A TPR Valve, or Temperature & Pressure Release Valve, is a safety device located on a water heater or boiler.
As indicated in its name, this apparatus is designed to release water if the temperature or pressure in a water tank exceeds safe levels. They are critical components of hot water systems and play an important role in ensuring safety.
Why Do I Need a TPR Valve?
When heat is added to water, the water vaporizes and expands. Expansion in an enclosed space, such as a water tank, leads to an increase in pressure.
Without a way to reduce the pressure in the tank, it could continue to build, eventually resulting in a water tank explosion.
Although they are rare occurrences, tank explosions have been known to happen with defective or poorly maintained TPR valves.
While some thermal expansion is normal, excessive expansion can become dangerous very quickly. This is why that a two-inch brass fixture is so essential for in-home safety.
When properly configured, a temperature and pressure release valve should release when the temperature reaches 210°F or 150 pounds per square inch (psi).
In addition to preventing drastic increases in pressure, these safety valves also help to regulate temperature. Modern water heaters and boilers have thermostats that are meant to set a maximum water temp.
But what happens when there is a faulty thermostat that does not properly regulate the temperature? What’s stopping scalding hot water from entering the home and potentially harming its inhabitants?
In comes the TPR valve to save the day, yet again! Once the temperature reaches 210°F or higher, the valve will open to release the heat and cool down the water.
Don’t Forget Your Discharge Pipe!
A discharge pipe must also be attached to the valve. As depicted in the picture below, this is a pipe that extends downward to within 6 inches of the floor. When a TPR valve opens up, it will expel scalding hot water and/or steam.
This is obviously a dangerous scenario for anyone who might be close by. So the discharge pipe must be attached in order to safely redirect the hot water downward and away from any bystanders.
One easy way to prevent water tank issues, is to stay on top of your maintenance. Manufacturers recommend testing the TPR valve at least once a year to ensure proper functionality and no leaks or defects.
Of course, you can hire a pro to take care of these maintenance tasks. But for the DIY enthusiasts out there, click here for a step-by-step guide on how to test your TPR valve.
Home Inspections – Putting the Microscope on TPR Valves
During our standard home inspections, we pay very close attention for properly maintained boilers/water heaters. We are always looking at TPR valves and discharge pipes. If either of these devices is missing or defective, we will be sure to recommend immediate repair.
Both city’s rental license programs make TPR valves and discharge pipes mandatory. (See Section 2.4 in the Denver Residential Rental Program Guidebook or Section 3 in the Boulder Rental Housing License Handbook.)
At Scott Home Services, it is our priority to help families live in safe, healthy, and comfortable homes. So whether it comes to inspecting TPR valves or any other aspect of the home, we are happy to be of service!
Chris Kimmel worked as an Associate Home Inspector for two years, handling numerous services including sewer scope inspections, pest inspections, mold air sample testing, radon testing, and water quality testing. Chris now works with Scott Home Inspection as a Content Writing Specialist.