In this article, we’ll learn how to quickly solve that small leak we might have coming out of our temperature and pressure relief valve on our water heater.

Whether our valve is located off the side which is the most common or off the top these steps will be the same and approachable by any homeowner. We'll go through a two-step troubleshooting process. The first step has no tools and hopefully this will get the problem solved but if it doesn't we’ll see the internals of a temperature pressure relief valve and how it actually works which will better inform us to help troubleshoot our situation.

1.   Flushing the valve

Step one is super simple. To stop the leak all we're going to do is try to exercise the relief valve by pulling on this lever. When we pull on that lever we should get flow of water so make sure we have a five gallon bucket.

For us, flushing doesn't look too promising because we’re not getting any flow when I actually open up the valve and move the lever. If we look internally a small rod goes to the seal that goes against a seat and then a spring presses that seal down. This spring is actually what controls how much pressure it would take to overcome the force on it and that is associated with the setting of 150 psi on this valve. If the internal pressure is past 150 psi that would be enough to actually force that spring to compress and then open up a path for this water.

Now if we have a small leak there is a good chance that there might be a little sediment caught between the seat and the seal. If we could flush that loose and get the sediment out then hopefully that seal can sit against the seat and our leak would stop. So flushing it out is our first step to try to get things to seal back up and stop our overall leak.

These valves also have a temperature part. The white probe is associated with a 210 degree fahrenheit set point which means that this probe will expand at 210 degrees fahrenheit. We open up the valve ensuring that the water inside the water heater cannot get to 212 which is the boiling point. It'll expand out, open up that seal and then allow water to flow out of the tank.

2.   Replacing the valve

If the flushing did not work, we've got to go into step two and that is to actually change out the valve. Turn off our cold water supply, turn down our temperature setting all the way to the lowest setting to make sure the burners won't turn on. We're going to connect up a garden hose to our drain valve and then run that hose outside.

One key part of draining is we have to make sure we're not pulling a vacuum where nothing's going to come out of the tank. We just loosen up the fitting on the hot water side and allow air to enter the tank which then should start to drain the tank. Here we drain into a five gallon bucket so we know how many gallons are drained out because we’re looking to drain out at least 10 gallons. So now with the water level below the port for the t&p valve, we can remove it without an issue of water coming out of that same port. Don't forget if we opened up our hot water side to make sure that we could release that vacuum and actually drain down our water here, tighten that back up. We don't want to forget about that and turn our cold water back on and start pressurizing the system heating up the water. If we have a loose fitting over here so just go ahead and tighten that up.

Now we're going to remove the actual valve itself. This specific unit is about 18 years old so it's already put in a good service life. Once we remove that we'll see the amount of sediment which is really caked up and that's what wasn't allowing the valve to open up or water to come out of the valve. So we go ahead and cut it open.

We have the shaft or the plunger that expands out and will open the valve if it's past 210 degrees fahrenheit and then inside is where that seal actually would seat down. So if I move the lever we don't see anything open up and that's because sediment has built up in there where there is no longer a passage for water flow. That is why it's important yearly to exercise our temperature and pressure valve, make sure we flow water out of there and ensure we don't get buildup like this.

Do not just push sediment that we want to clean out back in the tank as it could gum up our drain valve later on. With the vacuum cleaner pull that sediment and debris out and then with the finger slowly work it out of the threads. Just do multiple cycles working that out back and forth until they're clean.

Then we’re going to match up our old valve. It's a two and a half inch shank. Most of them are standard but we want to make sure it's a 150 psi 200 degrees fahrenheit which is the same as our old valve. So once we’ve confirmed that our new valve also is a 150 psi and 210 degrees fahrenheit we're ready to install.

Make sure to put a nice wrap of teflon tape in the clockwise direction and then we'll go ahead and thread that back into our water heater carefully. Once it's hand tight we'll go ahead and tighten that all the way down with a driver.

So now we have our new temperature and pressure relief valve installed and want to get the system back up and running.

First we'll make sure to turn on our cold water supply. Make sure we tighten up the hot water side where we allow air to enter so we don't pull a vacuum when we are draining the tank. Make sure the drain valve is closed. Then we reinstall the actual drain line to our temperature and pressure relief valve.

Now after that we do a little test run. Open up this new valve, allow water to flush out of it and then ensure that it closes completely with no leaks like we had before. Also turn the temperature dial to the previous setting where our temperature should be at about 120 degrees fahrenheit to 125 degrees fahrenheit depending on who's in our house. If we have little kids do be cautious we really don't want to crank that up or we could have a scalding hazard. So we want to let the water here come up to pressure and for the hot water to flush out all the air in our lines. Make sure we're getting hot water for our different fixtures and then just check for leaks. We didn't only touch the temperature and pressure relief valve so make sure there's no leaks anywhere else to ensure our problem is actually solved.