# Leaking T&P



## Doubletap (May 5, 2010)

T&P is leaking (high pressure and no expansion tank)
I replace pressure regulator & T&P
I advise customer that expansion tank may be required. They say no just fix leaking T&P.
Next day T&P is leaking. Pressure is 80psi. No excessive heat. So I replace T&P with 175psi T&P. Still leaking. The customer wants to know why 20 year old water heat requires an expansion tank it never needed before. My question is "if I install an expansion tank am I going to fix it?"
Note: water heater is noisy


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## CaptainBob (Jan 3, 2011)

Is there a check valve or pressure reducer on the water supply to the water heater or to the water supply to the building?


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## Doubletap (May 5, 2010)

No check valve that I can see.


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## 130 PLUMBER (Oct 22, 2009)

Or is there a sprinkler system that was install???? sounds like you have a close system


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## Doubletap (May 5, 2010)

But there is a pressure regulator. But one of those has always been in the system.


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## The bear (Sep 27, 2012)

Is it possible water utility has replaced meter and added dual check. Also pressure reducer does it have built in bypass for water expansion.


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## CaptainBob (Jan 3, 2011)

Was the pressure regulator recently changed? If there is a water heater on the system the pressure regulator needs to have a thermal bypass built into it...


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## johntheplumber (Feb 11, 2013)

Did you say it was 20 years old?


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## CaptainBob (Jan 3, 2011)

Doubletap said:


> T&P is leaking (high pressure and no expansion tank)
> I replace pressure regulator & T&P
> I advise customer that expansion tank may be required. They say no just fix leaking T&P.
> Next day T&P is leaking. Pressure is 80psi. No excessive heat. So I replace T&P with 175psi T&P. Still leaking. The customer wants to know why 20 year old water heat requires an expansion tank it never needed before. My question is "if I install an expansion tank am I going to fix it?"
> Note: water heater is noisy


Ok, I see you did replace the regulator...


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## CaptainBob (Jan 3, 2011)

Adding a expansion tank would take care of the problem...or changing the pressure reducer to one that has a thermal bypass in it


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## Doubletap (May 5, 2010)

"Thermal bypass" on a PRV no kidding I've never heared of it I guess I need to take a look at Watts sight. I have been just grabbing a 25 AUB forever but this one of the smaller regulators I didn't even look at the number. I just matched it.


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## gitnerdun (Nov 5, 2008)

Did you put a pressure gauge on the drain and get the heater to start heating? That will cause the pressure to rise fairly quick if it is a closed system. I ran into this once and could only assume there was a check valve in the meter. I prefer, and installed, a pressure relief valve outside on the house side of the main shutoff.


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## CaptainBob (Jan 3, 2011)

gitnerdun said:


> Did you put a pressure gauge on the drain and get the heater to start heating? That will cause the pressure to rise fairly quick if it is a closed system. I ran into this once and could only assume there was a check valve in the meter. I prefer, and installed, a pressure relief valve outside on the house side of the main shutoff.


Still need a relief valve on the water heater, that's what he's having trouble with...


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## CaptainBob (Jan 3, 2011)

Doubletap said:


> "Thermal bypass" on a PRV no kidding I've never heared of it I guess I need to take a look at Watts sight. I have been just grabbing a 25 AUB forever but this one of the smaller regulators I didn't even look at the number. I just matched it.


Yep...make sure you get one with an integral bypass for thermal expansion...otherwise after 20 years I don't know what the heck else it could be...


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## gitnerdun (Nov 5, 2008)

CaptainBob said:


> Still need a relief valve on the water heater, that's what he's having trouble with...


The reason the TP is leaking might be from water expanding as its heated. It can't go anywhere if there is no expansion valve or tank. Does the TP leak all the time, or just when the tank is in the process of heating water?


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## Doubletap (May 5, 2010)

Looks like it only leaks during heating


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## CaptainBob (Jan 3, 2011)

130 PLUMBER said:


> sounds like you have a close system


What he said^^




CaptainBob said:


> Adding a expansion tank would take care of the problem...or changing the pressure reducer to one that has a thermal bypass in it


What I said^^


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## jitr64 (Sep 30, 2010)

An expansion tank will fix the problem ,just put a gauge on a hose bib turn thermostat up slightly to make heater fire up and watch the gauge go up it doesn't take long,show the customer as you do it.Print out some material on thermal expansion to educate customer.Some city meters now have built in checks or a check installed right after meter .Do you know what the city pressure is on that street ? we have some areas in excess of 200psi.


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## johntheplumber (Feb 11, 2013)

Also, don't forget that expansion tanks come pre-charged to like 40psi. You need to know the pressure to the house then add pressure to the tank as needed.


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

Doubletap said:


> T&P is leaking (high pressure and no expansion tank)
> I replace pressure regulator & T&P
> I advise customer that expansion tank may be required. They say no just fix leaking T&P.
> Next day T&P is leaking. Pressure is 80psi. No excessive heat. So I replace T&P with 175psi T&P. Still leaking. The customer wants to know why 20 year old water heat requires an expansion tank it never needed before. My question is "if I install an expansion tank am I going to fix it?"
> Note: water heater is noisy


Question 1: why replace a t/p on a 20 year old heater? They should be advised that it's time for a new heater. 

2: it's your job as the hired professional to tell them what needs done.. If they don't want it done properly with an expansion tank, then no warranty..here sign ticket.. If they refuse leave and don't do anything. 

Now your in this f'd up situation because you let a customer that doesn't know squat about plumbing, tell you how to do your job. 

I don't have these problems because I handle these things properly. 

I would tell customer they need a new water heater with an expansion tank. Now that you've depressurized a 20 year old water heater and now the customer had invested probably hundreds of dollars in a 20 year old water heater... Well good luck.


