- you can get check valves to make sure water only goes one way
There might be some slow drift of heated water simply due to thermodynamics, but overall if you set up your system correctly you should be good to go. If you add a heat exchanger and have a closed loop on the heating side then no worried about water moving when you turn on a shower or anything, although not sure that it would anyways.
Will F
New member
Yes zone valves like on a boiler. The system is a closed loop system so there is no real concern that water is back fed while in the shower. The only real risk I can think of is if the "heat exchanger" (pex coil) was to fail or leak you would end up with a fresh water leak.
The system opperates like a std heat system. Like in the home. When your living area is calling for heat the zone valve/circulator turns on and curculates hot water to radiators. This heats up the space. The pex coil is doing the same but instead of heating the space via air it is heating the water via the coil.
Hope this helps.
Will
fishguy306
Member
You guys using the water heater loop, I'm attempting to set one up now, for the life of me I can't get it to stop leaking where it connects to the drain on the heater. It has garden hose threads, I found a piece that converts to NPT on the other side and can get rid of the leaks there, but no luck on the drain valve. I've tried with and without thread sealant. It has the gasket in it but it keeps popping out of placewwheni screw the fitting on.
sfsuphysics
Active member
Why are you connecting to your drain valve on your water heater?
If you're doing an open loop, you connect to the exiting hot water to go to your tank, then the return connects to the incoming cool water. With a pump of course.
If you're doing an open loop, you connect to the exiting hot water to go to your tank, then the return connects to the incoming cool water. With a pump of course.
fishguy306
Member
To be honest that is the only way I had seen it done. The three or four I've seen build threads for all went back in the drain valve. I guess it was so you don't get warm water in your cold water lines. But if that is what people are doing I'm going to put in a T into my copper lines tonight and be done with it. I can sweat a pipe no problem and was thinking of replacing a dripping valve anyway. Maybe I'll just cut it all out and redo it tonight. Would make life much simpler.
sfsuphysics
Active member
Forget examples of heating your tank, look for those who use boilers for radiant floor heating, it's the same principle but with less heating necessary for our tanks people often tie into the water heater.
If you tee into the hot pipe, with a pump you can force water through your loop of pex or whatever you use, then the other side of that tees right back into the cold input for your water heater, as soon as water leaves the water heater it needs to be replenished, where is that going to come from? It's going to come from the water you're displacing in the heating line as the pump will push it through. The water will not circulate through the rest of the cold water lines of the house for the simple fact that if faucets aren't open water can't go that way, now it is possible if the heater is running and you're taking a shower it can go the cold way but a lot of that depends upon how close your open faucet is plus remember 40PSI (or whatever your street pressure is) will fight it.
That is an example of an open loop system, if you're really worried about the exchange do a closed loop system which involves a heat exchanger, and water from the water heater never goes to the tank it simply exchanges heat via the exchanger and the water in the tank's coil is always the same, you could also use a fluid other than water if you really want. It's a bit more safe/sanitary but it is a bit more expensive and complicated to setup.
Only reason I can think people attached to the drain valve was to tie it to the system in case there was a pressure issue... but I can't really wrap my mind around why you would do that even.
If you tee into the hot pipe, with a pump you can force water through your loop of pex or whatever you use, then the other side of that tees right back into the cold input for your water heater, as soon as water leaves the water heater it needs to be replenished, where is that going to come from? It's going to come from the water you're displacing in the heating line as the pump will push it through. The water will not circulate through the rest of the cold water lines of the house for the simple fact that if faucets aren't open water can't go that way, now it is possible if the heater is running and you're taking a shower it can go the cold way but a lot of that depends upon how close your open faucet is plus remember 40PSI (or whatever your street pressure is) will fight it.
That is an example of an open loop system, if you're really worried about the exchange do a closed loop system which involves a heat exchanger, and water from the water heater never goes to the tank it simply exchanges heat via the exchanger and the water in the tank's coil is always the same, you could also use a fluid other than water if you really want. It's a bit more safe/sanitary but it is a bit more expensive and complicated to setup.
Only reason I can think people attached to the drain valve was to tie it to the system in case there was a pressure issue... but I can't really wrap my mind around why you would do that even.
fishguy306
Member
Thanks for the information! That does make a lot of sense to me actually. I think that is what I'll do. Might as well replace do it the right way and get the leaking valve out of the way all at once. It'll cost me a few bucks extra but it'll be done correctly and a lot less likely to leak.
I've also looked into the open vs closed loop thing. I know the open is a bit more risky, however I plan on setting it to run once a day for 30 seconds regardless of temp to cycle it. Being in my basement I dont think I'll need it but rather safe than sorry. Thanks again for the info!
I've also looked into the open vs closed loop thing. I know the open is a bit more risky, however I plan on setting it to run once a day for 30 seconds regardless of temp to cycle it. Being in my basement I dont think I'll need it but rather safe than sorry. Thanks again for the info!
fishguy306
Member
Sorry for the double post, but just a couple more questions on this. I got the return plumbed in last night, solved all my leaks and everything. I have not put a solenoid on it yet, after my discovery this morning I think it is necessary. I ran the system last night. Tank and sumps were at about 69* when I opened the valves and turned them on, I let it run for a good 30-40 mins, it only got up to about 71.5* in that time. Now my house is cold at the moment, roughly 66*, and the hot water heater probably wasn't full completely while I was working, but I expected it to heat a bit quicker. In any case I turned off the pump and went to bed.
This mornings shower was only luke warm, I figured out the water was still cycling through the pex slowly, tank temp rose about another degree overnight. So I guess my concerns are that one, I feel like the HWH should be able to keep up with that slow cycle and not cause a lack of hot water? And two, everything I've seen implies this sort of system heats the water very rapidly.
I will say, my HWH is over 10 years old at this point. Without this loop it heats the water well still, too hot to stand if you go full hot, but I'm wondering if it just doesn't have what it takes to heat the water enough.
This mornings shower was only luke warm, I figured out the water was still cycling through the pex slowly, tank temp rose about another degree overnight. So I guess my concerns are that one, I feel like the HWH should be able to keep up with that slow cycle and not cause a lack of hot water? And two, everything I've seen implies this sort of system heats the water very rapidly.
I will say, my HWH is over 10 years old at this point. Without this loop it heats the water well still, too hot to stand if you go full hot, but I'm wondering if it just doesn't have what it takes to heat the water enough.
fishguy306
Member
It is fully turned up already actually. I've ordered a solenoid, I'm going to put it in and set it so it wont run an hour or so before people start getting up in the mornings, give it some time to heat back up
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