Electrical & controls
Relays, contactors, control signals, interlocks and plant sequencing.
DIAGNOSTICS & REPAIRS
Specialist diagnostics across complex HVAC plant.
Methodical fault investigation across VRV/VRF, chillers, refrigeration, ventilation, heating plant, pumps and associated electrical controls.
Diagnosis before unnecessary replacement
A fault code is a starting point, not always the root cause. We trace faults across power supplies, communication networks, control logic, refrigerant circuits, airflow and water-side performance to understand why equipment is failing.
Depending on the system, investigations may involve electrical control circuits, communication wiring, refrigerant circuits, mechanical components, flow and temperature checks.
Refrigeration circuits
Leak investigations, pressure and temperature checks, compressors and heat exchangers.
Water-side performance
Pumps, valves, flow conditions, pressurisation and heat transfer.
Mechanical repairs
Motors, fans, drive components and related plant equipment.
FAULT INVESTIGATION
Methodical diagnostics. Clear next steps.
Our work is centred on proving the fault and identifying an appropriate repair rather than replacing parts by guesswork.
Establish the operating conditions
Confirm symptoms, equipment history, fault codes and the conditions under which the issue occurs.
Test the relevant systems
Assess power and control circuits, interlocks, airflow, water-side conditions and refrigerant performance as appropriate.
Identify the root cause
Separate a failed component from upstream controls, site conditions or another system creating the same symptom.
Explain the findings
Provide a practical summary of what was checked, what was found and what is recommended.
Plan the repair
Advise on replacement parts, further investigation or remedial works where needed.
Verify operation
Where work is completed, carry out appropriate operational checks and highlight any remaining limitations.
SPECIALIST INVESTIGATION
Controls, communications and mechanical faults.
Some failures sit at the boundary between disciplines. QMES investigates HVAC equipment and associated controls together, helping avoid repeated visits and unnecessary component changes.
View diagnostics photography ↗NEXT STEPS
Need help with a system fault?
London, the Home Counties and East Anglia · Commercial and domestic enquiries welcome.