Quote:
Originally Posted by cypress
Do these units send the cool water in the hot water lines out through the cold water lines when replacing with hot. If that is the case would we be drinking water from the water heater?
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Quote:
Originally Posted by JerryP
Yes.
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Only for seconds then (if the HW is of concern) it's gone.
If you let the water run for 10 seconds there is no more tepid water in the cold line. I'm not worried about the minimal electricity used or 10 sec of tepid water from the faucet or saving a few cups of water. just the convenience. The water goes back to full cold in a matter of seconds after initial turn on.
This is a detailed explanation I found online:
The little bypass valve installed at the farthest sink has a thermostat valve inside that opens and closes depending on the temp. of the water. The pump located at the water heater forces the hot water into the cold line. Once the temp. is reached the bypass closes. So what will happen is when you first open the cold side you will get a small amount of warm water. The common area between the hot and cold lines is the water heater itself. so what is happening when the pump is on is the unit is pushing the water in a circle basically. Saves water. Only trouble is in a tankless type heater you loose your savings in having the heater since as long as the pump is pushing water the heater will be firing were as a tank type heater will only fire up once the content of the heater is tempered down to cause the thermostat to fire up. A tankless heater is not fired up using a thermostat but a Flow control valve/sensor. A tankless heater if you have a person that has a habit of running the water very low the heater generally will not fire up. You have to turn the water up higher and than close it down.