A boiler breakdown is stressful — especially during a Northern Ireland winter. When you contact Kelly Heating NI, we'll ask you about your boiler make, model and any error codes displayed, and we'll do our best to help you as quickly as possible.
Where we can, we'll try to guide you through common minor issues over the phone — things like low pressure, a frozen condensate pipe, or incorrect thermostat settings — before arranging a callout. If the boiler needs an engineer, we'll get to you as fast as we can.
What to Do When Your Boiler Breaks Down
Check the error code
Look at your boiler's digital display. Note any error code shown — this helps us diagnose the problem faster. If there's no display, note the boiler make and model (usually on a label on the front).
Check your supplies
Check that other gas appliances (hob, fire) are working. If not, you may have a supply issue rather than a boiler fault. For oil boilers, check your oil level in the tank.
Check the pressure
Most modern combi boilers need a pressure of around 1–1.5 bar. If the gauge reads below 1, low pressure may be the issue — we can guide you through repressurising over the phone.
Call or WhatsApp us
Call 07934 776 774 or WhatsApp us with your boiler details. We'll advise you on next steps and arrange a visit as quickly as we can.
Common Boiler Faults We Repair
Our engineers have experience repairing all common gas and oil boiler faults across the main brands — Worcester Bosch, Vaillant, Ideal, Warmflow, Grant, Firebird and others.
- No heating or hot water
- Low boiler pressure
- Frozen condensate pipe (common in Northern Ireland winters)
- Pilot light or ignition failure
- Boiler lockout — error codes and fault resets
- Faulty diverter valve (hot water but no heating, or vice versa)
- Kettling — banging or rumbling sounds from the boiler or pipes
- Thermostat or controls failure
- PCB (printed circuit board) faults
- Pump failure
- Heat exchanger issues
- Oil boiler nozzle or burner faults
Oil Boiler Repair vs Gas Boiler Repair
Gas boiler repair: Must be carried out by a Gas Safe registered engineer. Kieran Kelly is Gas Safe registered, No. 557696. You should never attempt to work on a gas boiler yourself — this is both dangerous and illegal.
Oil boiler repair: Must be carried out by an OFTEC registered engineer. Kelly Heating NI is OFTEC certified and experienced with all major oil boiler brands used across Greater Belfast and Lisburn.
Repair or Replace? We'll Give You an Honest Answer
When we attend a breakdown, we'll diagnose the fault and give you a clear picture of your options before any work begins. If the repair is straightforward and cost-effective, we'll fix it. If the boiler is old, unreliable or the repair cost approaches replacement value, we'll tell you that honestly too.
We won't carry out expensive repairs on a boiler that's better replaced. And we won't push you toward a new boiler if a repair makes better sense. You'll get an honest assessment and the options — the decision is yours.
Find out more about our boiler installation service →
Preventing Future Breakdowns
The best way to avoid unexpected boiler breakdowns is an annual boiler service. A yearly service keeps your boiler running efficiently, extends its lifespan, and in most cases is required to keep the manufacturer's warranty valid.
Find out about our boiler servicing service →
Boiler Broken Down?
Call us now — we'll help as quickly as we can.
Frequently Asked Questions — Boiler Breakdown Belfast
Check the boiler display for an error code, check that other gas appliances are working, and check the boiler pressure gauge. Then call or WhatsApp us with your boiler make, model and any error code showing.
Yes. We repair both gas and oil boilers. Kieran Kelly is Gas Safe registered (No. 557696) for gas work and OFTEC certified for oil boiler repairs.
We are not a 24-hour service, but we will help you as quickly as we can. Call or WhatsApp us and we'll respond as promptly as possible.
The cost depends on what the fault is. We charge a callout/diagnostic fee and will give you a clear price for any repair before the work begins. There are no hidden charges.
Fault codes vary by manufacturer. Call or WhatsApp us with the code and your boiler make and model and we can often help you identify the issue before arranging a visit.
If your boiler is under 10 years old and the repair cost is reasonable relative to its value, repair is usually the right choice. If it's over 15 years old, repeatedly breaking down or the repair cost is high, replacement is often more cost-effective long-term. We'll give you an honest view.