When a commercial boiler pilot light keeps going out, you lose heat in an occupied building, and you may have a fault in a safety system. This guide sets out what a facility manager can check, record and arrange safely, and what must be left to a Gas Safe registered engineer. By the end you will have a clear fault log, a prepared brief for the engineer and a plan to stop the problem returning.
Before you start, have access to the plant room, the boiler's make and model, and your service and maintenance records to hand.
Start with your senses. Is there a smell of gas, a hissing sound near pipework, or a carbon monoxide (CO) alarm sounding or showing a warning? If any of these are present, do not investigate further.
If there is no sign of a leak, treat the problem seriously anyway. A pilot that repeatedly goes out is usually a symptom, not a nuisance. Most boilers have a flame supervision device, which shuts off the gas when it cannot prove that a flame is present. It is doing its job. Relighting again and again, or asking someone to bypass or defeat the device, removes the protection that stops unburnt gas building up.
Only a Gas Safe registered engineer may open, adjust, clean, repair or replace gas components, flues and safety devices on a boiler. You can check any engineer or business on the Gas Safe Register.
The legal background is straightforward. Under the Health and Safety at Work Act 1974, employers must, so far as reasonably practicable, protect the health and safety of employees and others affected by their work activities. The Gas Safety (Installation and Use) Regulations 1998 place duties on employers and landlords to keep gas appliances, fittings and flues in safe condition. Exactly which duties apply depends on your premises and tenancy arrangements, so confirm your own position if you are unsure.
Some causes sit outside the boiler, and you can check them from a safe distance without opening anything.
Find out whether other gas appliances are working, such as kitchen equipment or other boilers on site. If none are, the problem may be the supply. Check for a prepayment meter that has run out of credit, and ask whether the network or your supplier has carried out recent works nearby. If a supply interruption is confirmed, the boiler may simply have lost gas, but an engineer should still check it before it is restarted after a supply restoration.
Look at the room itself. Are ventilation grilles blocked by stock, pallets or paint? Is anything stored against the boiler or flue? Is an external door, louvre or vent open? North East winter winds, particularly on exposed coastal and Tyneside sites, can cause strong draughts through a plant room, and poor air supply can upset combustion. Clear obstructions that are not part of the boiler or its pipework, and close doors that should be shut.
Check that the boiler has power and that the isolator is on. If the display shows a lockout or fault code, write it down exactly as shown, including any letters, numbers and flashing patterns. A lockout is a safety state in which the boiler stops and will not restart until it is reset.
Reset only if the manufacturer's instructions explicitly allow users to do so, and follow them exactly. If the boiler locks out again after one or two resets, stop. Repeated resets are a sign that something is wrong, and continuing to press the button does not fix it.
An engineer can diagnose faster when they know when and how the problem happens. Start a log today and keep it beside the plant room door or in your facilities system.
Record each failure, and note things you can see without removing any covers:
Patterns matter because different causes show up in different ways. A fault that happens at start-up each morning points in a different direction from one that appears only in high winds, when a door slams, or at peak demand when other plant is running. Intermittent faults that follow the weather may suggest air supply or flue issues, while those linked to heating demand may suggest gas supply or valve concerns. You are not diagnosing, just giving the engineer evidence.
A simple format works well. Use one row per event with these columns:
Include who made each entry so the record stands up if it is needed later.
Knowing the terms helps you follow the engineer's explanation and ask good questions.
These are the usual areas an engineer will investigate. They are not jobs for anyone else:
Whether your boiler has a standing pilot at all depends on the model. Older atmospheric boilers are more likely to have one, while many modern units use electronic ignition and light the burner only when needed. Check the manufacturer's documentation or ask the engineer which system you have.
Three misconceptions are worth dispelling. First, relighting a pilot repeatedly is not harmless: each failure means the safety system could not prove a flame. Second, it is not always just a draught, and assuming so can mask a flue or combustion fault. Third, a thermocouple or flame supervision device must never be bypassed. Doing so is dangerous and may breach the Gas Safety (Installation and Use) Regulations 1998.
Check the engineer's credentials before they arrive. Search the Gas Safe Register for the business or the engineer's licence number, and confirm that their registration covers commercial gas work, as the categories differ from domestic. On the day, ask to see their Gas Safe ID card and check it against the register.
Gather this information so diagnosis is quicker:
Decide whether this needs an emergency callout. Request one if the building is occupied and has no heating, if vulnerable people are affected, if the boiler is locking out repeatedly, or if there is any gas smell or CO alarm. In the last two cases, remember that a gas smell or alarm means calling 0800 111 999 first. Commercial Boiler Solutions offers emergency callouts and same-day service for commercial properties across the North East and Northumberland.
Finally, arrange safe access. Make sure the plant room is unlocked and clear, let the engineer know about any site induction or permit requirements, and tell occupants that short interruptions to heating or hot water are possible during testing.
The scope of work depends on what the engineer finds, but you can usually expect checks of the combustion and safety devices, a gas tightness test, and a flue inspection. Where a part has failed, such as a thermocouple, flame sensor or valve, it will be replaced by the engineer. Do not expect to be asked to approve work you do not understand: ask for it to be explained in plain terms.
If the faults are recurring, you may face a repair or replace decision. Ask the engineer:
Costs will vary with the boiler and the fault, so get them in writing before work goes ahead rather than relying on estimates from articles like this one.
Before the engineer leaves, ask for a written report or service record that sets out what was found, what was done, and any warnings or recommendations. Keep it with your plant records, as it may be needed for audit or insurance.
Also ask directly: is the boiler safe to run? An engineer may leave it in service, or turn it off and label it as unsafe if there is a risk. If it has been disabled, find out what must happen before it can be recommissioned, and do not restart it yourself. Under the Gas Safety (Installation and Use) Regulations 1998, an unsafe appliance should not be used until it has been made safe.
Sensors, pilot assemblies and valves wear over time, and a service finds that wear before it causes a lockout on a cold morning. Book your annual service and inspection before the heating season, ideally in early autumn, so any parts needed can be fitted before demand peaks. If you are reading this in late October and have not had one this year, it is still worth arranging now: our commercial boiler maintenance and annual inspection service is designed for exactly that.
Alongside servicing, a few habits help:
If you manage several sites across Newcastle, Sunderland, Middlesbrough and Teesside, a maintenance contract can bring servicing, records and response times under one arrangement. See our maintenance contract options and our FAQ page for more detail.
Consider CO alarms where appropriate, and test them according to the manufacturer's instructions. Requirements depend on the premises and its use, so check current HSE guidance and your own risk assessment rather than assuming one rule fits every building. An alarm is a backup, not a substitute for servicing.
Once the fault is diagnosed and the boiler is confirmed safe, keep your log and the engineer's report together. They will make the next visit quicker and show that you have acted responsibly if questions arise.
If your boiler is still failing, or you would like to prevent it, Commercial Boiler Solutions is Gas Safe registered, holds a 5-star customer rating and serves commercial properties across the North East and Northumberland, including Tyneside, Wearside, Teesside and North Yorkshire. We can help with same-day assistance, emergency callouts or a maintenance contract. Learn more about our services.