My question of How to plumb external heater would be the same for any external heater like solar heat to most any spa. However, my specific situation is ...
I have a Trinidad swim spa from Integrity Spas installed in a room with geothermal heat pump that has a waste heat recovery coil. I'd like to circulate pool water through that coil to heat the pool. The most convenient way to hook it up will be to draw water from the main drain and return it through the overflow drain. This would effectively disable the overflow drain, which is not a concern in my installation since the pool sits in a hole on a slab with a floor drain. Is this a common way of hooking up an external heater?
