Is your central heating system dropping pressure? You might have a hidden leak!

What happens if my boiler pressure is too low?

We’ve spoken before about what to do when your boiler pressure is too high, but what about when it’s at rock bottom? Low boiler pressure can cause issues in your central heating system if not treated, but luckily, there are some relatively easy DIY solutions that you can do to increase it back to a normal level.

In this article, we are going to run through what happens if your boiler pressure is too low, what the symptoms of low boiler pressure are and how low pressure can affect different aspects of your heating system.

What is boiler pressure?

Your boiler pressure is the amount of water in the heating system at one time. Too much water, and the pressure will be too high, but too little water, and the pressure will be too low. Your boiler will have a pressure gauge on the front that will tell you the pressure of the system.

Your boiler pressure should read between 0.5 and 1 bar when your heating is off, and 1 to 1.5 bars when your heating is on. Any lower than this, and you may be in some trouble.

What are the symptoms of low pressure in a boiler?

Aside from your pressure gauge reading below 1 (or 0.5 if your heating is off), there are some other tell-tale signs of low boiler pressure. For example, your radiators may not be warming up properly, or you may have no heating or hot water altogether!

Why is my boiler pressure too low?

There are a few issues that may be causing your boiler pressure to plummet, however the two main causes are that you recently bled your radiators and the air that was released hasn’t been replaced with water, or you’ve got a leak.

When you have a leak in the central heating system, the amount of water in the boiler reduces, causing the pressure to drop. In order to fix the leak and increase the boiler pressure, you need to find the source of it. 

The most obvious sign of a leak in the system is a puddle of water around the boiler. If your boiler pressure has significantly dropped and you haven’t recently bled your radiators, start checking around the appliance for any signs of water escape.

Faulty radiator valves can also cause leaks, so it would be worth checking around the bottom left or right of the radiator. If water is escaping, replacing the faulty valve should stop the leak and you will be able to top up your water pressure relatively easily.

A heating engineer will be able to fix the leak, or recommend upgraded equipment if necessary.

Is low boiler pressure dangerous?

The short answer is no, low boiler pressure isn’t dangerous, but this doesn’t mean it can be ignored. Low boiler pressure causes inefficiencies and can mean that you pay higher heating bills than you should.

Low boiler pressure can also have a drastic impact on the life of the boiler, and could mean that you have to replace your boiler much earlier than would otherwise be necessary.

How do I fix my low boiler pressure?

So, now that you know what low boiler pressure is, its symptoms, and why it could have dropped, you’re now probably wondering how you can fix it?

Once you’ve checked for leaks and determined the reason for your drop in pressure, you can fix the issue by adding more water to the system through the filling loops. If you can’t locate the filling loop, contact the manufacturer and enquire about your specific model.

How to add water to the heating system 

In order to keep safe, turn your heating off and wait for the water to cool down. Once cool, attach one end of the filling loop to the boiler, and the other to the mains water valve. Open both of the filling loop valves to allow new water into the system. If your boiler has an internal filling loop, you don’t need to attach it, just flick the switch on the valve to open it. 

  • Keep an eye on the pressure gauge and fill the system until the gauge reaches an acceptable level. 
  • Close both valves and turn your boiler back on. 
  • Some models may require you to reset them by pressing the ‘reset’ button. 
  • Undo the filling loop and store it in a safe place until you need to use it again.

If your boiler pressure continues to fall, call a heating engineer. They will be able to inspect the system, investigate the issue and advise whether you need to repair or replace your boiler.

How Harmuns can help

At Harmuns, we can locate the leaks your plumber can’t. If your boiler pressure is continually dropping and you think it’s a leak, but no one can find it, give us a call!

We will send an experienced, gas-safe engineer to your home to deal with the issue in the most efficient way. We use different types of detection equipment, such as moisture metres, thermal imaging and trace-gas systems to find the leak and fix the problem.

You may not need our services right now, but you could in the future. Save our number now to prevent future panic: 01753 378569

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About Harmuns

We are a specialist non-invasive pipe and water leak detection company here to fix your problems. We find hidden leaks on central heating systems, water mains and hot & cold water supply within the property.

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We are not an emergency plumber. If you have a visible leak, please contact your local plumber.