Losing Boiler Pressure - Causes and Fixes

The good thing about boilers is that they don’t forget. They don’t lose the car keys 10 minutes after you should have set off from work, they don’t forget their wallets before impulse buying on Amazon and they don’t forget the national insurance number card you got when you were 16 and haven’t seen since. They do, however, lose pressure. 

Low Boiler Pressure greatly impacts performance and ends up costing you more because of it, and can very quickly lose the ability to adequately heat your home and offer you warm bubble baths. So how can you fix this, and what causes low boiler pressure to begin with? 

If your boiler keeps doing this, then it’s a good time to determine whether or not you’ll benefit from replacing the boiler and to get an idea of how much that might cost. We offer boilers, supplied and fitted, for free in the UK for eligible households – find out if you qualify here.

So, what is boiler pressure and why do you need it? 

Your boiler operates on what’s called a sealed system. Meaning that there’s a balance of water and air in the system and it needs to be at a good pressure in order to get the warm water around our house. 

If there’s not enough pressure in this system then when you’re trying to heat rooms, the boiler will have a tough time trying to push water to those areas. 

If there’s too much pressure then the water will rush through the system like a bad curry after 6 pints of lager. 

In the wise words of Thanos, “Perfectly balanced, as all things should be.”

If this isn’t your first rodeo with low boiler pressure and your boiler is less than 7 years old, consider fixing or replacing it. If your boiler is over 7 years old then it’s time to get it swapped out for a newer, more efficient boiler. We can help with that if you’re in the UK – find out how here. If your boiler is losing pressure more often than a human can birth out a baby, that’s a bad sign. 

If this is your first time though, then we’re happy to share this special moment with you. Let’s get it sorted.

    Boiler Pressure gauge

    What should I do if my boiler has lost pressure? 

    Like some humans, boilers work best under pressure, so let’s build that back up. Firstly we need to identify where your boiler pressure is, and where it needs to be. A boiler that is switched off should be around 1 Bar of pressure – there’s usually an obvious green section of the pressure gauge that identifies where this is. If you can’t see any gauges and there’s a flap at the bottom of the boiler, they’re behind the flap. There’s likely one for boiler pressure and one for water temperature, but you might have a fancy screen for temperature or a twisty knob (haha) instead. 

    Make sure nobody’s trying to run a bath or warm the radiators, you need the boiler switched off for this – if there’s a switch on the wall for it then give that a flick too. 

    Now, pressurising a boiler is pretty quick and simple and you can do it at home without any Gas Safe certification. Underneath your boiler should be either one or two taps, or you may have screws in which case you’ll need a tool that should have been provided with the boiler. 

    These taps indicate your filling loop. Make sure you can see both the tap(s) and your pressure gauge so you know when to stop. 

    If you have one tap, twist that (usually anti-clockwise) 45 degrees, you’ll hear water rushing through the pipes. If you have two taps, turn them both. If you can’t turn the taps fully then it should still add pressure but will take longer. If you can’t turn them at all then you’re going to need some tools. Unscrew the little screw that’s at the centre of the tap – don’t sweat, no water will come out. Now grab a pair of pliers once that taps off and try twisting with the pliers instead. 

    Once the boiler pressure gauge needle is in the green zone close the tap(s) off. You’re good to go now! Switch the boiler back on to double check – run the hot tap or stick the heating on. The pressure should go a little bit above the green zone when the boiler’s in use.

    Repeated Low Boiler Pressure, even after you’ve refilled it? 

     

    If your boiler is losing pressure faster than a 4 year old can throw their toys around the living room then something’s not right. 

    Could it be time for a replacement? We help UK homeowners get a replacement boiler, including installation, for free! Find out how here

     

    What could be causing repeated low Boiler pressure? 

     

    The most common issue is a leak in the system – this is all of the pipework and radiators between the ‘out’ pipe and the ‘in’ pipe on the boiler. All of those pipes that go around your home – there could be a leak anywhere, even in walls or under floorboards. This makes finding leaks pretty difficult. 

     Start with what you can actually see, and go around every room inspecting the pipes. Check for damp patches around joints and bends in the pipework because this is where leaks are most common. Check radiator bleed valves (typically at the top of the radiators). 

