Low boiler pressure can happen to the best of us, but it is nothing to worry about and is fairly simple to fix.

Like everything else, boilers need our attention from time to time, and for your system to operate smoothly and efficiently, the pressure needs to be stable.

Our boiler is in charge of providing hot water to the radiators and the pipe system. That same hot water supply that circulates around the system is responsible for the heat that our radiators produce.

Since Combi boilers are an increasingly popular choice amongst UK homeowners and account for well over half of the new domestic boilers installed each year, we are going to walk you through the steps you need to fix your Combi’s pressure.

low boiler pressureHow to Identify Low Boiler Pressure

A sign of low boiler pressure is radiators that take longer to heat your space.

But, before you attempt to play around with any settings, you should first check to see if the pressure is low.

Luckily, this is an easy check because most boilers come with a water pressure gauge which you can find on the control panel.

Most gauges come in circular dials that have green and red zones on them to indicate the correct and safe level of pressure.

While the green zone shows the minimum safe pressure, the red indicates the maximum safe pressure.

The pressure is measured in bars, and most systems operate within the range of 1 to 2.

If the needle has fallen below the green zone, that is an indicator of pressure that is too low.

Main Causes of Low Pressure

Bleeding a radiator or water leaks somewhere in the system are the two major causes of low boiler pressure.

Before you decide to fix the pressure manually, you must check for any leakage.

Although you can’t inspect the hidden pipes, there are still signs to look for in order to identify and catch any water leaks before serious damage could occur.

Examine the pipes and the radiators for leaks or signs of moisture, but make sure not to mix up condensation with leakage.

Stains and damp patches on your walls with swelling in the skirting board should not be ignored either, as they could be signs of leakage.

If you find a leak, do not try to fix the pressure yourself and instead get in touch with a gas safe registered engineer who has the experience to repair the underlying issue.

low boiler pressureHow to Fix Your Low Boiler pressure

Every boiler is different, and each pressure system differs, so it’s best to check the manual to see if it is safe for you to re-pressurise it.

If you do not have the manual anymore, you should try to visit the brand’s website to find relative instructions or helpful tutorials.

A step by step guide to fixing the pressure on a Combi boiler.

1. Switch off your boiler

You must allow the boiler to cool down before you try to re-pressurise it. By letting it cool down completely you can rest assured not to come into contact with hot water or pipes.

2. Check the filling loop

Now check to see if your filling loop is attached at both ends. For those of you who do not know what the filling loop is, it is the pipe that connects your boiler to the water supply.

3. Open the valves

Once you have made sure everything is firmly attached on both sides, open the vales at each end. You should now hear the water flowing into your system.

More modern Combi boilers operate with a key, which is easily pushed into a tube with a plastic manifold with padlock symbols.

Line up the arrow on your key with the open padlock symbol and push the key inside, then turn it to the closed padlock symbol.

Now keep turning the plastic nut that is right next to the manifold that is holding the key. Keep turning the nut until you hear the water.

4. Watch the pressure

As water flows, the pressure will begin to rise, so make sure to carefully watch the needle on the gauge until it rises between 1 to 1.5 bar.

But, remember to check your manufacturer’s specific bar recommendation.

5. Close both valves

Once the gauge has hit the right recommended pressure, shut off both vales one after the other to stop the water flow.

Those who used an internal key should tighten the plastic nut again to stop the water flow.

6. Turn your boiler on

You can now turn your boiler on and if there is a manual reset button, make sure to press it. Take a few minutes to ensure that the pressure is stable.

7, Remove the filling loop

Undo and remove your filling loop if it is external. You may see some spillage, but do not worry because this is completely normal.

If you have tried all the above and have not been able to fix the low boiler pressure, then contact a boiler servicing company for further assistance.