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Main Boiler Error Codes

Error codes are shown on Main boilers to indicate that the product has an issue. Below you will find a list of Main boiler error codes for all current Main products and we’ve even given you guidance (where available) on the action you need to take.

Error CodePossible Fault
E09Gas valve connection error
E15vGas valve error
E20Central heating negative thermistor coefficient (NTC) sensor error
E28Flue negative thermistor coefficient (NTC) sensor error
E40Central heating return sensor error
E83Communication error
E109Pre-circulation fault
E110Safety thermostat operated
E118Primary system water pressure too low
E125Circulation error
E128Flame error
E130Flue negative thermistor coefficient (NTC) sensor operated
E133Interruption of gas supply or flame error
E135Interruption of gas supply
E154Flow return sensor temperature test
E160Fan or fan wiring error
E270Circulation fault (dry fire)
E321Hot water negative thermistor coefficient (NTC) error
E384False flame
Error CodePossible Fault
E09Gas valve connection error
E15vGas valve error
E20Central heating negative thermistor coefficient (NTC) sensor error
E28Flue negative thermistor coefficient (NTC) sensor error
E40Central heating return sensor error
E83Communication error
E109Pre-circulation fault
E110Safety thermostat operated
E118Primary system water pressure too low
E125Circulation error
E128Flame error
E130Flue negative thermistor coefficient (NTC) sensor operated
E133Interruption of gas supply or flame error
E135Interruption of gas supply
E154Flow return sensor temperature test
E160Fan or fan wiring error
E270Circulation fault (dry fire)
E321Hot water negative thermistor coefficient (NTC) error
E384False flame
The error code E133 on the Main boiler simply means that the condensate pipe is frozen. This issue usually occurs during the cold winter months as the condensate pipe leads outside. Luckily this is an issue that can be resolved fairly quickly without the need for an engineer. You just need to thaw out the condensate pipe.
Error CodePossible Fault
1 Green FlashBoiler temp reached
2 Green FlashBoiler temp reached
3 Green FlashTemporary Flame Loss
4 Green FlashCommunication error between PCB and Control
5 Green FlashParameter Error On PSU/PCB
6 Green FlashMiscellaneous Error
1 Red FlashSensor Error; Sensor Fault, Temperature Fault or Flow Fault
2 Red FlashBoiler overheat tripped
3 Red FlashIgnition fault. Boiler has attempted to light 5 times and failed
4 Red FlashFan Fault
5 Red FlashParameter or PSU Error
6 Red FlashMiscellaneous

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