In this article, you’ll find the five most common fault codes for the Rendamax R600 EVO commercial boiler, what each code means and the steps required to resolve the issue.
Please note that any work carried out on a commercial boiler must only be undertaken by a qualified Gas Safe registered engineer. If you require an experienced engineer who specialises in Rendamax boilers, please contact us to arrange a site visit. Our team is also available to provide technical support and advice whenever you need assistance.
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Common Rendamax R600 EVO Fault Codes & What they Mean
| Fault Code | Definition | Quick Checks | Causes | Solutions |
| 78 | Water Pressure Sensor Fault | Reset boiler, Check system pressure on gauge, re-pressurise system if low, Inspect pressure sensor wiring/connector, Check for moisture or corrosion on sensor plug | Faulty water pressure sensor, Loose or damaged wiring/connector, Low system water pressure, Air in system affecting readings, PCB input fault | Top up system pressure, Reconnect or repair wiring, Replace faulty pressure sensor, Bleed air from system, Replace PCB if sensor input circuit defective |
| 110 | Flow Temperature Sensor Fault | Reset boiler, Check system pressure and circulation, Inspect flow sensor connection/plug, Check wiring for damage/corrosion, Ensure sensor is firmly fitted in position | Faulty flow temp sensor, Loose or damaged wiring connector, Corroded or wet sensor plug, Poor circulation causing abnormal readings, PCB sensor input fault | Reconnect or repair wiring, Replace faulty flow temp sensor, Restore proper system circulation, Replace PCB if sensor input is faulty |
| 166 | Air Pressure Switch Does Not Open | Reset boiler, Check fan stops properly after shutdown, Inspect air pressure switch tubing, Check flue & air intake for obstruction, Inspect condensate trap/drain for blockage, Check wiring to fan & pressure switch | Stuck or faulty air pressure switch, Water/condensate in pressure tubes, Fan not stopping correctly, Blocked flue or air intake, Wiring/connector fault, PCB fan control issue | Clear/replace pressure tubes, Repair wiring/connector issues, Replace faulty air pressure switch, Clear flue/condensate restrictions, Replace fan or PCB if control fault persists |
| 388 | DHW Sensor/Input Configuration Fault | Reset boiler, Check DHW sensor is connected properly, Inspect sensor for damage or corrosion, Verify sensor is correctly positioned in cylinder/pocket, Check control settings for DHW function enabled | Faulty DHW sensor, Loose or disconnected wiring, Incorrect parameter or input configuration, Corroded or wet connector, PCB input fault | Reconnect or repair wiring, Replace faulty DHW sensor, Correct controller configuration settings, Replace PCB if sensor input circuit is faulty |
| 132 | Gas Pressure/Gas Safety Circuit Fault | Reset boiler, Check gas supply is on, Confirm other gas appliances work, Check boiler gas isolation valve is open, Inspect gas pressure switch wiring/connector, Check condensate & air intake are clear | Low or no gas supply pressure, Gas isolation valve closed or partially closed, Faulty gas pressure switch, Loose/damaged wiring to safety circuit, Gas valve not operating correctly, External gas supply issue | Restore gas supply and open valves fully, Repair wiring/connector issues, Replace faulty gas pressure switch, Gas pressure test and adjustment by engineer, Replace gas valve is not operating correctly |
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