Why Is My Boiler Losing Pressure?

Why Is My Boiler Losing Pressure?

 

Low boiler pressure is a major cause of malfunctioning boilers. Leaks and other problems with the boiler can cause the pressure to drop over time, leaving you without hot water or heating. 

 

There are several reasons why your boiler may be losing pressure. This post covers why your boiler may be losing pressure, how to check whether it’s too low, as well as how to fix it. 

 

At J.Wheatley Gas, Plumbing & Heating Ltd, you can find expert gas engineers for boiler repairs or replacements. Contact us if you’re feeling unsure about why your boiler may be losing pressure and we can have an expert sent out to examine the situation. We operate across Driffield, Scarborough, Hunmanby, Filey and Bridlington. 

Boiler Pressure Explained

Though much of your central heating system is water-based, modern boilers don’t need a water storage tank like older-style systems. An expansion vessel replaces the header tank. 

Once your boiler warms up the system water, the pressure fluctuations of the water are absorbed by the expansion vessel. This is because the volume of water grows and decreases based on the temperature. 

Boilers need a certain operating range to function effectively and safely (0.7 bar & 2.5 bar). Some systems may have a filling valve to restore pressure if it drops below the predetermined limits. 

How to Check If Your Boiler Pressure Is Low? 

The pressure gauge and other indicators on the boiler's control panel will tell you whether the boiler has lost pressure. To know whether the pressure in your boiler is too high, too low, or just right, you can check the pressure gauge. You should review your boiler's handbook to find out whether the specific fault code you're seeing is related to low boiler pressure. 

 

If your boiler has lost pressure and the digital indicator shows less than one bar, you need to get it serviced. If the pressure has exceeded the ranges provided in the manufacturer’s handbook, the boiler could be unsafe. 

What Causes a Boiler To Lose Pressure?

The most common causes of a loss of pressure in a boiler include the following: 

• A leak in the system, usually at the radiator valves or somewhere in the infrastructure
• Corrosion or loose pipes can lead to leaks which result in lower pressure

Ways to Fix Low Boiler Pressure? 

Calling out a gas engineer for a boiler replacement or repair is the safest option. However, some people have opted to use a filling loop to increase their boiler pressure whilst they wait for engineers to come. 

The filling loops have isolating valves on each side with a handle valve and a bendable connection. Turn the isolation valve counterclockwise with a flathead screwdriver until the valve's line is perpendicular to the pipe. Next, open the water supply by rotating the handle counterclockwise. Close the handle valve and the isolation valve by rotating them clockwise after the pressure has reached the proper levels, as shown by the pressure gauge. 

If you’ve successfully increased the boiler pressure to normal levels, the error message will be gone and the water heater will function normally.