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

Doubletap said:


> Looks like it only leaks during heating




ITS THERMAL EXPANSION! you let the customer tell you how to do your job!


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## Jason1 (Nov 10, 2011)

im with johntheplumber... 20 years old? im just a noob apprentice, 20 years old? couldn't the noise be too much sediment in the bottom of the heater, that might create more pressure in the tank. wouldnt it?


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## stecar (Mar 18, 2012)

I agree with adding the exp tank. Had the same situation last week. I dont have the answer as to why it lasted so long without it ever blowing off. I added the tank and customer doesnt have any problems. 
As far as the 175 psi relief, on a newer heater, I believe it voids the warranty.


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## JoshJ (May 10, 2012)

Doubletap said:


> T&P is leaking (high pressure and no expansion tank)
> I replace pressure regulator & T&P
> I advise customer that expansion tank may be required. They say no just fix leaking T&P.
> Next day T&P is leaking. Pressure is 80psi. No excessive heat. So I replace T&P with 175psi T&P. Still leaking. The customer wants to know why 20 year old water heat requires an expansion tank it never needed before. My question is "if I install an expansion tank am I going to fix it?"
> Note: water heater is noisy


80 PSI and not heating. Now suppose over 20 years there has been a buildup of minerals on the thermostat, it now does not sense when it is up to temperature when it should, and keeps firing, causing overheating, which trips the TnP. 

Just throwing that out there as one hypothetical reason why there is a problem now, and there was not before.

At any rate, on a 20 year old tank, I would be strongly advising replace. 

Water heater being noisy when firing? Sediment on the bottom, which means it's superheating the water that's trapped in the sediment, which means, it's time for a new tank.


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

JoshJ said:


> 80 PSI and not heating. Now suppose over 20 years there has been a buildup of minerals on the thermostat, it now does not sense when it is up to temperature when it should, and keeps firing, causing overheating, which trips the TnP.
> 
> Just throwing that out there as one hypothetical reason why there is a problem now, and there was not before.
> 
> ...




Your information is incorrect... You say minerals build up on the t-stat which causes it to not read the tank temp properly which then causes overheating..

The t-stat reads the temp with a disc that expands and contracts to the desired set temp. The t-stat is on the OUTSIDE of the tank and reads it by resting against it (the tank). 

Take a electric t-stat and flip it over to the back.. You'll see a hole in the metal with a disc inside.. Take a nail or something and pole through the hole pressing against the disc.. If you press hard enough the safety,reset, Eco whatever you wanna call it, trips. That is set to trip based on high temps expanding that disc to the point where it trips the reset. There is nothing inside the tank that reads temp. 

The noise could be either scale build up on the elements or it could be low density elements.. Ever noticed how some elements are only a U shape and others are a U shape that curls back to the nut of the element? One is a low density element and one is a high density element. One is quiet one makes noise when it's running.


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

stecar said:


> I agree with adding the exp tank. Had the same situation last week. I dont have the answer as to why it lasted so long without it ever blowing off. I added the tank and customer doesnt have any problems.
> *As far as the 175 psi relief, on a newer heater, I believe it voids the warranty*.




Correct.. Bad idea.. Now you have even more pressure building in a 20 yr old tank that you have depressurized multiple times now. 

You should install a new tank and credit the price of the attempted repair.


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## johntheplumber (Feb 11, 2013)

Did he say it was electric?


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

I'm pretty sure.


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## JoshJ (May 10, 2012)

johntheplumber said:


> Did he say it was electric?


x2

Almost everything out here is gas, see electric like once a year, maybe. So I automatically think gas, unless someone specifically says electric.


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## theplumbinator (Sep 6, 2012)

stecar said:


> I agree with adding the exp tank. Had the same situation last week. I dont have the answer as to why it lasted so long without it ever blowing off. I added the tank and customer doesnt have any problems.
> As far as the 175 psi relief, on a newer heater, I believe it voids the warranty.


Not only would changing the t&p to a higher temp/pressure void warranty, it also takes liability off the manufacturer and puts it on you if the tank ever reached catastrophic failure. That's what the prosecutor will be saying during a criminal trial for negligence. Bad idea always! The tank came with a 150psi for a reason.


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## pdxplumber (Nov 21, 2009)

Why would anybody dump any money into a 20 year old water heater?
Why EF around with this. Check the pressure and replace the regulator if it's not working, replace the water heater and add an expansion tank. Done and done. 
This is not a conversation you can realistically have with the homeowner. Most plumbers don't even understand thermal expansion. I will walk from these jobs in a second if people don't trust me. Not worth the risk.


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## theplumbinator (Sep 6, 2012)

I dont understand how people dont understand thermal expansion either... [email protected]#$%^& 7th grade science. But half of them dont even know where their water heater is in their own basement ::shaking head::


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## alberteh (Feb 26, 2012)

Hey, if it works and does its job year after year with no complaints its easy to forget it even exists.

just sayin.


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## JK949 (Mar 18, 2009)

First off, gas or electric? I didn't see your answer.

Does it sound like popping corn or rumbling? That's sediment. 

You don't have to wait until a tank leaks to change it.


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## TallCoolOne (Dec 19, 2010)

Doubletap said:


> T&P is leaking (high pressure and no expansion tank)
> I replace pressure regulator & T&P
> I advise customer that expansion tank may be required. They say no just fix leaking T&P.
> Next day T&P is leaking. Pressure is 80psi. No excessive heat. So I replace T&P with 175psi T&P. Still leaking. The customer wants to know why 20 year old water heat requires an expansion tank it never needed before. My question is "if I install an expansion tank am I going to fix it?"
> Note: water heater is noisy


20 years old would be a miracle in my area, oldest one I have seen is 15 years old.

I would replace water heater or walk the job


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