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Expansion Tank

Val_LI Member Posts: 9
Plumber I'm thinking to hire says I don't need Expansion Tank for my DHW.

I'm planning to have Lochinvar Knight boiler with Lochinvar 80GAL indirect water heater. There is NO recirculation line for hot water.

Plumber states since there is no recirculation line, no expansion tank needed.

Is that true? Please help me understand.


  • SWEI
    SWEI Member Posts: 7,356
    Some codes

    require them for all installations.  From an engineering standpoint, anytime you have a check valve (or something that acts like one) between the incoming water supply and the water heater, you need one.  PRVs act like check valves.
  • R Mannino
    R Mannino Member Posts: 440
    North Shore or South Shore?

    The north shore has higher water pressure which has presented a problem sometimes. I recommend the DHW expansion tank and some manufacturers require it for the warranty to be in effect. Just my two cents.
  • Robert O'Brien
    Robert O'Brien Member Posts: 3,512
    To learn more about this professional, click here to visit their ad in Find A Contractor.
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