What is the water heater pressure-relief valve and what purpose does it serve?

Year after year, your water heater serves an important role in your home. Your morning routine just wouldn’t be the same—or nearly as comfortable—without hot water. Yet, water heaters and their components do not last forever. Preventative maintenance is the key to ensuring that your water heater continues to safely provide your home with hot water. In this article, we’ll review a critical safety component of your water heater, the water heater pressure-relief valve. We’ll discuss what it is, what it does, and how to ensure it’s still working and protecting both your water heater and your home.

Too high of a temperature setting can also cause excess pressure in your water heater. Talk to your King plumber about what temperature your water heater should be set at.

What is the water heater pressure-relief valve?

The name is actually quite literal. It’s a valve that relieves excess pressure in the water heater tank. By doing so, it can prevent excess pressure buildup that has the potential to cause a tank burst and flood your home. It’s an unheralded but essential safety mechanism for your water heater.

What leads to excess pressure in the tank?

As your water heater heats up the water in the tank, the water expands and steam is generated. The greater the heat, the more expansion that occurs. This expansion puts pressure on the exterior walls of the tank, but this is to be expected. Some degree of excess pressure escapes through the water pipes connected to the water heater. In the event that it cannot, the pressure-relief valve triggers. By releasing some of the hot water and air, the valve lowers the pressure back down to safe levels.

For reference, the normal pressure of the water inside of the water heater tank is 50-100 PSI.

What can go wrong?

If the pressure-relief valve is unable to open, the pressure can continue to build inside of the tank past that 100 PSI ceiling. The heavy metal tank can withstand a lot of pressure buildup, but it eventually has its limits. The results are explosive, as the tank gives way, sending hot water flooding outward. If your water heater has an emergency shutoff valve installed, the burst will be detected and the water supply will automatically shutoff. If not, you’re potentially looking at a flooded home with significant and costly water damage.

So, what causes the pressure-relief valve to fail? In many cases, the valve gets stuck or frozen in place due to the buildup of rust and corrosion inside the tank. Or, the valve is stuck due to a prior instance in which it released hot water. A broken valve is something that should be fixed right away, but—unless you’re examining your water heater closely on a regular basis—may not be something most homeowners notice. That’s why regular testing and maintenance is important.

Testing the valve

We recommend that homeowners here in Chicago test their pressure-relief valve when they flush out their water heater twice every year. Bundling your water heater maintenance tasks together makes sense, since each of these tasks takes about 10 minutes to complete.

Start by positioning a large bucket underneath the valve. You are going to release some hot water during this process, so you want to make sure you’re wearing safe clothes to reduce a scalding risk. Remove the drain pipe attached to the pressure valve. Then, gently lift the valve switch so that hot water begins to come out of the valve and into the bucket. For the purposes of this test, don’t push the switch all the way up.

So long as water and air are coming out of the water heater during this test, your water heater pressure-relief valve is working as intended. On the other hand, if you’ve flipped the switch up and you’re not seeing any release, that could indicate a problem with the valve. You should call our plumbing team at King immediately for service so that we can diagnose the problem and replace the valve, if need be.

We’re here for your plumbing and water heater needs

This goes without saying, but if you’re not comfortable flushing your water heater or checking the valve, don’t just ignore this crucial maintenance need. Give our team a call and have us out to your home to perform this service for you. Remember, this preventative maintenance can help prevent a tank burst and major water damage.

0 replies

Leave a Reply

Want to join the discussion?
Feel free to contribute!

Leave a Reply

Your email address will not be published. Required fields are marked *