Water heater expansion tank.

James Day_2

What is the proper way to charge a expansion tank on a indirect water heater.



Thanks James

Mark Eatherton

Follow the manufacturers instructions...

and if my memory serves me correctly, it states that the diaphragm should be charged to the same pressure as the minimum operating pressure of the system, with ZERO water pressure on the tank. In other words, charge the diaphragm BEFORE you install it.



This way, any pressures generated by the expanding water will be absorbed by the tank and keep the pressure well below the relief valve setting.



ME

meplumber

I should probably read the instructions.

James, I have been charging them to 60 PSI for city water and 40 for well water. We have highly fluctuating water pressure here in the few areas with city water. We have found that we stay out of trouble at 60 PSI.



I think I will re-read the instructions on one.

Jean-David Beyer

Did any one ask...

... if the expansion tank is on the boiler side of the indirect, or on the domestic side?

James Day_2

expansion tank

Its on the domestic side

BobbyG

doesn't matter - domestic or heating

If you follow manufacturers instructions (like ME said above) then it wouldn't matter.

Set at minimum operating - then you have the correct amount of expansion room in the exp. tank.



If you did it like MEPlumber (for domestic) - that would work most of the time, but maybe not always - if the operating pressure were higher than 60# - less expansion room - relief valve go poppy or weepy, weepy, weepy every hot/cold cycle.



Big issue.