[PLUMBER_BILL]

All this is news to me. I never knew the Grundfos comfort system bypass had a thermal control valve. Even when I've spoken with tech support in the past they just said its a simple check valve. Are y'all sure its thermally controlled? Being the timer on the unit controls the pump why would it be thermally controlled?

The timer on the pump is to turn it on lets say 6:45 A.M. and then turn if off lets say 9:39 A.M. Pump can be turned on and off according to life style. Control valve shuts off when hot water detected at faucet.

 

[ZL700]

Its a wax filled thermostatic valve in the crossover manifold that closes at approximently 104 degrees Fahrenheit. The pump is a low head (5') that is just large enough for a standard hot water tank and is small enough and designed to deadhead when the valve is closed. The valve reopens as the ambient air at the fixture cools the body.

Thus the nickname "comfort system"

Its meant to circulate an acceptable warm temperature to a faucet for hand washing. So not to be confused with a true recirculation system that circulates stored or heated domestic temperatures.

 

[Best Darn Sewer]

Its a wax filled thermostatic valve in the crossover manifold that closes at approximently 104 degrees Fahrenheit. The pump is a low head (5') that is just large enough for a standard hot water tank and is small enough and designed to deadhead when the valve is closed. The valve reopens as the ambient air at the fixture cools the body.

Thus the nickname "comfort system"

Its meant to circulate an acceptable warm temperature to a faucet for hand washing. So not to be confused with a true recirculation system that circulates stored or heated domestic temperatures.

Thank you for the explanation. So even if the timer is calling for circulation or if its on the 24/7 setting will it still not pump? Will the bypass control that? Sorry for my ignorance but I didn't know this about the comfort system.

 

[ZL700]

Thank you for the explanation. So even if the timer is calling for circulation or if its on the 24/7 setting will it still not pump? Will the bypass control that? Sorry for my ignorance but I didn't know this about the comfort system.

Pump runs when it told to whether moving water or not. Manifold passes water back through cold side when temp is low enough at manifold. Once hot water hits it, it closes to avoid too much hot water in the cold line.

 

[Best Darn Sewer]

Pump runs when it told to whether moving water or not. Manifold passes water back through cold side when temp is low enough at manifold. Once hot water hits it, it closes to avoid too much hot water in the cold line.

Very good to know. Thank you very much. I never knew that.

 

[realmenow]

grundfos

if the shower valve is a pressure balance type won't this affect how the bridge valve works??

 

[realmenow]

if the shower valve is a pressure balance type won't this affect how the bridge valve works??

 

[Plumbus]

I've had a Comfort System installed in my house for about 16 months. From day to day use, I can state that hot water does migrate into the cold side, sometimes it takes more than 10 seconds to dissipate, and this condition is apparent in faucets substantially remote from where the cross over valve is installed. After 30 years of interminable waiting for hot in the master bath and kitchen, it seemed the public spirited thing to do in drought suffering California. Had I better access I would prefer to install a properly insulated return line and use a recirculating pump with a timer and aqua stat.

 

[Plumbus]

Looks like water flow "should" come to a complete halt eventually in a new unit without debris. But in the first paragraph of the document it also states:
NOTE: Please understand this is not an anti-scald device. You may have some warm water in your cold water line under the sink where the valve is installed. Once the cold water line is opened, the warm water will dissipate in a very short time.

Here's an update on my situation. I changed out the cross over in March (while replacing the faucet it was attached to) and I've noticed it takes as long or longer for it to purge now.

 

[RichardBull]

I’m installing one of these on Thursday. I think it’s made by Watts.