DOEL 20000 BTU Swimming Pool Heat Pump for In-ground/Above-Ground Pools, 5.56 kW Electric Pool Heater with Titanium Heat Exchanger, 110V 60Hz

I am using this with a 13′ x 48″ round above-ground pool (about 3500 gallons when filled to 42″) in the Pacific Northwest). On a 75-degree day, it raised the pool temperature by 10 degrees in 12 hours. You must purchase some adapters to make this work. If you have a pool pump/filter with 1.5-inch connections, search for “40mm to 1 1/2 Inch Hose Conversion Adapters.” If you have 1.25″ connections, you must buy a “Pool Hose Adapter 1 1/4 to 1 1/2 Replacement Hose Adapter w/Collar” to convert from the 1.5-inch adapter above. You will not use the included adapters unless you plan to use PVC pipe for your pool. The Maximum flow rate through the heater is 633/GPH; any higher than this, the unit will not work as there isn’t enough time for the heater to heat the water as it flows through. If your pool pump/filter has a higher GPH than that (most are over 1000/GPH for a pool you would likely heat with this), you will need to create a diverted loop that includes 2 Tees and some sort of flow restrictor so you can control the amount of water going through the heater while still allowing full flow through your filter. I used a plunger valve to reduce the flow into the unit, but it took some adjustment to get it right, as I have a 2500/GPH filter pump. Buying a pool diverter valve would also do the trick, but unless you plan to PVC plumb this, you must purchase many adapters to make it work. You may not need a flow reducer if your pump is 1000/GPH and you set up a heater loop, as at least some flow will go through the primary loop. There is a lot of trial and error. This unit comes screwed to a small pallet, and you need to make sure you do not tilt it much, as it can cause issues with the coolant.