correct way to install water heater thermal return line

eric cowan

recently installed 1/2" pex thermal return line from master bath hot water line to 50 gal. elec. water heater.installed nipple and tee at boiler drain location.drilled 1/4" hole in swing check valve,mounted in vertical position with flow reversed to keep gate closed.customer complained of warm water at kitchen faucet,installed 1/2" spring loaded check on cold water supply to water heater.when you use hot water at masterbath it is back feeding through return line and water is not hot enough unless i close ball valve on return line to isolate thermal return from hot water supply.do i need an additional check on return? will this stop thermal flow?

eric cowan

thermal return line for tank type water heaters

recently installed 1/2" pex thermal return line from master bath hot water line to 50 gal. elec. water heater.installed nipple and tee at boiler drain location.drilled 1/4" hole in swing check valve,mounted in vertical position with flow reversed to keep gate closed.customer complained of warm water at kitchen faucet,installed 1/2" spring loaded check on cold water supply to water heater.when you use hot water at masterbath it is back feeding through return line and water is not hot enough unless i close ball valve on return line to isolate thermal return from hot water supply.do i need an additional check on return? will this stop thermal flow?

Unknown

Did it work

with gravity flow before ? Did you install a purge valve on the return line ? With the spring check there , you might have an airlock on the pex pipe .

If the line is full of water , I'd guess you'll need a bronze circ to pump the hot water back to the heater .

Eric_32

Return line piping

I have had problems with trying to use a gravity recirc. line. Sometimes the cold draws thru the recirc. line instead of the hot outlet of the tank, works fine until the bottom the tank gets cold then the customer complains of running out of hot water. I have only found a bronze pump and spring check to resolve this, with a bleeder just like a zone of heat. would love to know if there is a way gravity alone would work without any issues???

Unknown

Well ...........

gravity won't work with the spring check in there . I'm not sure what you mean by the cold drawing through the recirc line instead of the hot of the tank ? Where is the recirc pipe teed in ? In relation to the tank ? It might work , but you'll need a swing check and a purge station . Some checks need to be piped in horizontally to work though . Is that what you meant ? Cold water was backfeeding though the recirc pipe ?

But if you decide to go the pumped route , you really should not have a problem using a bronze circ in this application . Grundfos makes a nice one with a timer built in , and I believe it has a built in aquastat too . Pipe it into the bottom of the tank with a swing or spring check and purge valve and you'll be good to go . Good luck Erich .

Eric_32

recirc line

was piped to the cold drain at the bottom of the tank via a brass tee. Without any check installed, have had problems on a gravity recirc line with the cold water backfeeding thru the recirc line instead of out the hot outlet on top. I now install a bronze pump above that tee on tank drain pushing in to the tank, with a ball valve and another tee with a boiler drain to aid in bleeding. and finally above that the wonderful spring check to keep things in order. U have found that drilling a swing check can prevent any possible flow backwards thru the recirc line and avoid the pump? sorry for the long one.

Dan Sedens

Thermal flow through shower valve

It is possible that you may be getting slight flow through your tub and shower valve. I had a situation where we were getting hot water through cold faucets for a short period of time. Problem was resolved when we rebuilt old tub and shower valves. I don't know if it pertains in your situation, but it may help.

Dan