Potterton Boiler Fault & Error Codes
Boilers are like cars, a problem could occur when you least expect it for no apparent reason. 
The fault codes you will see are a letter and a number, they are designed to show up on your boiler display so you can go check on the Potterton website or the table below and see if it is a problem you can solve. If the fault code shows an error which you cannot solve, contact a Gas Safe registered engineer as soon as possible.
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Potterton Boiler Fault Code Table:
Potterton Assure Combi Boiler Fault Codes
| FAULT CODE | DESCRIPTION / POSSIBLE CAUSE |
| E09 | Gas valve connection cable. |
| E10 | External probe fault. |
| E12 | Differential water flow switch fault (still open). |
| E13 | Differential water flow switch fault (still closed). |
| E15 | Gas valve command fault. |
| E20 | Central heating NTC fault. |
| E28 | Flue NTC fault. |
| E40 | Central heating return NTC fault. |
| E50 | Domestic hot water (DHW) NTC sensor fault (tank boiler) (s.c.) or DHW NTC sensor fault (tank boiler) (o.c.). |
| E83, E84, E85, E86 or E87 | No communication. |
| E190 | Pre-circulation fault. |
| E110 | Boiler max temperature exceeded for gradient (could be a jammed pump or air in the circuit) or boiler maximum temperature exceeded for overtemperature (could be jammed pump or air in the circuit) or the safety thermostat has tripped. |
| E118 | Primary system water pressure is too low. |
| E125 | Circulation fault (primary). |
| E128 | Frequent flame failure – 12 times. |
| E129 | Safety error for frequent loss of flame with maximum correction during the ignition during calibration function. |
| E130 | Flue thermostat sensor has tripped (lockout). |
| E133 | Failure to light (could be an issue with gas supply). Check that the gas supply is available by lighting your gas fire or cooker. |
| E134 | Elapsed time gas valve open without gas (short request in a short period). |
| E135 | Interruption of gas supply (internal error). |
| E154 | Flow/return sensor temperature test. |
| E160 | Fault with fan or fan wiring. |
| E163 | Domestic hot water (DHW) NTC sensor fault (s.c.) or DHW NTC sensor fault (o.c.). |
| E270 | Circulation fault (dry fire). |
| E317 | Wrong power supply electrical frequency (Hz). |
| E321 | Hot water NTC fault. |
| E384 | False flame. |
| E385 | Under voltage. |
| E430 | Water pressure temporary test. |
| E430 + flame crossed | Water pressure test failed. |
Potterton Promax Ultra Boiler Fault Codes
| FAULT CODE | DESCRIPTION / 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, E84, E85, E86 or E87 | No communication between boiler and room controller. |
| E92 | Combustion test alarm during auto-setting. |
| E109 | Poor circulation. |
| E110 | Boiler overheat has tripped. |
| E117 | System pressure too high. |
| 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 has tripped (lockout). |
| E133 | Ignition fault. |
| E135 | Internal error. |
| E154 | Primary flow fault. |
| E160 | Fault with fan. |
| 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 Promax Combi, System and Store Boiler Fault Codes
| FAULT CODE | DESCRIPTION / 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 has tripped. |
| E119 | System pressure too low. |
| E125 | Primary water circulation fault. |
| E130 | Flue thermistor sensor has tripped (lockout). |
| E131 | Flue overheat lockout. |
| E133 | Ignition fault. |
| E151 or E152 | PCB error. |
| E160 or E161 | Fault with fan. |
| E164 | Domestic hot water sensor error (UK) or heating flow switch error (ROI). |
| E167 | PCB fault. |
| E168 | PCB lockout. |
| E193 | Circulation error. |
Potterton Gold Combi, Gold System and Titanium Combi Boiler Fault Codes
| FAULT CODE | DESCRIPTION / 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, E84, E85, E86 or E87 | No communication between boiler and room controller. |
| E92 | Combustion test alarm during auto-setting. |
| E109 | Poor circulation. |
| E110 | Boiler overheat has tripped. |
| E117 | System pressure too high. |
| 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 has tripped (lockout). |
| E133 | Ignition fault. |
| E135 | Internal error. |
| E154 | Primary flow fault. |
| E160 | Fault with fan. |
| 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. |