New Hot Water Tank

[RAKocher]

Is that fairly recent? If not, the water heater that was plumbed backwards in my house for 20 years also had failed check valves.

Yes, we never enough hot water.

I bought and installed my last tank around 17 years ago and it did not have a check valve, but the one I just bought and installed last August does.

 

[kwired]

I bought and installed my last tank around 17 years ago and it did not have a check valve, but the one I just bought and installed last August does.

Can't say I ever recall seeing the "ball" type, but the flapper types aren't that great of a "check valve" They may impede flow but will not give you total back flow prevention.

As I mentioned in previous post the purpose of these is "heat trap" to lessen loss of heat when not using any hot water.

 

[RAKocher]

Can't say I ever recall seeing the "ball" type, but the flapper types aren't that great of a "check valve" They may impede flow but will not give you total back flow prevention.

As I mentioned in previous post the purpose of these is "heat trap" to lessen loss of heat when not using any hot water.

If you read where I describe my 2 tank setup, where my electric tank is an emergency backup to a heat exchanger tank fed from a propane boiler, and how I normally just keep all valves open and let whichever tank is heating the water to heat both tanks. Well, now if the new electric tank is the one heating the water the impedance to reverse flow caused by that heat trap is enough to prevent the water in the other tank from being heated.
It’s not horrible, but it is disappointing that before if the propane boiler conked out I just had to turn on a breaker, but now I have to close a valve to isolate the cold water in the main tank and also have a greatly reduced amount of hot water until the boiler is repaired.

 

[hbiss]

I try to keep up with current hydronic heating and the installation of condensing boilers but I'm no expert here. If it were me I would plumb the WHs in series, probably with the electric last. Might even leave the breaker on with the electric temp set the same as the gas. Theoretically it should only come on due to standby loss if nobody is using HW, or the gas can't keep up.

The plastic inside the nipple is a check valve to keep the water flowing in only one direction. There are usually two types flapper and ball style.

I've not seen that but then again it's been years since I installed a WH myself. Probably came about because of the energy saving requirements.

That method is not new. "Flow check" valves have always been used with hydronic systems that use individual circulators for the loops instead of zone valves. That's to keep the hot water from circulating via convection and heating the baseboard or radiators when the circulator isn't on. They actually have a knob type lever on top that when you turn it, it pulls up on the weighted check valve inside and allows free flow of the water. This goes back to the old days when boilers could operate without power. If you lost power, your circulators wouldn't work and by opening all the flow checks you could have heat. Opening the flow checks is also useful for filling and flushing the system.

-Hal

 

[RAKocher]

I try to keep up with current hydronic heating and the installation of condensing boilers but I'm no expert here. If it were me I would plumb the WHs in series, probably with the electric last. Might even leave the breaker on with the electric temp set the same as the gas. Theoretically it should only come on due to standby loss if nobody is using HW, or the gas can't keep up.

I opted for the tanks in parallel method based on recommendation by the HVAC contractor who I hired when building my home 30 years ago. We were installing one of the early high efficiency propane boilers that fed both a heating coil in an air-handler and a heat exchanger for hot water. The boiler was high maintenance primarily due to hot surface ignitor failures, so we installed an electric heating coil in the air-handler and a small backup electric hot water tank. He said if I hook the tanks up in parallel the small electric tank will heat the big tank too, which it did all these years until this new tank with its ‘heat trap’. I guess that’s the only advantage to a parallel hookup.over a series is that I could heat more water with only the electric backup tank.

 

[kwired]

If you read where I describe my 2 tank setup, where my electric tank is an emergency backup to a heat exchanger tank fed from a propane boiler, and how I normally just keep all valves open and let whichever tank is heating the water to heat both tanks. Well, now if the new electric tank is the one heating the water the impedance to reverse flow caused by that heat trap is enough to prevent the water in the other tank from being heated.
It’s not horrible, but it is disappointing that before if the propane boiler conked out I just had to turn on a breaker, but now I have to close a valve to isolate the cold water in the main tank and also have a greatly reduced amount of hot water until the boiler is repaired.

You probably want to remove the heat traps to use your two tank system the way you want to use it. If your other propane heated tank is newer it may also have heat traps installed.