Some of the most common problems you will experience with your boiler is water pressure related – having no hot water, for example, how annoying! Well, good news – most of the time it is easy to diagnose, and you’ll be able put it right yourself. Our handy guide will talk you through the most common boiler pressure problems, the causes, and the solutions.
WHAT IS BOILER WATER PRESSURE?
Your boiler heats up cold water that flows through pipes and radiators in your home. For your boiler and central heating system to work as efficiently as possible, your water pressure needs to be stable. Your boiler requires a consistent water pressure between 1 to 2 bar to operate safely and efficiently (the indicator needle should be in the green section). In most common combination boilers, the pressure is maintained by one of three connections – a ‘filling loop’, ‘keyed filling link’ or ‘keyless filling link’. We’ll go into more detail about these later.
WHAT CASES LOW BOILER PRESSURE?
When finding the reason for a low water pressure there are two main suspects: Leaks, and bleeding radiators. If the water drops below 0.5 bar (the indicator needle in the red section), water has been lost from the system and needs to be replaced.
Leaks, no matter how small, in your boiler system if gone unnoticed for some time can lead to a drop in water pressure. You can take a look around your home for any damp patches around pipes and radiators. Only a Gas Safe registered engineer can open up your boiler to check inside for leaks. If you do find a leak, or need to top up your pressure regularly, it is best to give us a call and one of our Gas Safe engineers will come and help out.
When bleeding your radiators, you will hear a hissing sound. This is the release of air from the system, which lowers the water pressure in your boiler. If you have done this recently you might have noticed a drop in boiler water pressure.
HOW CAN I CHECK MY BOILER PRESSURE?
To find out if you have low water pressure you will first need check the pressure gauge that is often located on the front of your boiler. If you have a hydraulic pressure gauge, you’ll see green and red sections of the dial indicating high and low pressure. These are usually also numbered 1-3. If you see that the indicator is showing below 1 bar when not in operation, then your boiler will not be operating safely or efficiently. Water has been lost from the system and needs to be replaced using one of the three connections mentioned earlier. On most digital gauges, you’ll see a flashing pressure reading indicting low or high pressure.
If the pressure on your boiler is indicating high pressure, usually above 2.75 bar, then you will need a Gas Safe registered engineer to check the system and reduce the pressure down to 1.5 bar. High pressure can be a result of a fault inside your boiler that you’ll need an engineer to repair. High pressure in your boiler can result in costly repairs to your boiler and heating system and may also cause major leaks if ignored.
CAN I FIX LOW BOILER PRESSURE MYSELF?
Boiler pressure differs with each make and model of boiler. The best thing to do first is to check the manual to see if it is possible to re-pressurise yourself. There may also be instructions to the rear of the control panel. Please note that if removing this panel requires a tool, do not go ahead and remove it! You will need a Gas Safe engineer to do this for you. Top Tip: You can check the boiler manufacturers website or your boiler manufacturers manual, or even YouTube for video tutorials on how to top up your boiler.
HOW DO I TOP UP THE PRESSURE IN MY BOILER?
Re-pressurising your boiler means allowing more water into the system. This is done by one of three ways, but the most common of which is the ‘filling loop’. The filling loop can be found on the underside of most boilers and should have two valves at either side with tap handles (or flat-head screws on old boilers).
TOP UP YOUR BOILER PRESSURE USING THE FILLING LOOP
1 Switch off your boiler and allow it to cool for 30 minutes.
2 Ensure that both ends of the filling loop are securely attached.
3 Open both valves to allow cold water into the system (you will hear it).
4 Wait for the indicator dial to reach 1.5 bar and close both valves.
5 Once both valves are securely closed, switch on the boiler and reset the fault code, if needed.
TOP UP YOUR BOILER PRESSURE USING BAXI’S EASY FILL PERMANENT FILLING LINK
Please note: The diagram above is suitable for Baxi Boilers using a ‘keyless filling link’. For your particular make and model of boiler, you can check your boiler manufacturers manual.
HOW OFTEN SHOULD I NEED TO TOP UP THE PRESSURE IN MY BOILER?
The water pressure in your boiler system will usually need topping up once or twice a year. If you are having to re-pressurise your system more often, there may be a fault inside your boiler, and you will need to contact a Gas Safe engineer to find and fix the problem. More often than not if the pressure rises by more than 1 bar when using your central heating, then the expansion vessel may require re-pressurising.
DO I NEED TO CALL A GAS SAFE ENGINEER?
You do not need to be Gas Safe registered to increase the pressure in your boiler, but you should never attempt to fix the boiler yourself. It is illegal for you to work on gas appliances if you are not Gas Safe registered. If you are in any doubt about how to re-pressurise your boiler, or continue to have pressure problems, our expert Gas Safe registered engineers are on hand to help out, diagnose any problems, and repair them safely and legally.
COMMON BOILER LOW PRESSURE ERROR CODES BAXI, MAIN, POTTERTON
Error Code: E118 or E119. Depends on the model of your boiler.
The boiler will go into reset to try and rectify the problem.
Error Code: F1. Depends on the model of your boiler.
Error Code: F22.
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