Using and Maintaining HVAC Systems in Rental Properties

Is a Leaky T&P Valve a Serious Problem?

Boilers and water heaters have several features in common, including the presence of a temperature and pressure (T&P) valve. This valve is a typical source of leaks on both appliances, and it's one that many homeowners may choose to ignore. A leaky T&P valve can make a mess, but it can also be a slow drip that's hard to notice unless you're looking for it.

T&P valves are safety features that prevent the internal pressure in your boiler from increasing too much. High pressure can cause internal damage to the boiler, affect other components in the system, or even create dangerous operating conditions. The T&P valve prevents these situations by releasing water or steam if the pressure passes a specific limit.

Why Is Your T&P Valve Leaking?

It's important to remember that the T&P valve serves a critical function on your boiler. If the valve is leaking, it may be operating correctly. High pressure in your hydronic heating system will trigger the valve, allowing steam or water to escape. In these cases, you'll notice drips as the valve does its job and relieves the excess pressure.

Depending on the design of your home's heating system, a dripping T&P valve may allow more water to enter from an automatic feeder system. The valve won't adequately address the high-pressure condition in these cases. Instead, the extra water will likely increase the system's pressure again, triggering the valve to release more water.

Another possibility is that the valve itself has failed. A failed valve can stick open or closed, and an open valve will drip water continuously. Many people immediately assume their valve must be at fault if they notice a constant stream of water. A failed valve in the closed position won't leak water but will still require replacement to ensure that your boiler can operate safely.

Why Shouldn't You Ignore Your Leaky T&P Valve?

You might want to ignore these leaks, especially if the leak is small and your system still produces heat. Unfortunately, this approach can be a costly mistake. A leaking valve always signals trouble. If the valve is in good condition, there's another issue causing your system to run with high pressure. In these cases, it's best to find and repair the underlying problem rather than ignore it.

On the other hand, a faulty valve can also be a significant problem. Your T&P valve is a critical safety component, and a stuck valve may not be able to open fully in an emergency. As a result, the valve will fail to relieve enough pressure, allowing the internal pressure of your boiler and hot water system to reach dangerous levels.

If you notice a drip from your T&P valve, you should contact a boiler repair technician. In most cases, the fix will be relatively cheap and quick, and you'll get the peace of mind that comes from knowing you've repaired a critical piece of safety equipment on your boiler.