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Paul SPaul S Member Posts: 1,229
Hey everyone....did heat loss calculation on a home...customer has regular gas water heater wants to switch to a indirect...if the heater is on hot water priority do I have to figure in the btuh loss of the water heater inn the boiler size. . Thanks Paul s
ASM Mechanical Company
Located in Staten Island NY
Servicing all 5 boroughs of NYC.
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  • kcoppkcopp Member Posts: 2,774

    The only exception I can see is if the DHW load is higher that the heating load.... and that is a rare happening.
  • GordanGordan Member Posts: 891

    The two will never be running at the same time.

    Typically you size the boiler to the space heating load, and then size the indirect to provide the required capacity with the boiler you have. If the heat loss is really low and hot water requirements really high, perhaps a separate appliance is in order (but this seems unlikely if they have a gas heater now.)
  • heatpro02920heatpro02920 Member Posts: 991
    edited March 2013
    I concur

    I don't upsize for DHW, unless the boiler is not large enough to supply enough btus for the indirect itself... I will on the other hand upsize the indirect to make up for boiler conditions... But priority is a must...
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