Grant Combi Boiler Error Codes When there are problems with your boiler, it can be a frustrating time. So, in this guide, we provide the information you need to work out what the problem may be. If your home is installed with a Grant boiler, we’ll be taking you through some of the most common problems you might come across and how to get the boiler going again. Should you be in any doubt at all about what’s wrong with your boiler, use our free service to get quotes from reliable engineers near you.
Grant Boiler Error Code Solutions
| Grant Boiler Error Codes | |
| Fault Code | Cause of Problem |
| No display | 12V transformer failure |
| PP1 | Inlet (return) water temperature sensor failure |
| PP1 | Inlet (return) water temperature sensor failure |
| PP2 | Discharge gas sensor failure |
| PP3 | Coil temperature sensor failure |
| PP4 | Return gas sensor failure |
| PP5 | Ambient temperature sensor failure |
| PP6 | Discharge gas overheat protection |
| PP7 | Winter anti-freeze protection in operation |
| EE1 | High pressure – circulating pump failure or circuit air locked |
| EE2 | Low pressure |
| EE3 | Open circuit between PCB terminals 23-24 |
| EE4 | Supply L and N are reversed |
| EE8 | Communication failure |
| Flashing on and off | Defrosting |
| E01 | Internal control fault |
| sHr | HP flow sensor short / HP return sensor short |
| OPn | HP flow sensor open / HP return sensor open |
| SUP | Supply sensor short / Supply sensor open |
| OUTDR | Outdoor sensor short / Outdoor sensor open |
| C2849 | Fault C; Chassis Code Problem is controller area network wiring bus and modules. fault two; MFG – Manufacturer Specific Fault eight; Ignition System Or Misfire fault four; BBV Sensor Circuit Low Voltage fault nine; Kick-Down Switch Failed Short |
| U2453 | Fault U: Network Code Problem is climate control system, lighting, airbags, etc.. fault two; MFG – Manufacturer Specific fault four; Transmission fault five; TP Sensor Learn Not Complete fault three; Transmission Control Module Reprogrammable Memory |
Grant Boiler Error Description | |
| Grant Fault | Fault Description |
| Boiler Will Not Start | Low pressure cut-out activated No electrical supply to burner Check controls are switched on and calling for heat Boiler thermostat and/or overheat thermostat faulty |
| Burner lights but goes to lock-out | Fault with burner No fuel supply Oil tank empty Fire valve closed Fire valve closed. Fuel line filter is blocked Oil supply line is air locked Excessive combustion air Fault with burner |
| Burner fires but smoke visible from flue or high smoke number | Insufficient combustion air supply to burner Incorrect or faulty nozzle fitted Fuel pressure too high |
| Burner pulsates | Insufficient combustion air supply to burner |
| Burner cycles On and Off | Contaminated combustion air (balanced flue) Insufficient oil flow to burner due to restriction in supply line Excessive combustion air |
| Fumes and puffing on starting | Flue is blocked Insufficient flue draught Flue pipe or liner is too large or existing stack is unlined Insufficient combustion air supply to burner |
| Flame slow to stabilise on starting | Insufficient combustion air supply to burner Fuel pressure too low |
| Oil smells | Oil leak in supply line or burner |
| Combustion fume smells | Leak around boiler cleaning door Burner not correctly fitted on mounting flange Burner seal ‘O’ ring damaged or missing. Leakage around flue connection |
| Overheat thermostat operating | Faulty boiler thermostat Thermostat sensor not connected to printed circuit board (PCB) – Vortex Combi only Faulty overheat thermostat |
| No water flowing from hot tap | Mains water supply is not connected to cold water inlet of boiler One or more isolating valves, stop cocks, etc. in the pipework are closed The cold water isolating valve in the boiler is closed There is a blockage (or blockages) in the pipework |
| No hot water operation | Hot tap is not connected to hot water outlet of boiler Insufficient flow of water through boiler Boiler cold water and hot water connections reversed Thermostatic mixing valve incorrectly fitted Pump is not operating in hot water mode Diverter valve microswitch(es) faulty Diverter valve microswitches not operated Diverter valve seized Diverter valve diaphragm failed |
| Low water temperature at tap | Flow of water through boiler too high Boiler thermostat incorrectly set Thermostatic mixing valve incorrectly set Faulty boiler thermostat Pump speed setting too low Pump is incorrectly fitted |
| Hot water for short period only | Burner not firing for hot water (after a short time) Burner oil pressure set too low at oil pump Incorrect oil nozzle fitted to burner |
| No operation on heating | Timeswitch either not set, or not in an ‘ON’ period Timeswitch not operating Faulty timeswitch Faulty timeswitch switch contacts Timeswitch OK but not switching boiler on Heating switch set to ‘HOT WATER ONLY’ Room thermostat not calling for heat Faulty room thermostat No room thermostat or external timeswitch connected to boiler |
| Flow temperature low | Boiler thermostat is set too low Boiler thermostat faulty Boiler is underfired Combustion setting of burner incorrect Boiler heat exchanger is sooted up |
