Posted 1/14/2021 11:04 (#8750398 - in reply to #8749726) Subject: RE: Whole house tankless water heaters
East Central Missouri
How mine works, one water heater is hooked up (electric) and works as needed. Second tank is not hooked up to electric but hooked up in series with first tank through plumbing. As furnace or AC (actually heat pump) works it generates hot water which goes to first tank and draws from second tank. If the HVAC system works more than the hot water is used, the second tank slowly warms up as it is back feeded from first tank. As hot water is used first tank draws from second tank, heating prewarmed water as needed. Water enters the hot water circuit at second tank and and hot water goes to use from first tank.