Hot Water Heater Pop-off valve


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Old 01-26-13, 03:56 PM
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Hot Water Heater Pop-off valve

New to the site here....I need advice on what might be causing the pop-off valve on our electric waterheater to sometimes leak/run...seems to go off when we turn on the hot water. We do seem to have good to high water pressure here, so I'm thinking the surge in the pressure when the line is opened is what is causing the valve to open. Any insight to fix this would be appreciated, we just bought this home...it is about eight years old.
 
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Old 01-26-13, 04:54 PM
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Hi Pop,

I'm going to move your question to the "Water Heaters" forum after I answer.

Chances are pretty good that if your water isn't SCALDING HOT! that the valve is opening on PRESSURE. Those valves are COMBINATION temperature and pressure. (check the metal tag for ratings).

To verify the problem, pick up one of these and screw it on a hose bib someplace (make sure it don't FREEZE!) and leave it in place for a few days. The 'lazy hand' will record the high pressure it sees.

Compare the highest pressure to the rating of the valve. (probably 150 PSI)

You may need to have a potable water expansion tank installed if this turns out to be the problem.

The guys on the water heater forum will be able to assist you further.
 
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Old 01-26-13, 05:18 PM
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I would agree, check the incoming pressure of the municipal water (if that's what you have). Too high a pressure will cause the T&P valve to leak, provided temperatures are normal.

I Know NJTrooper missed a click, so here is the valve.

Name:  pressure gauge.jpg
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Old 01-26-13, 05:24 PM
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Also after the PSI is checked you may have a faulty PRV valve if your home has one.... Or if you have an exp tank that may be faulty....
 
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Old 01-26-13, 06:43 PM
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Thank you for the advice. I will pick up one of those pressure vales and compare to the tag rating. I feel like it is excessive pressure that is the culprit. I will check it out and get back with the results....again, thank you all for your help.
 
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Old 01-27-13, 04:32 AM
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Incidentally, your house water pressure should be in the 65 lb range, with a few variations. The higher limit on the valve is the protection value.
 
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Old 01-27-13, 07:32 AM
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Thanks Larry, yeah, I forgot the link I was gonna post...

Should be able to find those gauges at HD or Lowes... might be tricky this time of year as they are mainly used when servicing in-ground sprinkler systems... cost is around $10 or so...
 
 

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