Mixing valve for water heater with recirculating line.

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spete112

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I am trying to figuring out what size indirect water heater to purchase. I was doing some research that talked about one option of using a smaller size heater and increasing the water temp. If I was to use a mixing valve how would that work if I have a recirculating line installed.
 

Jadnashua

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The mixing valve would work exactly the same with recirculation. IF the tank has a recirculation port (most don't, but a few do), you'd use that for the return line, otherwise, you usually put a T into the drain line by moving the valve out to accommodate a T there. Having a dedicated return line is nice, but for retrofit, a lot of them are installed with the return line being through a cross-over into the cold line.
 

hj

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If installed that way, there is NO cold water flow into the line, and the pump will force hot water through the mixing valve, so the hot water line will fill with water at the heaters temperature, untill a faucet is opened to drain it out and the mixing valve starts working.
 

Jadnashua

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If installed that way, there is NO cold water flow into the line, and the pump will force hot water through the mixing valve, so the hot water line will fill with water at the heaters temperature, untill a faucet is opened to drain it out and the mixing valve starts working.
So, does that mean you put a T in the cold water inlet and run the return there?
 

spete112

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Thanks HJ that was exactly what I was wondering about. I just cant see turning on a faucet and getting 150-160 degree water out of the kitchen faucet. It sounds like my only option is to go with a bigger heater.
 

Terry

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If you have a tempering valve on the water heater, and a recirc pump, you must also have a AquaStat.
The aquat stat wires into the pump, and shuts the pump off when the return like reaches 108 degrees.
If you don't install this, the water temperature will eventually reach it's highest temperature.

So..........it's okay to recirc with a tempering valve, but "only" if you install an aquastat with it.

The timer is optional.

grunfos_recirc_chart.jpg
 
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