Hot Water Coming Out of Cold Faucets

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Old 05-23-16, 07:06 PM
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Question Hot Water Coming Out of Cold Faucets

This just started happening a few months ago. No plumbing work has been done so I'm not sure why it's happening now. It's happening at multiple locations, not on one single sink.


Lower left is the cold water supply. Vertical left is going to the house. Vertical right is hot supply to house from tank.


When no water has been used for awhile (few hours), that left vertical pipe is quite warm, like water is going backwards through the tank.



Thoughts? Thanks.
 
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Old 05-23-16, 07:14 PM
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That is some mighty strange piping, was it that way when you moved into the house? Does the water heater not have any tappings/connections on the top? Is this a mobile home water heater?

If at all possible please post a few more pictures from different angles.
 
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Old 05-23-16, 07:22 PM
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Yes it's been that way since the tank was put in (2006). No connections on top. It's a SuperStor SSU-45. HTP site says nothing about it being for mobile homes.

The only other things not in the picture are the connections from the boiler.

Why is it strange?
 
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Old 05-23-16, 08:40 PM
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Ah, now that I know it is an indirect heater AND that you live in Massachusetts (missed that bit of info on the first go-around) it makes a bit more sense. I was wondering why the hot water outlet was teed from the safety valve connection and why the cold water supply was at the drain rather than the dip tube, which this heater obviously does not have. I also questioned why the cold water feed first went up and then down as well as that other valve on the cold water.

Massachusetts requires a vacuum breaker on water heater installations, that is the black knob/valve on the cold water feed. It has to be plumbed in that up-over-down arrangement in order to have the vacuum breaker operate properly.

I don't see a "tempering" valve in your pictures, you may not have one, but if you do then it is possible it is malfunctioning and allowing a backflow of hot water when a cold faucet is opened. Another possibility is that some single-handle faucets can allow a backflow from hot to cold under certain fault conditions.

That's all I have, maybe someone with more experience with the subject can offer more.
 
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Old 05-24-16, 07:14 AM
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I'll isolate my single-handle faucets one at a time to see if that's it.
 
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Old 05-25-16, 10:21 AM
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Well, none of my faucet's cold supplies felt warm. And there is no mixing valve so I'm sure what else to look at...
 
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Old 05-25-16, 05:04 PM
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Check the washing machine water valve when faucets are running.
 
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Old 05-26-16, 04:36 PM
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The washing machine valve? How would water cross thru that from hot / cold? Aren't the two completely separated?
 
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Old 06-01-16, 06:21 AM
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I found the problem. In the bathroom where my worst-offending faucet is, there’s a shower that hasn’t been used in 4 or 5 months (it’s not broken we just prefer the other one). Once every other week or so I turn it on for a few minutes just so nothing gets corroded or seized from disuse, but apparently this was not enough. Despite not being used for days, the valve is warm to the touch. It’s a Kohler valve, and I actually replaced it 2 years ago because the shower head was dripping while the valve was off. I know there is another device in there called a pressure-balancing unit, which I did not replace. Anyone have any ideas which item I should replace to solve this?
 
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Old 06-01-16, 08:23 AM
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I am not familiar with Kohler valves. Hopefully Mike (Lawrosa), our resident plumber, will see this thread and have some advice.
 
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Old 06-01-16, 01:37 PM
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The balance spool is common with kohler.. You should replace it..

Kohler may send you one for free..


JAG PLUMBING PRODUCTS Cartridge Spool for Pressure Balancing-18-588 - The Home Depot


But that is an odd set up. Almost like there is a recirc line on there.. Im not understanding that piping. Where do the boiler lines come into the heater?

Many times a failed check valve on the recirc line caused what your experiencing.. Or a faulty thermostatic shower valve..

Take a pic of the shower valve....
 
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Old 06-01-16, 01:41 PM
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The boiler lines are on the right side.

The 3/4" line going behind the tank goes around the wall to the sprinkler system, it's not part of the tank at all.
 
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Old 06-02-16, 01:12 PM
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Problem solved, it was that pressure unit in the shower. How it causes water to circulate thru the house I'll never know.

Thanks guys.
 
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Old 06-02-16, 03:01 PM
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Thank you for letting us know the outcome.
 
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