You are currently viewing Should I Test My Hot Water Tank Temperature & Pressure Relief Valve (T&P Valve).

Should I Test My Hot Water Tank Temperature & Pressure Relief Valve (T&P Valve).

Should I Test My Hot Water Tank Temperature & Pressure Relief Valve (T&P Valve)?

Temperature & Pressure Relief Valve (T&P Valve) 

The answer is YES. In addition, it should also be done on a yearly basis.

Here is some information that you should know about the T&P valve on your hot water tank. If you should look at your hot water tank, you will notice a brass valve with a small handle. These are generally located on the side or on the top of your hot water tank. This valve is known as the T&P valve, which means, temperature and pressure relief valve.

How Does A T&P Valve Work?

The purpose of a T&P valve is to open and allow water to flow out of the tank in the event of malfunctioning. This is done automatically by releasing excessive temperature and pressure from the tank.

The hot water tank is a closed system and during the process of heating, will generate thermal expansion. This is the result of heating liquid inside a seal cylinder or container. So, customers should be very careful if they find themselves working around the water heater. In other words, the T&P job is to prevent your water heater from exploding or possible damage to your home.

A little expansion is normal, but too much expansion is unsafe. This is why if the temperature reaches 210 degrees or the pressure reaches 150 psi in the tank, the T&P valve will open. However, should this occur and is in contact with the human body, you could receive a third-degree burn and will require immediate medical attention. Customers should ensure the contractor doing the installation, piped the T&P valve outlet down to the floor or within 12″ above floor. This is to have control over the flow of water, should the valve open up.

How to Test Your Water Heater T&P Valve.

  1. Open the hot water tap and leave it running for 30 second to 1 minute then turn off the tap. This is to relieve the pressure in the tank.
  2. Place a bucket underneath the T&P pipe outlet to catch the water being released. 
  3. Gently raise the testing lever on the relief valve to release the pressure. Be careful, the water will be hot.
  4. Let the water drip out for a few seconds and then lower the valve lever again with caution (using force can damage the lever). You should hear water discharging out of the relief valve drain line.
  5. Close T&P valve lever and monitor drain pipe to ensure there is no continuous dripping. 
  6. Note: The drain line may be warm, which is normal.
  7. Empty contain with water, map the area and repeat the process again within 6-months to 1-year.

NOTE: The T&P valve is rarely used, therefore mineral build-up can cause it to not work properly over time. This is a safety hazard because, in the event of a temperature or pressure spike, the T&P valve may not open which could cause the water heater to explode.

So, should I test my hot water tank temperature & pressure relief valve (T&P Valve)? Contact the professionals here at Knowledge HVAC & Refrigeration and we will guide you on what to do.