In short
Commercial HVAC repairs start with diagnosing why a system has stopped, is underperforming or is showing an alarm. An engineer checks power, controls, airflow, water flow and refrigerant circuits to find the cause, makes the system safe, and then repairs or replaces the failed components, testing the system before it is returned to service.
What HVAC repairs involve
Repairs follow a structured approach so the real cause is fixed, not just the symptom:
- Make safe. Isolate equipment where needed and check for immediate hazards such as water leaks onto electrics or refrigerant leaks in enclosed spaces.
- Diagnose. Check supplies, controls and alarms, then airflow, water flow and refrigerant pressures and temperatures.
- Repair. Replace or repair failed components, clear blockages and correct settings.
- Test. Run the system, confirm it is working to its intended performance, and record readings.
- Report. Explain the cause and anything that could prevent a repeat.
When you need a repair
- air conditioning is running but not cooling, or heating is not reaching temperature
- a unit is leaking water from the ceiling or casing
- fans are noisy, vibrating or not running
- the BMS or controller shows a fault code or alarm
- ventilation feels stuffy or rooms smell stale
- energy use has jumped without explanation
Our HVAC breakdown guide explains what you can safely check before calling.
Equipment we repair
| Equipment | Common repairs |
|---|---|
| Air conditioning (VRF/VRV, split, cassette) | Leaks, PCB and sensor faults, fans, condensate pumps |
| Air handling units | Fan motors, belts, bearings, dampers, actuators, frost stats |
| Fan coil units | Valves and actuators, fans, condensate pumps, controllers |
| Chillers | Alarms, sensors, flow faults, compressor and fan issues |
| Heat pumps | Defrost, sensor and flow faults, refrigerant issues |
| Ventilation | Fan motors, belts, controls, speed controllers |
| Controls | Sensors, thermostats, time schedules, BMS points |
Our process
- Report the fault by phone or the form below, with as much detail as you have.
- We agree attendance with you; timing depends on location, engineer availability and site access.
- The engineer diagnoses the fault and makes the system safe.
- Simple repairs can often be completed on the first visit; where parts are needed, we confirm the remedy and cost.
- You receive a written record of the fault, the work done and any recommendations.
Typical applications
Offices with overheating meeting rooms, hotels with guest-room comfort complaints, retail units with failed cassettes, server rooms with cooling alarms, and warehouses with ventilation faults.
Maintenance considerations
Many repairs trace back to missed routine tasks: dirty filters, blocked condensate drains and slack belts. If the same fault keeps returning, a planned maintenance schedule is usually cheaper than repeated call-outs.
Compliance and safety
Do not open panels on live equipment. Inside HVAC units there are live electrical parts, rotating fans and pressurised refrigerant. Leave diagnosis to competent engineers.
Repairs to refrigerant circuits must be carried out by F-gas certified engineers, and leaks must be repaired and re-checked as the regulations require. Electrical work must follow safe isolation procedures.
Coverage across London
We take repair enquiries for commercial premises across London and Greater London. See areas we cover.
HVAC Repairs: frequently asked questions
What information should I give when reporting a fault?
Tell us the site address and postcode, the equipment affected, what it is doing (or not doing), any fault codes or alarms on the controller or BMS, when it started, and how access works on site. Photos of the unit, its rating plate and any error display help us arrive prepared.
Can you repair a system you did not install?
Yes. We diagnose and repair commercial HVAC equipment regardless of who installed it. For some older equipment, parts availability can limit repair options, and we will tell you if that is the case.
What are the most common commercial HVAC faults?
Common causes include blocked filters and coils, failed fans or capacitors, blocked condensate drains, faulty sensors and actuators, controls set incorrectly, low refrigerant charge caused by leaks, and tripped electrical protection.
Is it safe to keep resetting a unit that keeps tripping?
No. Repeated tripping usually indicates an electrical, mechanical or refrigerant problem. Repeated resets can make damage worse. Leave the unit off and arrange for an engineer to investigate.
Do you give a price before carrying out repairs?
Where the repair goes beyond the diagnostic visit, we explain the fault and the recommended remedy and confirm the cost before proceeding, unless you have agreed different arrangements in a maintenance contract.
What if the fault is urgent?
For urgent faults, such as loss of cooling to a server room or a complete ventilation failure, call our 24/7 contact line on 020 7998 9005. See emergency HVAC support.
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
- Electrical safety at work Health and Safety Executive
- F gas in refrigeration and air conditioning GOV.UK