See steam coming out of your boiler and wondering what’s causing it?
Well, it depends on where the steam is coming from:
Let’s take a closer look at what the pressure relief valve is and what you should do if it starts letting out steam.
Need help right away? Give us a call, and we’ll quickly send over one of our certified plumbers to fix whatever is causing the problem.
Your boiler’s pressure relief valve (often called a “safety valve”), is a safety mechanism that sits on top of the boiler and helps maintain proper pressure levels inside your boiler.
Diagram of a condensing boiler’s pressure relief valve and the pressure relief drain (marked by red asterisks). Image source
If steam is coming from the pressure relief valve or the pressure relief drain, you likely have 1 of 2 problems:
Let’s take a closer look at both of these problems.
Your pressure relief valve is designed to open and discharge water when pressure levels inside the system reach dangerous levels.
When the pressure inside the boiler hits a certain level, the valve opens automatically with a pop-action lid and lets out steam/air that’s discharged to the bottom of the boiler via the pressure relief drain. The valve then recloses when the pressure drops to a safe level.
The good news? If you’re seeing steam/hot water at the bottom of your boiler, your safety valve is doing its job. The bad news? You likely have higher than normal pressure levels in your system.
So what causes high pressure? Usually, it’s 1 of these 4 problems:
First, you’ll want to determine whether the problem is actually high pressure levels OR a bad pressure relief valve.
Follow these steps to check your boiler’s pressure levels:
BUT if your pressure levels look normal, you may have a faulty pressure relief valve...
The problem may not be with your boiler’s pressure levels, but rather with the pressure relief valve itself. Over time, these valves can malfunction due to normal wear and tear. They may open up more frequently or may not seal properly, which could result in discharged steam even when pressure levels are normal.
So, if you see steam from the pressure relief valve and drain but the pressure levels on your boiler are normal (or lower than normal), then you likely have a bad pressure relief valve and will need a professional to replace this valve.
Contact MSP to schedule an appointment with one of our heating professionals. We’ll send over a heating expert ASAP so your boiler can run smoothly again.
Visit our boiler repair page to learn more about boiler repairs and how to schedule an appointment with one of our service pros.