Temperature/Pressure Relief Valve Installation Mistakes And Increased Risks Of Water Heater Explosions

Posted on: 27 February 2017

If you intend to heat your home with a water heater, it is important to be mindful of the Temperature/Pressure Relief (TPR) valve. This is because this valve plays the important role of protecting a water heater from explosions. It does this by preventing the unnecessary buildup of pressure that usually occurs as a result of thermal expansion.

Installation mistakes can cripple the functioning of this valve. And when this happens, it exposes a the tank to risks of explosion.

A blocked test lever

A test lever is used to manually open the TPR valve. This comes in handy when testing whether the valve is functioning properly. It also acts as a safety guard in case the TPR valve malfunctions. In such a case, pushing the test lever will open the valve, allowing for excess pressure release, something that will then keep the water heater from exploding.

Poor water heater placement can lead to this lever's movement getting restricted by a wall. Adjacent fixtures can also end up blocking this lever. And since the lever is directly connected to the TPR valve, this blockage is bound to cripple the valve's ability to prevent boiler explosions.

When installing your water heater, make sure that the test lever has enough room to move. Occasionally testing its range of motion is recommended if you want to ensure that your heater's TPR valve isn't crippled.

Poor discharge tube installation

A discharge tube helps guide any hot water and steam that is emitted by the TPR valve. This helps to reduce scalding risks. It's also useful when it comes to preventing water damage that may occur as a result of uncontrolled water drips.

Discharge tube installation mistakes usually increase the risks of a boiler explosion. For example, piping the tube upwards instead of downwards decreases the tube's drainage effectiveness. It encourages water to accumulate around the TPR valve's opening, something that then increases mineral accumulation. This eventually blocks the valve, reducing its capacity to prevent boiler explosions.

Using a valve whose diameter is smaller than the valve's opening also increases explosion risks. This is because such a tube restricts the effectiveness with which the valve gets rid of excess steam and water. Any pressure buildup that results from thermal expansion will therefore not be released as effectively as it should, something that then puts your water heater under the risk of explosion.

Installing the discharge tube in such a way that it empties water to a hidden location is also a mistake. This is because it makes it almost impossible to notice TPR valve leaks. And since TPR valve leaks are a common symptom of thermal expansion, this makes it hard to not only detect but also to fix the underlying problem in time. This puts your water heater under the increased risk of an explosion.

When installing the discharge tube, make sure it is piped downwards. Also, make sure that you choose a discharge tube that has the same diameter as the opening of the TPR valve.

For more tips caring for your water heater or boiler, contact an HVAC contractor.