Most boiler call-outs come down to low pressure, a misbehaving control, or a fault that genuinely needs an engineer. Check the pressure gauge first — around 1 to 1.5 bar when cold is typical for sealed systems — then the thermostat and timer, and if it's still dead, call 020 4577 2888. If you smell gas, skip all of this: leave the house and ring 0800 111 999 from outside.
Smell gas? Stop. Read this first.
A gas smell is not a boiler fault to troubleshoot — it's an emergency with its own rules. Leave the property now. Don't flick any switches on or off, don't use doorbells, don't light anything, and don't hunt for the source yourself.
Once you're outside and away from the building, call the National Gas Emergency Number on 0800 111 999 and do what they tell you. A plumbing line is not the right contact for gas. Come back to boiler repairs only after the gas emergency service has made the property safe.
Check the gauge
Find the pressure gauge on or near the boiler. On most sealed systems the needle should sit at roughly 1 to 1.5 bar when the heating is cold — your boiler's manual gives the exact figure for your model. A needle well below that range explains many "no heat" mornings: boilers simply lock out on low pressure. Most can be topped up through the filling loop, done slowly with the manual open. If the needle keeps sinking again days after a top-up, water is escaping somewhere — that's a job to have investigated, not a routine to live with.
Check 2Check the controls
Start with the boring things. Is the thermostat set higher than the room's actual temperature? Has the timer reset after a power cut? Is the display showing a fault code you can look up in the manual? From town-centre terraces in Omagh out to homes in Beragh, Sixmilecross and Newtownstewart, a surprising share of "broken boiler" calls turn out to be a control set wrongly or a code that points straight at the fix.
Check 3Sort heat from hot water
Notice exactly what's missing, because it narrows the fault: radiators cold but taps hot points one way, hot water gone but heating fine another, and both gone at once suggests the boiler itself. Radiators warm at the bottom but cold at the top usually just need bleeding with a radiator key. Tell whoever you call which combination you have — it saves diagnostic time you'd otherwise pay for.
When it's an engineer's job
Anything involving the sealed combustion side of the boiler, repeated lockouts, leaks from the casing, or a system that loses pressure over and over is beyond sensible DIY — and ageing boilers in older properties are more prone to leaks and pressure trouble than modern equivalents. Call 020 4577 2888, describe the symptoms and any fault code, and you'll be connected with a local professional. Be straightforward about where you are: distance from town affects arrival time in a rural district like this.