| Grant Vortex / Eco / Pro Boiler Error Codes | |
| Fault Code | Cause of Problem |
| No fuel supply | Insure that an adequate supply of fuel is available and that the fuel supply valve is open – check the condition of the fuel filter and clean if necessary, ensure fuel supply is reaching burner and vent pump |
| No Electricity Supply | Ensure electricity supply to the boiler is switched on and that all controls are calling for heat – ensure that the overheat thermostat has not tripped, reset if necessary and check the mains supply |
| Burner not starting – fuel and electricity supplies present | Reset boiler on the burner control box – if it is lit refer to burner fault finding charts |
| Burner lights but goes to lock out | If the flame is unstable check the combustion setting |
| Visible smoke from flue or high smoke number | Insufficient air supply. Check the air damper setting and the condition of the fan check room ventilation, check the nozzle size and type, fuel pressure may be too high, check and adjust |
| Burner pulses | Insufficient air supply – check the air damper setting and the condition of the fan, check room ventilation |
| Flame slow to stabilise during start up | Insufficient air supply – Check the nozzle size and type as fuel pressure may be too low, check and adjust insufficient draught clean boiler heat exchanger and check condition of flue |
| Water temperature low | Undersize nozzle and or low fuel pressure check condition of boiler heat exchanger and clean if necessary. Check the boiler thermostat, check the combustion setting, check the condition of the fuel filter |
| Boiler operating an overheat thermostat | Faulty boiler thermostat – no circulation, check circulating pump, check for air lock |
| Fumes and puffing during starting | Check the condition of the chimney to ensure it is not blocked and is high enough to produce the required draught – check that there is an adequate air supply near the burner fan is not drawing products out of the burner |
| Oil odours | Check all fuel line connections and remake as necessary |
| Combustion fumes smell | Check boiler cleaning cover and seal are correctly fitted, check burner is correctly fitted onto flange, check flue is correctly sealed into flue outlet of boiler, check the condensate pipe and trap are operating correctly |
Grant Vortex Blue Error Codes | |
| Fault Code | Cause of Problem |
| Red blinking light | Presence of a false flame signal before heat request |
| Red blinking light | Presence of false flame signal during pre-purging |
| Red blinking light | Presence of false flame signal during post-purging or pre-heating |
| Red steady on | UV sensor defective or dirty oil valve defective fault – ignition transformer badly regulated burner, oil fuel not present |
| Red blinking light | Badly adjusted burner, oil valve defective or dirty UV sensor defective or dirty |
| Red and orange blinking inverted | Error with oil valve internal control circuit that drives the oil valve error |
| Red green blinking inverted | Internal memory error |
| Orange green blinking inverted | Check presence of voltage, check the condition of the fuses, check that safety thermostat is not in lockout |
| Off | Eliminate the extraneous light |
| Off | Check that plugs and sockets are connected properly |
| Red blinking light | Eliminate the extraneous light |
| Red steady on | Clear it / replace it / check the pressure and output of the fuel / check air output change nozzle check the coil od solenoid valve |
| Green blinking light | Set the air according to the instructions of the manual or replace |
Grant Vortex Eco Error Codes | |
| Fault Code | Cause of Problem |
| Motor fails to run | No electrical supply to boiler check on/off switch is on – it should be neon lit |
| Lock-out light not lit | Fuse has blown – check reason for failure |
| Motor fails to run | No power to burner motor |
| Burner lock out | Burner motor capacitor fault check and replace if necessary |
Grant Vortex Pro Combi Error Codes | |
| Fault Code | Cause of Problem |
| Power supply | Check that fused spur for heating system and boiler is switched on – check that the electricity supply has not failed |
| Heating system controls | Check that the timer or programmer is working and set to an on period |
| Boiler controls | Check boiler on/off switch is set to on – check that power indicator on and control panel is lit |
| Burner | Check the burner lockout reset button is lit, if yes press the reset button to start the burner if burner fails call an engineer |
| Heating system | Check the heating system water pressure |
| power | If the boiler is not lit it could be a problem with power supply to the boiler switched off or possibly blown a fuse |
| DHW pump | If flashing this indicates either a store thermistor or PCB fault |
| Flow | If the boiler is not lit when a hot tap is opened this could mean there is a lack of water flow or possible flow switch problem |
| Demand | If not lit this indicates either timer or programmer is not calling for hot water / switch is not set to constant |
| Burner | If flashing this indicates a PCB fault |