
Fault finding and diagnosis
73
Greenstar 4000 – 6 720 891 161 (2020/09)
262
V
System fault boiler electronics / basic
controller
▶ Reset appliance electronics (factory reset).
▶ Check the electrical connections on the board (check for loose wires etc.).
▶ Replace the control unit.
263
V
System fault boiler electronics / basic
controller
▶ Reset appliance electronics (factory reset).
▶ Check the electrical connections on the board (check for loose wires etc.).
▶ Replace the control unit.
265
B
Heat demand lower than energy supplied
Operating message, is not a fault.
• The boiler's ignition sequence alone is sufficient enough to maintain room
temperature.
• The modulating heat demand is higher than the minimum modulation factor of the unit.
The unit switches to proportional control.
268
O
Relay test was activated
Operating message, is not a fault.
• Appliance in component test mode.
269
V
Flame monitoring
▶ Restart the appliance to see if the problem re-occurs.
▶ Check the electrical connections on the board (check for loose wires etc.).
▶ Replace the control unit (PCB).
273
B
Operation of burner and fan interrupted
Operating message, is not a fault.
• The burner and fan have been running continuously for 24 hours and have been shut
down briefly for an appliance electronic inspection
281
B
Pump stuck or running in air
▶ Check primary system water pressure.
▶ Check for air in the system and vent the pump.
▶ Check for circulation within heating system.
▶ Check hydraulic connections to the pump.
▶ Check wiring and operation of the pump, replace if necessary.
283
O
Burner starting
Operating message, is not a fault.
• Burner is starting.
284
O
Opening air/gas ratio control valve/oil
solenoid valves
Operating message, is not a fault.
• Gas valve is opening.
305
O
Boiler in hot water anti-cycle mode
Operating message, is not a fault.
• Anti-cycle mode, domestic hot water post-heat function. Following a domestic hot
water demand the boiler runs for 30 seconds or until the target temperature is met.
– Diverter valve is held in the hot water position for a period of time.
– If no domestic hot water demand is requested then check for false demands on the
cold water inlet.
306
V
Flame signal after closing the fuel supply
Tip: Ensure the working pressure returns immediately to the standing pressure when the
gas valve closes.
▶ Check the gas valve, replace if required.
▶ Check electrodes and connecting leads, replace if required.
▶ Replace the appliance electronics.
353
O
Test non-volatile lockout
Operating message, is not a fault.
• If the boiler has been operating for 24 hours without a 20-minute off period, the boiler
will not respond for a period of time whilst it undertakes diagnostics checks on the fan.
357
O
Flame signal after closing the fuel supply
Operating message, is not a fault.
• Venting/air purge program has been automatically activated.
358
O
Anti-seizing functn. active
Operating message, is not a fault.
• Blocking protection for the heating pump and diverter valve active.
– The purpose of component kick is to ensure that hydraulic components such as
pumps will not get stuck by giving these functional components a “kick”, i.e. they
are briefly turned on after a period of inactivity.
– After power up every 24 hours the appliance will do a component kick, where the
pump will run for 10 seconds.
– If the appliance is already in a CH or DHW heat request, these heat demands will be
prioritised over component kick. But once the heat demand has ended the
component kick will take place.
– If this causes nuisance then please power the appliance off and on again at a more
suitable time; the daily kick will then occur at the time the appliance is turned on
again.
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ry Fault text on the display, description
Remedy