Water heater Pressure Relief Valve open up

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bdmeyer

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Maybe two or three times a week my PRV discharges water. I have the PVC pipe running into a 5 gallon bucket so it doesn't run all over the floor. It fills the bucket up about ever 4-5 weeks. Is this bad, or merely doing what it is supposed to do?

Thank-You
 

Geofd

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what temp is your water heater set at.....how old is the heater/relief valve
 

Diehard

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It is assumed that you are talking about the Temperature & Pressure Relief Valve.
So you say it periodically discharges as opposed to a constant drip?

There are a few reasons that could cause intermittent discharge.
1. Exceeds preset(Relief Valve) temperature occasionally.(Typically set at 210 degrees F)
2. Exceeds preset(Relief Valve) pressure occasionally.(Typically set at 150 psig)
3. Could be malfunctioning.

It may be doing what it's suppose to do but it's doing it because there's a problem.

Geofd has already touched upon items 1 & 3. So I will ask about the pressure.
Do you have an expansion tank on the water heater? Typically required if there is something on the water service line, feeding the water heater, that would prevent backflow, such as a pressure reducing valve, etc.
 
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bdmeyer

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Geofd and Diehard,
Water temp setting is unknown, I'll check when I get back home.
Unknown on Water heater age, I just bought the house a year ago, I'll have to look and see if there is a date on the water heater.
I haven't seen any type of an additional tank, so I am guessing it doesn't have an expansion tank.
Wow! The water temp is typically set to 210!!!? That's seems incredibly hot. I know when I run the hot water it isn't steaming, but maybe it loses a lot of it's temperature as it travels through the house?

Thank-You for your replies.
 

bdmeyer

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Ok, that's easy enough to do. I'll Check the temp, and if it discharges again, order the correct valve, turn off the water heater, cut house water off, discharge pressure from heater manually and replace the valve. Did I miss anything?

Thank-You for your help.
 

Diehard

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Just for your clarification, the 210 degrees and the 150 psig is what the safety relief valve is set to open at.
As already mentioned the safety relief valve is likely your problem and requires replacement.
As long as you are sure you don't have any type of check valve or pressure reducing valve anywhere on the cold water service feeding the water heater. Also, you don't have any water hammer in your system occasionally.
Just making sure we're touching all bases before replacing T&P relief valve.;)
 

bdmeyer

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Thank-You for the clarifications. I've never heard any water hammer, and having had to work through one at a previous house, I suspect that If I had one, I would likely know about it. This forum helped me resolve one many years ago. Very awesome folks here sharing their experience.
 

Mikey

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You might also pick up a hose-bib-mounted pressure gauge with a telltale on it to keep track of your peak water pressure. Ours used to be at 86psi from the utility, and would peak at well over 90psi on occasion. If the TP valve is weak, it might dribble on the peaks.
upload_2019-2-18_17-54-46.png
 

bdmeyer

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Nice! The one I have (For my RV) only shows green, yellow, red. Not too helpful in he house. My Water pressure was in the green. I'd rather have the PSI.
I measured my temperature at the sink near the Water Tank AND directly at the water tank. The water is 117.
I'll start looking for a new relief valve today (And Pipe Putty!)
 

bdmeyer

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Hi Folks,
Looking online at the relief valves, I see types that are different from each other. How can I know for certain that I am purchasing the correct type?
Thank-You.
 

bdmeyer

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Interesting in the red text. I thought I had read somewhere long ago to pull it once a month to make sure it was working. So, I've been pulling it once a month of decades. (Over my past 4 houses) I was wondering what that green and purple thing was that would chase me across the floor!
 

bdmeyer

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Notice the difference in length. This is what I mean by different types. I should have been specific. I 'think' that mine needs a longer one as it seems to go beyond the outer cover in to the inside of the tank. I hate to order the wrong one though.


 

Mikey

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The longer one just gives you more room for your wrench, I'd guess, but I welcome a more learned opinion.
 

CT18

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If you continue to open and close the T&P it could cause it to fail or get debris in it and leak. We were told many years ago to never break the vacuum of the tank with the T&P. We crack one of the dielectrics.
 

frodo

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Interesting in the red text. I thought I had read somewhere long ago to pull it once a month to make sure it was working. So, I've been pulling it once a month of decades. (Over my past 4 houses) I was wondering what that green and purple thing was that would chase me across the floor!

The reason you do not pull the handle is really very simple
the manufacture is the one who recommends you do that, NOT your plumber
WHY?? does the manufacture recommend you pop off the pop off?
simple,
inside that thing is a rubber diaphragm.. when you pop the thing. calcium deposits in your water
can, and DO, get stuck on the rubber diaphragm and cause it to dribble. he sells another one

You can not take that device apart and clean the rubber diaphragm when it leaks it is toast it must be replaced
and the only damn thing wrong with it, it has trash in the valve.
If you leave it alone, it will work when and if the temp on your heater asks it to work


tip.....if it does leak because it was popped off
rare back and knock the hell out of it with your plyers.
that works about half the time. lol
 

Diehard

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I have found that when a T&P valve is dripping, it's customary to allow some water to flow through in hopes to clear it. At that point, what do you have to lose?
 
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