Commercial Boiler & Water Heater Fault Codes
Fault code lists for commercial boilers and water heaters — Ideal Evomax 2, Hamworthy, Remeha, Andrews, Lochinvar and Rinnai — plus guides to burner lockouts, gas valve, ignition and gas meter faults.
Every code list in this section is taken from the manufacturer's own manual or fault code tool, and each page links to its source. We do not publish code meanings we cannot confirm.
A fault code tells you where a commercial appliance's control has detected a problem, not always what caused it. Lockouts that return after a reset, gas valve faults and flame faults must be investigated by a Gas Safe registered engineer with the right commercial categories.
Guides in this section
- Ideal Evomax 2 Fault Codes (1–99) Explained
Full Ideal Evomax 2 fault code list from Ideal's user guide — thermistor, overheat, flame, fan, water flow and internal faults — with what each means.
- Hamworthy Fault Codes: Wessex ModuMax mk3/mk4, Upton, Stratton mk2, Varmax
Hamworthy fault codes for boilers with Siemens LMS controls — Wessex ModuMax mk3 and mk4, Purewell VariHeat mk2, Stratton mk2, Upton and Varmax — from Hamworthy's own list.
- Hamworthy Fault Codes: Purewell VariHeat, Fleet, Stratton mk1, Wessex ModuMax mk2
Hamworthy fault codes for boilers with Siemens LMU controls — Purewell VariHeat c and he, Fleet, Stratton mk1 and Wessex ModuMax mk2 and HE — from Hamworthy's list.
- Hamworthy Dorchester DR-FC Evo Water Heater Fault Codes
Hamworthy Dorchester DR-FC Evo direct-fired water heater fault codes and actions, from Hamworthy's fault code tool.
- Remeha Gas 210 Eco Pro Fault Codes (E:00–E:39)
Remeha Gas 210 Eco Pro fault codes from Remeha's installation manual, including E:14 (5 failed burner starts), E:12, E:15 and E:36.
- Remeha Quinta Pro Fault Codes (E00–E40)
Remeha Quinta Pro 30–115 error codes from Remeha's installation and service manual, including E14 burner start-up failures.
- Andrews MAXXflo Water Heater Fault Codes
Andrews MAXXflo commercial water heater fault codes — A lockout codes and E blocking codes — from Andrews' installation manual.
- Rinnai Infinity Water Heater Fault Codes (11, 12, LC)
Rinnai Infinity 26/32 and HD50/HD70 continuous flow water heater error codes from Rinnai UK's manual — 10, 11, 12, 14, 16, 32–34, 52, 61, 65, 71, 72 and LC.
- Lochinvar EcoSword Water Heater Fault Codes
Lochinvar EcoSword condensing water heater error codes from Lochinvar's manual — C, E, F and S codes, plus the Src and Ano warnings — and what each means.
- Commercial Burner Lockout: Causes and What To Do
Why commercial boilers and forced-draught gas burners go to lockout, the usual causes and when to call an engineer.
- Commercial Gas Valve Faults
Signs of a faulty gas valve on commercial boilers, burners and water heaters, and why valve faults must be handled by an engineer.
- Commercial Gas Boiler Ignition Faults
Why commercial gas boilers fail to ignite — no spark, spark but no flame, or flame lost — and how engineers find the cause.
- Commercial Gas Meter Faults: Who To Call
Common commercial gas meter and meter regulator faults — low pressure, creeping pressure, noisy or stuck meters — and who is responsible for each.