Pressure basics, no-heat troubleshooting and the one situation where you shouldn't call a plumber at all — for homes in Coleraine and along the north coast.
Start at the pressure gauge: most combi boilers want roughly 1 to 1.5 bar when cold — your manual gives the exact range for your model. If the pressure looks right and you still have no heat or hot water, stop prodding and call a plumber. And if you can smell gas, skip this page entirely: leave the property and call 0800 111 999 from outside.
Leave the property now. Don't touch light switches, sockets or anything electrical on the way out, don't use naked flames, and don't stop to hunt for the leak.
Once you're safely outside, call the National Gas Emergency Number on 0800 111 999. A plumbing line is not the right contact for a suspected gas leak — call a plumber only after the gas emergency service has made things safe.
The gauge on the front of the boiler tells you more than any error code. Around 1 to 1.5 bar with the system cold is typical for most combis; check the manual for what your model actually wants. Well below that, and the boiler may just need a top-up through the filling loop — or it may be quietly losing water somewhere. Well above 2 bar, cutting out, or dumping water from the relief pipe outside? That's a call, not a DIY afternoon.
Around Coleraine that gauge earns its keep: some of the area's older properties still run aging boiler installations that were fine decades ago but are more prone to leaks, corrosion and pressure problems now.
Along the coast towards Portstewart, Portrush and Castlerock, salt-laden air and a good number of seasonal holiday lets add a twist: a boiler in a property left unheated for weeks over winter often reveals its faults only when someone next turns everything on. If that someone is you, work through the checks above calmly — gauge, controls, condensate pipe — before assuming the worst.
For most combi boilers, somewhere around 1 to 1.5 bar with the system cold is typical, though the right range for your model is in the manual — check it rather than guessing. Pressure rises a little as the system heats up, which is normal.
Often, yes. Most boilers have a filling loop for exactly this, and the manual for your model explains the steps. If you can't find the manual, aren't sure which valve is which, or the gauge shoots past 2 bar when you try, stop and ask a plumber to talk you through it instead.
A system that needs topping up again and again is losing water somewhere — a weeping radiator valve, a small leak in the pipework, or a fault inside the boiler itself. Repeated topping up hides the symptom without fixing the cause, so it's worth getting it investigated rather than living with the ritual.
When one half of the system works and the other doesn't, the fault often sits in the controls or the valve that switches the boiler between heating and hot water. Check the thermostat, timer and programmer settings first; if they're fine, it's a diagnosis job for a professional rather than something to dismantle yourself.
No. A suspected gas leak is an emergency, not a plumbing call. Leave the property, don't touch light switches or anything electrical, don't use naked flames, and call the National Gas Emergency Number on 0800 111 999 once you're safely outside. A plumbing line is not the right contact for gas.
Back to the Coleraine emergency plumber home page, or jump to another guide:
Stopcock first: the three steps that limit water damage fast.
Read the guide →What never to pour away, and when a blockage is a main-drain problem.
Read the guide →An honest look at call-out fees, hourly rates and out-of-hours pricing.
Read the guide →Pressure, thermostat, tripped switch or diverter valve — checks first.
Read the guide →Stopping pipes freezing in the first place, and thawing one safely.
Read the guide →Damp patches, dropping pressure, and the stopcock test that narrows it down.
Read the guide →The main page: what to do right now and the areas covered.
Go to home →This site connects callers with a local plumbing professional covering Coleraine, Castlerock, Garvagh and the surrounding area — day or night. No gas emergencies: for gas, call 0800 111 999.
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