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qwasert, Plumber
Category: Plumbing
Satisfied Customers: 543
Experience:  Journeyman Plumber
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How do I stop my water heater (gas) overflow pipe from constant

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How do I stop my water heater (gas) overflow pipe from constant dripping?

qwasert : Hi, Welcome To Just Answer. My name isXXXXX will do my best to help you figure out your problem or the best course of action.
qwasert : How are yo today?
qwasert : Is it the valve in the side or the top of the water heater tank that is dripping? It has a small lever handle on it?

The valve on top of the water heater


Excuse me. The side.

qwasert : There could be a couple of reasons this valve is leaking. 1) the pressure reducing valve in the house has gone bad. 2) the valve on the tank is warn out and needs replaced. 3) The water in the water heater is exceeding 210 degrees or 150 psi. I recommend buying a pressure gauge and putting it on the drain of the water heater to test the house pressure. On the valve there should be a tag that says the max pressure that valve is rated for.
qwasert : You have a couple of options at this point, if the house pressure is above 150 yet below 170, you can get a new valve for the water heater rated for higher pressure or install a house reducing pressure valve to get the house pressure into a more normal range around 60-75 psi.

Well, that didn't get me very far. This was a brand new installed water heater and my old one never did this.

qwasert : It is possible that the old water heater had a higher pressure relief valve.
qwasert : First thing I would do is test the water pressure in the house. You may need to install a pressure reducing valve or replace an old malfunctioning one if you do already have one installed.

It was a 50 gallon tank where this one is 40. Should I call a plumber?

qwasert : With it being a new water heater the water pressure in the house is most likely exceeding the safety rating of the valve. The plumber should have checked that for you.

So, now what?

qwasert : You can buy a pressure gauge for about $10 at any hardware store that will have a female hose end that will screw onto the bottom drain of the water heater. You can see what your pressure is and that will give you a better idea of what's going on. You definitely want it below 150 psi but a safer range would be closer to 60-75 psi. If it is high you will need to have a plumber come install a pressure reducing valve.
qwasert : This will keep the relief valve from dripping as well as save you from any future pipe bursts that can cause major damage to your house. If the relief valve is stuck open it may need to be replaced as well once your pressure is back at a safer level.
qwasert : Standing By. Can you think of any more questions at this time?

I do not see any gauges on the heater. There is a knob for adjusting water temperature & it is low. This can be fixed & should not cost $600?

qwasert : The water heater itself does not have a pressure gauge. It only has a tempature setting and a safety valve that is already leaking. You need to purchase a pressure gauge from a hardware store to test the water pressure to the house. This can be fixed and it should not cost $600. A new T&P valve for the water heater runs about $15-$20 and a pressure reducing valve for the house is about $65-75. Keep in mind that these prices are parts only, extra labor if installed by a professional.

What is a reasonable labor charge?

qwasert : Where I'm from labor rate is $60 an hour plus a service call of $50. It all depends on how long it takes to do the job. Generally an hour to install a pressure reducing valve and 30 min to replace a T&P on a water heater.
qwasert : Standing by.
qwasert : Can you think of anything else at this time? You will receive a link back to this chat from you're email should another question arise.
qwasert : I would get a second quote for a pressure reducing valve to drop the city water supply pressure down.
qwasert : We generally charge 175 to 250 to do that.
qwasert and other Plumbing Specialists are ready to help you
Hello, I just wanted to check back with you and see if you had any more questions about you're water leak. Please don't hesitate to ask.
Hello, just checking back to see if you have gotten you're water leak taken care of and if you have any more questions let me know.
Customer: replied 4 years ago.

I took out the pressure relief valve & installed one with 150 PSI. Now, it leaks (or overflows) only when I use hot water. I just tried turning down the heat adjuster to normal. Pressure from city is 100PSI and I have a pressure relief valve that is 150 PSI. This is a gas tank. Should it leak.

Hi again. No the tank should not leak during use. Is it still leaking from the valve in the side? If you replaced the pressure relief valve with a brand new 150 psi, and it still leaks you may have a defective valve or there must still be to much city pressure. How did you check the city pressure? Remember this is a safety device and you should never put a plug in it to keep it from leaking. If you're plumber recommended a whole house pressure reducing valve I would think to take that advice as I have not inspected your individual situation personally. I understand the other plumber was expensive however you can get a few bids to do the job and have them check you're water pressure most plumbers will give you a bid for free.
Customer: replied 4 years ago.

I checked the water pressure by putting a gauge on the hose spigot where water comes into house.

Does you're water heater have a thermal expansion tank on it?
Customer: replied 4 years ago.


I turned the adjustment to normal last night & showered and nary a drop. Might that be the answer?

If its not leaking now you should be good to go. I'm guessing the water heater temp was to high.
Customer: replied 4 years ago.

Well, it leaked last night, just about twenty drops and this am when I shaved it is still leaking & I do not have "hot" water to shave with.

Now what???????

You may need to install a thermal expansion tank. There is available a 175 psi pressure valve you can install on you're water heater, this would be available at a plumbing supply house for about $18. If that still doesn't work you are going to need to install a whole house pressure reducing valve. City water pressure can fluctuate depending on use and demand. It could be going above the 150 threshold of your current p&t valve.

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