# Hot Water In Cold Water.



## cityplumbing (Jun 12, 2010)

Hopefully with this thread we can bounce some ideas around and I can help this customer out. Let me tell the history of the job. This house was built in 06 and was sitting till 2011 the house has one 80 gallon gas water heater with recirculating pump installed on the drain valve with a check. There's seven bathrooms, one outside single lever kitchen faucet, one inside single lever kitchen faucet, wash sink with a single lever Delta touch faucet, instant hot water dispenser every bathroom has body sprays and Aqua brass thermostatic valves all bathrooms also have wide spread faucets, copper water lines on the first floor are ran under ground to manifolds feeding each area. Water pressure is high at 90 PSI for cold water and hot.
The problem is 30 seconds of hot water in the cold water side of the inside single lever kitchen faucet which is the closest to the water heater also water is hot in the closest bathroom toilet tank and warm water in the cold water side of the lav faucet in same bathroom. After running the kitchen faucet until cold water is present it takes hours before hot water is present again. 
So far I have increased the size of the thermal expansion tank to the required size for the heater and added a check valve on the cold water intake of the heater. Added the manufacturer supplied check valves to the Delta touch faucet supply lines. Replaced all check stops for all Aqua brass thermostatic valves. Next place I’m looking at is the kitchen faucet itself and the instant hot dispenser also suggesting adding a pressure reducing valve on the main.
I'll be working after I post this so I might not be able to respond quickly to posts. Thanks in advance..


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## Gettinit (May 9, 2012)

What are they doing for re-circulation? If they are using the retrofit pumps like this Grundfos, there is not much you can do.


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## OldSchool (Jan 30, 2010)

Reduce the pressure for starters .,, then isolate the return by turning it off stopping the flow .., test fixtures again

I have had problems where the hot and cold would cross over in the faucet especially the tub and shower faucet with out it turned on...

Problem might also be in the mixing valves


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## cityplumbing (Jun 12, 2010)

The mixing valves in the kitchen faucet?


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## cityplumbing (Jun 12, 2010)

Gettinit said:


> What are they doing for re-circulation? If they are using the retrofit pumps like this Grundfos, there is not much you can do.


It's not a retrofit, it's a regular circulator the return is connected to the bottom of the water heater and it must be pulling from the furthest manifold.


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## plbgbiz (Aug 27, 2010)

Gettinit said:


> What are they doing for re-circulation? If they are using the retrofit pumps like this Grundfos, there is not much you can do.


...


cityplumbing said:


> ...the house has one 80 gallon gas water heater with recirculating pump installed on the drain valve with a check....


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## Gettinit (May 9, 2012)

plbgbiz said:


> ...


Missed that little tid bit.


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## cityplumbing (Jun 12, 2010)

Theirs just so many possibilities with this house its driving me crazy. The worst part is its a vacation house so I can only go there when he's visiting.


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## plbgbiz (Aug 27, 2010)

Maybe use a process of elimination.

Leave the stops off at certain faucets (one at a time) to see if it keeps the problem from recurring.


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## plbgbiz (Aug 27, 2010)

cityplumbing said:


> Hopefully with this thread we can bounce some ideas around and I can help this customer out. Let me tell the history of the job. This house was built in 06 and was sitting till 2011 ....


So this is the first occupant and the problem has been from day one, or is it a recent development?


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## cityplumbing (Jun 12, 2010)

I'm going to have to revisit the elimination process at next trip. He says its a new issue but I'm trying to keep an open mind.


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## UN1TED-WE-PLUMB (Oct 3, 2012)

I would bet one of the shower valves are mixing or another thing I have seen is where the front load washing machine will mix the water. Only seen that once it was surly strange but I see shower valves mixing all the time. You know it's a point where hot and cold run together, like scenarios described above. One other way to help eliminate would be to turn off every angle stop in the house then check everything.


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## gforsell (Sep 28, 2012)

What are the make/model of the tub/shower valves? I've seen Moen valves pass water from hot to cold and vice versa when not flowing water. If that's the case, make sure you buy the heavy duty replacement cartridges, not the cheap ones.


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## cityplumbing (Jun 12, 2010)

gforsell said:


> What are the make/model of the tub/shower valves? I've seen Moen valves pass water from hot to cold and vice versa when not flowing water. If that's the case, make sure you buy the heavy duty replacement cartridges, not the cheap ones.


Aqua brass thermostatic mixing valves with check valve stops in every bathroom. I replaced all the check stops in every bathroom.


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## plumberdad70 (Sep 29, 2012)

turn off the main and see what kind of pressure the recirc pump is putting out, i have seen some hitting as high as 140psi blowing fixtures apart!!!


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## cityplumbing (Jun 12, 2010)

plumberdad70 said:


> turn off the main and see what kind of pressure the recirc pump is putting out, i have seen some hitting as high as 140psi blowing fixtures apart!!!


The pressure in the water heater never passes street pressure with the expansion tank I installed.


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