T&P Valve Keeps Opening

If your T&P valve keeps opening, it could be a sign that your water heater needs attention. In this article, we address that issue, demonstrate how the valve works, and explain how to open the pressure relief valve on a water heater. Before we get into all that, let's answer the most basic question of all:

What Is a T&P Valve?

Often referred to as a pop-off valve, a T&P valve helps manage temperature and pressure in the water heater. It functions by automatically popping open (hence pop-off) and draining hot water from the tank to reduce temperature and pressure. This is why people call it a water heater pressure relief valve (or pressure reducing). Technically, this is incorrect. A PRV is what you install on the mainline supply to the house. T&P valves are for the water heater.

Why Does the T&P Valve Keep Opening?

Hopefully, it's open because it's doing its job. It's supposed to open to relieve pressure in the tank when necessary. If this is happening with frequency, you should consider lowering the temperature. If that doesn't seem to make a difference, you may have a compromised T&P valve. There are two things you want to look for:

Is it leaking rather than "popping" open to drain? Hard water can cause the internal components to seize up, creating a leak. It can be hard to detect this sort of leak if you are draining the T&P valve right into a pipe, so if you have that setup, try to be extra observant.

connecting a t&p valve directly into drain pipe

The pressure in the tank can wear the valve down, and what you'll see is the T&P starts popping open at lower and lower temperatures. You may not have hard water in your area, but every water heater tank introduces pressure into the equation. This issue is an eventuality.

In either case, you're going to need a new valve. Check out our guide on how to replace a T&P valve. Here are a few great replacement valve options:

Watts 100XL-4 3/4" standard T&P
Watts L100XL 3/4" long-shank T&P (for water heaters with insulation)
Jones J34980 3/4" top-mount T&P

How to Open the Pop-Off Valve Manually

Chances are you might've been tempted to hit the trip lever you see on the valve. You're on the right track, except you want to be clear of the valve once the hot water starts gushing out. Give the trip lever a quick flip and get out of the way.

Learn More About Water Heaters

We have tons of helpful resources here at PlumbersStock. Check out our water heater tutorials, or contact us with any questions. Remember, the water heater is the key to comfortable showers and effective appliances. If you are in need of repair, we have high-quality replacement parts. We proudly partner with the best names in the industry, like Bradford White, for example.