Quote:
Originally Posted by rjm1cc
How does the circulating water get back to the tankless system when the faucet is closed? I have a regular system and when the pump is running I have a valve that opens between the hot water line and the cold water line and the cold water line is used to returns the hot water to my hot water heater. Sounds like your system is not returning the water.
AI suggest the following. Choose the right recirculation pump for your tankless water heater model.
Install a check valve and sensor valve in the recirculation line.
Install an aquastat on the tankless unit and connect it to the recirculation pump.
Set the temperature on the aquastat to the desired level.
Turn on the pump and test the system to ensure it’s working.
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It sounds like my system is using either the same, or a similar valve as the one you may have. The water recirculates internally using a diverter valve that is installed beneath a sink which ties the incoming hot water supply line to the cold water supply line and allows water in the hot water supply line to flow into the cold water supply line when the pump is active, thus acting the same as a dedicated return line. The diverter valve has a temperature controlled shut off or check valve inside it so that when the temperature of the water passing from the how water supply side of the valve exceeds a certain temperature, it will close.
I was able to test the valve by simply shutting off the incoming cold water supply at the diverter valve and then turning on the cold water at the faucet. Water flowed from the faucet indicating that water from the hot water side of the diverter valve was being supplied. As the water eventually heated, the water flow slowed and eventually stopped when it reached the prescribed temperature. For that reason I'm pretty sure that the valve is working properly.
From additional testing that I've done, it seems that (as suggested by another forum member) that the pump flow rate of the Watts system is not adequate enough to cause the hot water heater to turn on. As soon as I turn on the pump, the water heater throws a P1 code. If I leave the pump running with the P1 code still active and turn on the hot water inside the home, the P1 code instantly resets and the unit fires up.
At this point I believe that I will try to find another pump that has a higher flow rate. I looked for the GPM or flow rate specs online for the Watts pump but could not find any. There is another pump made by Grundfos that claims it can provide up to 9 GPM.
Thank you for your help and in pointing me in the right direction.