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Summer Boiler Temperature for Indirect HWH


I have a Burnham ES2-4 boiler connected to a Brandford White 53 gallon Indirect HWH.  During the summer months, what boiler temperature would you run just to heat the Domestic Hot Water?




  • Project42day
    Project42day Member Posts: 3
    Add me to the folks also wondering how summer usage works with a gas fired boiler and an indirect hot water tank.
  • Derheatmeister
    Derheatmeister Member Posts: 1,472
    As far as i understand this is not a condensing boiler... This boiler may need to operate between 140F and 180F. Do not try to reduce the operating temp as it could create condensate in the Exhaust and the Heat exchanger which will cause corrosion to the Exhaust/Boiler(Void warranty) and a possible Carbon Monoxide leak.
    EBEBRATT-Ed Member Posts: 13,760

    If the controls are wired and working correctly the boiler will not maintain boiler water temperature in the summer. The control located on the indirect will fire the boiler and start the circulator or zone valve to allow the boiler to heat the indirect.

    The temp you maintain the indirect at (you will get varying answers on this) would be 120 minimum. Some locations are specifying a higher temperature and a mixing valve to be installed to prevent legionella.
  • hot_rod
    hot_rod Member Posts: 19,850
    if you lower the boiler to say 150-160 for indirect call, it will take longer to recover. And yes the boiler will be a tiny bit more efficient at lower operating temperature

    You probably have enough boiler btu to cover the indirect without condensing the boiler

    Unless you drain the tank down to 55F ut should recover  in 15 minutes or so. Assuming no dhw load

    Is it piped with 3/4 or 1”?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream