In short
Commercial heating failures are not always caused by the boiler. Heat can be lost through failed circulation pumps, stuck valves or actuators, control and schedule faults, pressure problems or airlocks in the distribution system. Note which areas are cold, whether the boilers are running and any alarms, then contact a commercial heating engineer to diagnose the system as a whole.
Is it urgent?
Call now if
- Heating has failed across the building in cold weather
- Vulnerable occupants, care, healthcare or education spaces are affected
- There is a water leak from heating pipework, valves or emitters
- Frost protection has failed and pipework could freeze
Usually suitable for scheduled work
- A single room or zone is cooler than the rest of the building
- Radiators need balancing or individual valves are sticking
- Comfort complaints with no loss of heating plant
Loss of heating in commercial properties
Commercial heating systems are networks: boilers or heat pumps produce heat, pumps circulate it, valves and controls direct it, and radiators, fan coils, air handling units or underfloor circuits deliver it. A failure anywhere in that chain can leave part or all of a building cold.
Building-wide or localised failure?
| Pattern | Where to look first |
|---|---|
| Whole building cold, boilers off or locked out | Boiler fault, pressure, gas supply, interlocks |
| Whole building cold, boilers running | Circulation pumps, main valves, airlocks, controls |
| One zone, floor or wing cold | Zone valve, actuator, secondary pump, mixing circuit, schedule |
| Individual rooms cold | Radiator or fan coil valve, thermostatic head, airlock, local controller |
| Heating only fails at certain times | Time schedules, optimiser settings, frost protection logic |
Failed circulation systems and heating pumps
When a circulation pump fails or trips, heat stays in the plant room. Boilers may then overheat and lock out, making the boiler look like the cause. Duty and standby pumps should change over automatically, but changeover can fail. See commercial pump repairs.
Valves and distribution equipment
Motorised valves, actuators and mixing valves can stick in one position. Isolation valves left closed after maintenance are a frequent, simple cause. Airlocks in high points stop circulation through parts of the system.
Boiler and heating control faults
BMS schedules, setpoints, optimisers and weather compensation decide when and how hard the plant runs. A changed setting, failed outside air sensor or lost communication can stop the heating starting. See BMS and controls faults.
Assessing affected areas
Before calling, note:
- which floors, zones or rooms are cold, and which are warm
- whether the boilers are firing and the pumps are running (if visible without entering unsafe areas)
- the system pressure gauge reading
- any BMS alarms or fault codes
- when the problem started and anything that changed, such as recent maintenance
Safe fault reporting
Do not open electrical panels, bleed high-level pipework or adjust pressurised equipment unless you are trained and authorised. Hot water at system pressure can cause serious scalds.
Professional diagnosis
An engineer will check flow and return temperatures across the plant and circuits, pump operation, valve positions, system pressure and control signals to find where heat is being lost, then repair the fault or make the system safe.
Maintenance follow-up
After an emergency, review whether planned maintenance covered pumps, valves, pressurisation and controls. Recurring heating failures often trace back to items that are not on the schedule. See emergency preparation.
Commercial Heating Repairs: frequently asked questions
What causes commercial heating systems to stop working?
Common causes are boiler lockouts, failed circulation pumps, low system pressure from a pressurisation unit fault or leak, valves or actuators stuck closed, BMS schedules or setpoints not calling for heat, airlocks, and failed sensors. Heating loss in one area usually points to distribution or controls rather than the boilers.
The boilers are running but the building is cold. Why?
If the boilers are firing but heat is not reaching the building, the problem is usually circulation (a failed or tripped pump, closed valve or airlock), controls (a valve not opening or a zone not enabled) or a mixing circuit fault. A heating engineer will check flow and return temperatures to find where heat is being lost.
Is there a legal minimum temperature for workplaces?
HSE guidance says workplace temperatures should normally be at least 16°C, or 13°C where work involves rigorous physical effort. When heating fails, employers should assess the risk and consider temporary measures.
Can portable heaters be used while heating is repaired?
Temporary heating can help, but it must be suitable for the space, electrically safe and not create fire or trip hazards or overload circuits. Check with your facilities and health and safety teams before deploying it.
How is a heating repair different from a boiler repair?
A boiler repair focuses on the appliance itself. A heating repair looks at the whole system that delivers heat, including pumps, valves, pipework, emitters, pressurisation and controls. See commercial boiler repairs if the boiler is the problem.
UK guidance and references
Primary and industry sources relevant to this subject. Always check the current edition and how it applies to your building.
- Workplace temperatures Health and Safety Executive
- Workplace (Health, Safety and Welfare) Regulations 1992 legislation.gov.uk
- Gas safety Health and Safety Executive