Grant
Fault Codes

Listed below are the common Grant fault codes as described by the boiler manufacturer along with a possible cause.

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 orcircuit 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

FREE BOILER MANUALS

GrantFault Codes

Grant Boiler Error Codes

Grant Boiler Error Description

Grant Vortex / Eco / Pro Boiler Error Codes

Grant Vortex Blue Error Codes

Grant Vortex Eco Error Codes

Grant Vortex Pro Combi Error Codes

Grant
Fault Codes