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Cold radiators, a flashing code, a gauge that won't sit still — let's work through it together, one check at a time.
My boiler's stopped working — what do I actually do? Check the gauge first: if the pressure sits below about 1 bar, top it up once through the filling loop using your boiler's manual. Note any error code on the display, try one reset, and if it won't come back — or the same fault returns — ring 020 4577 2888 and I'll put you through to a local plumber. If you smell gas, skip all of this: leave the house and call 0800 111 999.
Because the water in your sealed heating system is escaping somewhere. Once is life; repeatedly is a leak that wants finding.
Here's what I'd check with you first. The gauge on the front of most sealed-system boilers should sit around 1 to 1.5 bar when the heating's cold — your manual gives the exact happy zone 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 to do yourself, and doing it once or twice a year after bleeding radiators is nothing I'd worry about.
What earns my suspicion is the pattern. If you topped up last week and the needle's already sagging again, the system's losing water somewhere — a weeping radiator valve, a joint under the floor, a pinhole you'll never spot from outside. Every top-up adds fresh water and fresh oxygen to the system, quietly feeding corrosion while the leak feeds itself. That's the point I'd want to stop treating the symptom and trace the actual cause. If your gauge sits high instead, well past 2.5 to 3 bar, or climbs after you bleed radiators, I'd suspect a filling loop that wasn't closed fully or a failing expansion vessel — mention the number when you ring.
Pressure, then thermostat and timer, then a tripped switch. Three checks, two minutes, before you assume the worst.
I'd start where I always start: the pressure gauge, because low pressure alone can silence a boiler completely. If that's fine, check the room thermostat is actually calling for heat and the programmer hasn't quietly slipped its schedule — an accidental knock or a recent power cut can reset a timer without anyone noticing. Next, the fused spur or switch near the boiler, and the trip switches at your consumer unit; a tripped RCD can take the boiler down with everything else on that circuit.
If all three check out and you're still standing in a cold house, that's genuinely the point to stop guessing and let me take a look. I'd rather you ring after two minutes of sensible checks than spend an evening cycling the reset button on a fault that reset can't fix.
It's the boiler's own shorthand for what hurt, and it means different things on different makes. 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's long gone. Codes broadly sort into themes: pressure and circulation, ignition and flame detection, fans and sensors, condensate drainage.
Two habits serve you well here, and I'd walk anyone through them the same way. First, record the code before touching anything — photograph the display, since a reset can wipe the very clue I need. Second, resist the urge to reset over and over; one attempt is diagnosis, five is punishment, and a boiler that keeps locking out on an ignition or flame fault is asking for a professional, not persistence. Anything about flame, combustion or gas supply is strictly look-don't-touch territory.
Leave the property, don't touch switches or flames, and call the National Gas Emergency Service on 0800 111 999 once safely outside. Not me, not any plumber — that number, first.
A gas smell is the one situation on this page where I want you to stop reading and act. 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 they run 24 hours a day.
Once the property's been made safe, then and only then does a plumber or heating engineer come into it for any repair work. Anyone working on gas appliances in the UK must be Gas Safe registered by law, so asking to see the card is normal, not rude. I'm the right call for boilers, leaks and pipework — for a suspected gas escape I'm emphatically the wrong first call, and I'd rather tell you that plainly than ever be rung first in that situation.
Once or twice a year, after bleeding radiators, that's perfectly normal and I wouldn't worry about it. What I'd want you to notice is a pattern — topping up every week or two means the system is losing water somewhere, and covering that up with the filling loop just delays finding the actual leak.
In the UK, anyone working on gas appliances must be Gas Safe registered — that's the law, not a nice-to-have. When any engineer arrives for gas work, it's completely reasonable to ask whether they're Gas Safe registered and to see the ID card. Oil-fired boilers, common on rural properties around Armagh, have their own separate technician registrations — ask about those too.
A frozen condensate pipe is the classic culprit — the little plastic pipe that drains acidic water from a condensing boiler, often out through an external wall. When it freezes, the boiler shuts itself down as a safety measure. Thawing that pipe gently with warm, never boiling, water poured along it, then resetting the boiler, fixes many a cold-snap breakdown without a call-out.
Leave the property, don't touch switches or flames, and call the National Gas Emergency Service on 0800 111 999 once safely outside. Not a plumber, not me — that number, first, every single time. Only go back inside once you've been told it's safe.
The main page — how the line works and the areas it covers.
Go to home →The first five minutes, in the right order.
Walk through it →What to try yourself and when it's the sewer, not your drain.
Walk through it →Honest ballparks and the questions to ask before work starts.
Walk through it →Pressure, controls, the immersion — the checks before you call.
Walk through it →Thawing safely with gentle heat — and the lagging that prevents it.
Walk through it →Damp patches, dropping pressure and the stopcock test.
Walk through it →Ring any hour and I'll put you through to a local plumber covering Armagh and the surrounding villages.
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