I have a ~90,000 BTU Arctic Air heat pump installed in newly replastered pool last summer. It services a 600gal spa and 22k gal pool, both indoor. I don't have any previous operating behavior yet (new house). This unit heats the spa at about 8F/hour which works out to about 40k BTU (just considering the heat going into the spa water). I don't know if that means half the heat is being lost heating piping and spa walls, etc or what. Assorted online rule of thumbs suggested this HP is undersized for this pool. I'm thinking it is slow for heating but will be very efficient maintaining temp once reached.
Another hypothesis is that the new plaster resulted in scale on the copper piping (?) inside the HP. I see a jump in pressure from 17 to 25 PSI when I open the valve to the HP so certainly something smaller diameter in there. Can someone else post spa-scale BTU losses on a HP or even gas heater?
Another hypothesis is that the new plaster resulted in scale on the copper piping (?) inside the HP. I see a jump in pressure from 17 to 25 PSI when I open the valve to the HP so certainly something smaller diameter in there. Can someone else post spa-scale BTU losses on a HP or even gas heater?