Potterton boiler fault codes
Promax Combi, System, and Store Error Codes
| Fault Codes | Possible Cause |
| E10 | Outdoor sensor error |
| E20 | Central heating thermistor sensor fault |
| E28 | Flue thermistor fault |
| E50 | Domestic hot water sensor fault |
| E110 | Boiler overheat tripped |
| E119 | System pressure too low |
| E125 | Primary water circulation fault |
| E130 | Flue thermostat sensor tripped (lockout) |
| E131 | Flue overheat lockout |
| E133 | Ignition fault. If you have a prepayment meter, please check the meter to ensure that the supply is ON because it might simply be that you have ran out of gas and need to top-up, then reset the boiler. |
| E151 | Printed circuit board (PCB) error |
| E152 | PCB error |
| E160 | Fan fault |
| E161 | Fan fault |
| E164 | Domestic hot water sensor error – could be a heating flow switch error) |
| E167 | Printed circuit board (PCB) fault |
| E168 | Printed circuit board (PCB) lockout |
| E193 | Circulation |
Potterton Promax Ultra, Gold/Titanium Combi & System Boiler Error Codes
| Fault Code | Possible Cause |
| E09 | Gas valve wiring fault |
| E10 | Outdoor sensor error |
| E15 | Gas valve connection fault |
| E20 | Central heating thermistor sensor fault |
| E28 | Flue thermistor fault |
| E40 | Central heating return thermistor fault |
| E50 | Domestic hot water sensor fault |
| E53 | Flue obstruction |
| E55 | Calibration required |
| E78 | Water pressure sensor fault |
| E83 / 84 / 85 / 86 / 87 | No communication between room controller and boiler |
| E92 | Combustion test alarm during auto-setting |
| E109 | Poor circulation |
| E110 | Boiler overheat tripped |
| E117 | System pressure too high (>2.9 bar) |
| E118 | System pressure too low |
| E125 | Primary water circulation fault |
| E128 | Loss of flame during operation |
| E129 | Loss of flame during calibration |
| E130 | Flue thermostat sensor tripped (lockout) |
| E133 | Ignition fault |
| E135 | Internal error |
| E154 | Primary flow fault |
| E160 | Fan fault |
| E270 | Dry fire |
| E317 | Wrong power supply (HZ) |
| E321 | Hot water thermistor fault |
| E384 | Flame detected when gas valve off (false flame) |
| E385 | Low voltage (less than 195v) |
Potterton Assure Combi and system Boiler Error Codes
| Fault Code | Possible Cause |
| E09 | Gas valve connection cable fault |
| E10 | External probe fault |
| E12 | Differential water flow switch is still open |
| E13 | Differential water flow switch is still closed |
| E15 | Fault with the gas valve command |
| E20 | Central heating negative temperature coefficient (NTC) fault |
| E28 | Flue negative temperature coefficient (NTC) fault |
| E40 | Central heating return negative temperature coefficient (NTC) fault |
| E50 | Domestic hot water (DHW) negative temperature coefficient (NTC) sensor (tank boiler) (s.c) or DHW NTC sensor (tank boiler) (o.c.) Fault |
| E83 / E84 / E85 / E86 / E87 | Communication error |
| E109 | Pre-circulation fault |
| E110 | Boiler Max temperature exceeded for gradient (or overtemperature) Probable pump jammed or air in the circuit or Safety thermostat sensor tripped |
| E118 | Primary system water pressure too low |
| E125 | Primary circulation fault |
| E128 | Flame failure (12 times) |
| E129 | Frequent loss of flame (safety error) |
| E130 | Flue thermostat sensor tripped and locked out |
| E133 | Possible gas supply issue (failure to light) |
| E134 | Elapsed time gas valve open without gas |
| E135 | Internal error (interruption of gas supply) |
| E154 | Flow/return sensor temperature test |
| E160 | Problem with fan (possible wiring fault) |
| E163 | Domestic hot water (DHW) negative temperature coefficient (NTC) sensor fault (s.c.) or DHW NTC sensor fault (o.c.) |
| E270 | Dry fire |
| E317 | Wrong power supply (HZ) |
| E321 | Hot water fault |
| E384 | False flame |
| E385 | Under voltage |
| E430 | Water pressure test |
| E430 + Flame crossed | Water pressure test failed |