Turn off the cold water valve and turn on the hot water faucets to let the water out. Keep the drain valve open until all the water runs out and then close it. Step 5: Drain the Hot Water Tank. As you begin to understand how to turn off hot water heater supply, you'll discover a few facts.For your heater to work, you need hot water coming from the intake to the heater valve, and from there returning either to the water pump or the radiator. You have it coming from the heater to the water pump, and from the heater to the radiator- hence you have no flow of hot water through the heater. Inputs to the water pump are always returns.
Nov 01, 2020 · All tankless units have a minimum flow rate which must be achieved before the water heater will start heating water. Often, low-flow showerheads or fixtures cause the problem so the aerators inside should be removed. Other solutions may be to clean out the inlet water filter on the water heater or turn down the temperature on the unit. Reply