Commercial boilers are made with high-quality components, are designed to be reliable, and are built to last a long time. However, commercial boilers and heating systems are complex and can occasionally go wrong, especially with older boilers that are used every day. Here are some common issues and their likely causes.
Leaks
Leaks can have several causes including corroded pipes, faulty valves or a faulty heat exchanger. If water is lost in the heating system, it causes energy inefficiency and could damage the system or cause an electrical short circuit. Ignoring a leak could lead to expensive repairs.
If a leak is spotted, it is important that it is checked by a heating engineer who can identify the cause and repair it.
Low pressure
The main causes of low boiler pressure are water loss, trapped air or a faulty pressure relief valve.
Boilers usually have a pressure gauge. If the gauge goes below one bar, the boiler will probably shut down. A qualified engineer can fix the problem and repressurize the system.
Strange noises
Banging, whistling or gurgling noises indicate that something is wrong. This could be caused by a malfunctioning pump, air in the system or kettling (localized boiling) from a build-up of limescale or sediment in the heat exchanger.
Humming or whining is a sign of worn pump bearings, a defective burner or a faulty fan.
If there are loose components a vibrating or rattling sound may be heard.
Grinding noises indicate that one or more components are failing.
A modern commercial boiler should operate at low noise levels. If any unusual sounds are heard, call in a heating engineer.
Cold or low temperature water
If the boiler is switched on, but there is no heat or hot water, this can be due to several causes, including a faulty thermostat, malfunctioning diverter valve or ignition issues.
Before calling out an engineer, check that the thermostat is set to the correct temperature and make sure that the boiler controls are at the right settings. Read the boiler user manual troubleshooting section to see if there is a quick fix. If none of these steps solves the problem, call out an engineer.
If the water in the system is warm but not hot enough the thermostat could be faulty, burners may be dirty and there may be a clogged air filter or a fault with the boiler ignition system. A heating engineer can fix these issues.
The boiler does not switch on
If the boiler does not switch on and there is no power indicator light, this is probably a power supply issue. Check the mains power supply and fuses.
If the boiler is fuelled by gas, it will not switch on if there is no gas supply. If this happens call the Gas Emergency Services at 0800 111 999.
The pilot light won’t stay lit
If the pilot light keeps going out or fails to light, there are several causes. There could be a dirty or damaged thermocouple, a dirty pilot orifice, a blocked pilot light jet or a faulty gas regulator.
If the pilot light goes out when it is windy, check for strong drafts. If there is one, weatherproof the area where the boiler is located.
If there is a fault in the electricity supply it will affect the ignition system that lights the pilot light.
If the pilot light continues to go out, don’t attempt to fix it yourself, call a heating engineer.
Uneven heat distribution
If some areas of the building are warm enough, but others cold, this could stem from a faulty thermostat, blocked air filters, leaks, clogged burners or low water pressure. In freezing weather, check for frozen condensation on pipes.
If there is a smart thermostat that heats different zones, check that it is set correctly before calling a heating engineer to fix the issue.
All commercial boilers have many components that could go wrong. The boiler must be serviced at least once a year. Call Xgas to arrange a service where the engineer will check that the boiler is working well and replace any faulty or worn parts. If the boiler does develop a fault or stops working, an Xgas engineer will happily fix the problem.