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Falling pressure, cold radiators, a cryptic code flashing on the display — most boiler trouble is a forecast you can learn to read in five minutes.
My boiler's stopped — where do I start? Check the gauge: below about 1 bar, top up once through the filling loop using your boiler's manual. Note any fault code on the display, try one reset, and if it won't come back — or the same fault repeats — ring 020 4577 2888 to be put through to a local plumber. If you smell gas, skip all of this: leave the house and call 0800 111 999.
One dip is weather; a falling trend is climate. Top up once through the filling loop — if it sags again within days, the system is losing water somewhere and wants a proper look.
Most sealed-system boilers sit happiest around 1 to 1.5 bar when cold — the gauge on the front gives you the reading, and your manual gives the precise range for your model. Dip below roughly 1 bar and the boiler sulks: lukewarm radiators, lockouts, sometimes a low-pressure code on the display. Repressurising through the filling loop is a legitimate job for most householders, done once or twice a year after bleeding radiators without a second thought.
What deserves suspicion is the pattern. Topped up last week and already sagging again? The system is quietly losing water somewhere — a weeping radiator valve, a joint under a floor, a pinhole you'll never spot from outside — and every top-up just refeeds the leak while adding fresh oxygen that corrodes the system a little more. A reading that sits high instead, past 2.5 or 3 bar, points the other way: a filling loop not closed fully, or an expansion vessel fault. Either direction, mention the actual number when you ring.
Five checks, two minutes, no tools: power, controls, pressure, condensate pipe, one reset. A fair share of "dead" boilers come back after this list.
If the list doesn't fix it, you've lost two minutes and gained a far better phone conversation, because you can tell the plumber exactly what you checked and what the display says.
It's the boiler's own shorthand for what hurt — and different makes speak different dialects. Write it down exactly; don't clear it and don't guess.
Every manufacturer runs its own code system, so the same jumble of letters and numbers can mean low pressure on one boiler and an ignition fault on another. The only reliable translator is your own boiler's manual — most are findable online with the model number if the paper copy vanished years ago. Codes broadly sort into themes: pressure and circulation, ignition and flame detection, fans and sensors, and condensate drainage.
Two habits help here. First, record the code before touching anything — a photo of the display, since a reset can wipe the very clue an engineer needs. Second, resist resetting over and over; one attempt is diagnosis, five is punishment, and a boiler that repeatedly locks out on an ignition or flame fault wants a professional, not persistence. Anything suggesting flame, combustion or gas supply is strictly look-don't-touch territory.
Leave the house now and call the National Gas Emergency Service on 0800 111 999 from outside. Not a plumber, not this line — that number, first.
A gas smell is the one situation on this page where reading stops and acting starts. Get everyone out of the property. On the way, touch nothing electrical — no light switches on or off — and no flames, no cigarettes, no ringing your phone until you're outside at a safe distance. Don't open up walls or go hunting for the source; that's the emergency service's job, and it runs around the clock.
Once the property has been made safe, then and only then does a plumber or heating engineer come into the picture for any repair work. Anyone working on gas appliances in the UK must be Gas Safe registered by law — asking to see the card is normal, not rude. This line is the right call for boilers, leaks and pipework; for suspected gas escapes it is emphatically the wrong first call, and we'd rather say that plainly than ever be dialled first in that situation.
Topping up once in a while is ordinary life with a sealed system. Topping up every week is a leak dressed up as routine maintenance — the water is going somewhere, often into a wall or under a floor where it does its damage quietly. If the gauge keeps sinking, stop feeding it and get the system traced properly.
One reset is a fair try — it clears plenty of one-off lockouts on its own. If the boiler locks straight back out, stop there. Repeated resets just batter a boiler that's already telling you something is wrong, and the fault code on the display helps a professional far more than a wiped history does.
In the UK, anyone working on gas appliances must be Gas Safe registered — it's the law, not a courtesy. When an engineer arrives for gas work, it's completely reasonable to ask to see the ID card. Oil-fired boilers, common across the countryside around Strabane, sit under their own separate technician registration — worth asking about that too.
A frozen condensate pipe is the usual culprit on a gas or oil condensing boiler — the small plastic pipe that drains acidic water away, often routed out through an external wall where the cold gets at it first. Once it freezes, the boiler locks out in protest. Thawing it gently with warm, never boiling, water and resetting once fixes many a frosty-morning breakdown without a call-out.
The main page — how the line works and the areas it covers.
Go to home →The first five minutes, in the right order.
Read the bulletin →What to try yourself and when it's NI Water's sewer, not yours.
Read the bulletin →Honest ballparks and the questions to ask before work starts.
Read the bulletin →Pressure, controls, the immersion — the checks before you call.
Read the bulletin →Thawing safely with gentle heat — and the lagging that prevents it.
Read the bulletin →Damp patches, falling pressure and the stopcock test.
Read the bulletin →Ring any hour to be put through to a local plumber covering Strabane and the surrounding towns and townlands — gauge reading and fault code in hand.
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