Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

ERGOMAX Domestic Relief Valve?

Does a Ergomax E23 indirect tank need a TnP relief valve on the domestic side of the tank? The one i worked on did not and only had a 30lb relief valve on the boiler side of the tank which is correct. My question is "god forbid " street pressure increases or the thermex tank ruptures, where does the extra domestic pressure go or release? Thank you


  • Gordan
    Gordan Member Posts: 891
    Should be in the installation manual

    I'm pretty sure that every water heater is required to have a T&P valve on the domestic side. I just recently installed a Turbomax (reverse indirect like the Ergomax) and the installation instructions stipulated that a field-supplied T&P valve with a max 150 PSI rating (I think) be installed on the DHW outlet.
  • Jean-David Beyer
    Jean-David Beyer Member Posts: 2,666
    Relief valve on indirect?

    I do not have an Ergomax, but I do have a W-M (tank within a tank) indirect. The installation manual insists on a T&P relief valve, and specify that it should relieve at 150F and be rated at 100,000 BTU/hr (for the size tank I have). They do not say at what temperature it should release. I assume it is slightly below the boiling point.

    I could argue that since the hot water from the boiler is below the boiling point, that the water in the domestic part of the tank would not exceed the boiling point either. But I bet that argument would get me nowhere with an inspector, so I would not even try. Besides, if something went wrong with the boiler and the water did exceed the boiling point, it would be nice to have a relief valve in there.
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,853
    Absolutely required by code...

    Pick a code. Any code. They ALL require a working T&P relief valve within 6"s of the outlet of the tank on the potable side, AND an appropriate relief valve on the boiler side of the tank.

    The Ergomax and Thermomax are essentially large heat exchangers, but it matters not. If it generates domestic hot water, it MUST have protection.


    There was an error rendering this rich post.

This discussion has been closed.