An Overview of Water Heater TPR Valve

The temperature and pressure release (TPR) valve must be sound for your water heater to operate efficiently and safely. Below is an overview of this critical water heater part.

What Is the TPR Valve?

Water expands when heated. As such, your water tank's pressure will increase if it overheats. Extreme temperature and pressure are dangerous since they can cause water to leak out of the tank, cause burn injuries, and damage your plumbing system.

The water tank has a temperature and pressure limit it can safely handle. If the temperature and pressure exceed this limit, the TPR valve opens to release some of the water and, hence, lower the pressure to a safe level.

For most tanks, the TPR valve sits on top or the side of the tank. A discharge tube connects to the valve to drain water the valve may release in case of extreme temperature and pressure.

TPR Valve Problems: Causes and Signs

The TPR can malfunction just like other parts of your water heater. In most cases, you can trace the malfunction to age-related wear and tear. For example, the valve has a seal that prevents water leakage at normal wear and tear. Over time, the seal might wear and allow water to leak out of the tank even at normal temperature and pressure.

Other things that can cause TPR valve problems include accidental damage and poor replacement. For example, a do-it-yourself TPR valve replacement that has gone wrong can allow water to leak out of the valve without cause.

Water leakage is the most obvious sign of TPR malfunction. However, a leakage doesn't necessarily mean that the valve has malfunctioned; it might also mean that the valve is operating as it should, and the tank's temperature and pressure are too high. No matter what the cause is, you have a TPR valve problem on your hands if it leaks without cause.

A faulty TPR valve might be stuck and fail to release water even at abnormal temperature and pressure. In such a case, the continued pressure increase might cause the tank to rattle as the high-pressure water seeks a way out. If you hear such rattling sounds, stop using your water heater until a plumber fixes it.

TPR Valve Maintenance

The best way to preserve the TPR's integrity is to inspect and test it regularly. A visual inspection should tell you if the valve is leaking water. However, such an inspection is not enough to detect a valve that cannot release water at high temperatures and pressure. You need to test the valve regularly for such evaluation.

Here are the general steps for TPR valve testing:

  • Disconnect the drainpipe from the valve
  • Lift the valve's lever to a moderate level
  • Check for water flow (you should have a bucket under the valve for this)

A plumber can also help you test the TPR valve. The valve is stuck if water doesn't flow out of it during the test, which means it should be replaced.