     If you can feel a wet patch then it’s a good sign. This means you know where the issue is, and you can call a gas safe engineer to come out and replace that bit of pipe or that joint. 

     If you can’t find the leaky pipe then it may be hidden from view, in which case you’ll have to call an expert to come and inspect it. Don’t just leave it, because if there is some water finding its way into an enclosed space in your house then something worse than a bad pipe will be growing there.

    The second problem could be a leak in the boiler. This is less common, but does happen. Components in the boiler degrade over time due to corrosion and general age. If you’re handy with these types of things, you could remove the cover from the boiler and carefully look for signs of leaking, but we’d really recommend you leave this to a professional. Employ the knowledge of a Gas Safe engineer. 

    To fix a leak in the boiler we’d recommend the same – hire a Gas Safe Engineer who can help. They’ll need to identify which component in the boiler is leaking because several parts could be the culprit. 

    At this point, it might be worthwhile just replacing the boiler. We help UK homeowners get a replacement boiler, fully fitted for free. Find out if you qualify here!

    The third issue could be a broken boiler part. Some people from a long line of secret wizards can sense issues within the boiler, but for us normal folk, we either use error and fault codes or we summon one of those gas safe wizards. The average repair cost for a boiler spans from around £300 to £500, so it’s always worth checking if you could replace the boiler for free. Check out if you qualify for a free boiler here. 

    Low Boiler Pressure Error Codes

    Remember that boilers can lose their pressure occasionally, it even happens to the best of brands. Here are some of the popular boiler brands and their error codes. 

     

    Ideal Boiler Pressure Loss

    Error codes indicating Ideal boiler losing pressure:

    F1 or ‘Water Pressure’ description on display.

    Pressure error codes applicable to: 

    Ideal Logic, Ideal Logic Plus, Ideal Isar, Ideal Vogue, Ideal Vogue Max, Ideal Mini

     

    Worcester Bosch Boiler Pressure Loss

    Error codes indicating Worcester Bosch boiler pressure loss:

    E2, A1, CE 207, H07, 224 V, 1017W, 2970 B, 2971 B.

    Pressure error codes applicable to: 

    Worcester Bosch CDi Classic, Worcester Bosch CDi Highflow, Worcester Bosch CDi Compact, Worcester Bosch Greenstar 25i, Worcester Bosch Greenstar 30i combi, Worcester Bosch CDi Classic Regular.

     

    Vaillant Boiler Pressure Loss

    Error codes indicating Worcester Bosch boiler pressure loss:

    E2, A1, CE 207, H07, 224 V, 1017W, 2970 B, 2971 B.

    Pressure error codes applicable to: 

    Worcester Bosch CDi Classic, Worcester Bosch CDi Highflow, Worcester Bosch CDi Compact, Worcester Bosch Greenstar 25i, Worcester Bosch Greenstar 30i combi, Worcester Bosch CDi Classic Regular.

     

    Baxi Boiler Pressure Loss

    Error codes indicating Ideal boiler losing pressure:

    F1 or ‘Water Pressure’ description on display.

    Pressure error codes applicable to: 

    Ideal Logic, Ideal Logic Plus, Ideal Isar, Ideal Vogue, Ideal Vogue Max, Ideal Mini

     

    Finally, if there’s no leak, there’s no problem. Topping up your boiler’s pressure manually is easy, free and most cases will do the job fine. 

    If there is a leak, get an engineer to diagnose the issue and plan your decision from what they come up with. 

    Hopefully we’ve helped raise your boiler from the dead for a while at least, now go and enjoy that bubble bath!

    Are you entitled to a Free Replacement Boiler?

    At Borthwick Heating we work with the UK Government to install free boilers to eligible UK Homeowners. To check if you qualify click the button below.

    Borthwick Heating Inuslation UK is a trading style of Borthwick Group (Energy) Limited Registered in England & Wales| Company No. 06753929 

    Borthwick Heating & Insulation are regulated by the Financial Conduct Authority. We are a Credit Broker and not a lender. We offer Credit Facilities from a panel of lenders. Borthwick Group (Energy) Limited is the full legal and registered trading name of all activities that advertise themselves as Borthwick Heating & Insulation and online as www.borthwickheating.co.uk

     

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