Water Heater Inconsistant Temperature Output

Hello,
Before I call another plumber to fix the issue, I just wanted to confirm my answer on the issue. I attached a photo diagram to better help get a answer.

On my current system, I am getting random temperature outputs throughout the day. I have two fifty gallon in series, (heater 1) is natural gas and active. Plumber set (heater2) as a passive storage tank, non active. I also have a circ pump that returns from the furthest part of the house. Also the temperature variation is not only measured at the furthest end of the house, but also at the closest faucet to the water heaters. Reason for two heaters, is that was the only way for me to get the house Energy Star and Efficient through the state.

I am thinking that the reason for the inconsistency is that (heater 2) is not powered. By having a plumber make (heater 2) powered this may solve the inconsistency of temperature. Is this the right line of thought? I have checked the system and can not see any other reason for temperature differences.

Thanks JR

is the recirc pump on a timer that may be off at some of the times you are checking?

not a plumber so not sure about this but i would have brought the return from the pump back into tank 1 instead of pulling the water from 2 into 1 to be heated when not being used.

Hello,

Thank you for the reply. Right now the recirc pump is always on.

JR

you may have infiltration of cold to the hot water side of the system. check piping at the washing machine or any appliance that uses hot/cold hookups, including those neat spickets that contractors like to put in garages and are left on all of the time to a garden hose.. and could be bypassing. Also your check valve could be sticking . just isolate the whole house at each appliance and see how you are going cold. trial and error.

Hello,

thank you. My apologies, I did check all the valves to make sure they are not filtering back into the main system.

I am just wondering if tank 2 needs to be heated at a lower heat.

JR

Not sure but if you have a tank that sits awhile the water warms up in that tank, once you start using water you eventually start feeding cold water into the first tank which starts to lower the temp in the second tank. Then everything sits awhile and gets warm and the cycle begins again. Just wondering did they strip the insulation off the first tank? If not its less effective because your holding the cold in instead of having the room warm it up. I would parallel the tanks and run both.

Quote:

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Originally Posted by Joehvac25

Not sure but if you have a tank that sits awhile the water warms up in that tank, once you start using water you eventually start feeding cold water into the first tank which starts to lower the temp in the second tank. Then everything sits awhile and gets warm and the cycle begins again. Just wondering did they strip the insulation off the first tank? If not its less effective because your holding the cold in instead of having the room warm it up. I would parallel the tanks and run both.

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With the constant recirc he has, the second tank should never get cold until he starts using alot of hot water.



OP, does the cold water feed into the first or second tank.

Form your diagram the first tank is the inlet and is storage. That is wrong. The supply water should come into the powered tank and leave heated to the storage tank. What you have is backwards.


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Quote:

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Originally Posted by beenthere

With the constant recirc he has, the second tank should never get cold until he starts using alot of hot water.



OP, does the cold water feed into the first or second tank.

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That's kind of what I was wondering if its after a long draw that he is asking or lets say the same shower gets hot then cold then hot again?

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Shouldn't the OP define what he means by "random temperature outputs"? Wouldn't any temperature between the water heater control's cut-in and cut-out be acceptable? Plus, allowances made for heat loss in the pipe?