Fault finding and diagnosis
77
Greenstar 2000 – 6 721 820 552 (2021/02)
263
V
Program sequence error
▶ Restart the appliance to see if the problem re-occurs.
▶ Check the electrical connections on the board (check for loose wires etc.).
▶ Check the code plug, if present, is not damaged.
▶ Replace the code plug, if present and required.
▶ Replace the control unit (PCB).
264
B
Air handling failed during operation
▶ Reconnect the fan plug properly, perform reset.
▶ Replace fan.
▶ Mains voltage must correspond to the default value.
▶ Remove any blockages in the flue system.
▶ Check venturi/injector for potential blockage.
265
O
Heat demand lower than energy supplied
Operating message, is not a fault.
268
O
Relay test was activated
Operating message, is not a fault.
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).
270
O
Starting up boiler
Operating message, is not a fault.
273
O
Operation of burner and fan interrupted
Operating message, is not a fault.
275
O
Boiler electronics in test mode
Operating message, is not a fault.
281
B
Pump pressure increase too low
▶ Check the flow pressure in system.
▶ Check the system for circulation issues (air locks, blockage, restriction).
▶ Check that the tacho/PWM plug, if present, for the circulation pump is fitted correctly.
▶ Check the tacho/PWM cable, if present, for continuity and replace the tacho/PWM cable
if required.
▶ Replace the pump.
283
O
Burner starting
Operating message, is not a fault.
284
O
Opening air/gas ratio control valve/oil
solenoid valves
Operating message, is not a fault.
305
O
Boiler in hot water anti-cycle mode
Anti-fast cycle mode, domestic hot water keep warm function.
▶ Diverter valve is held in the hot water position for a period of time.
▶ 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 supply to the property and the inlet on the gas valve (check drop on inlet).
▶ Check the gas valve is not passing and replace if required.
▶ Replace the PCB.
323
–
BUS signal cannot be processed
▶ Check connection to EMS controls, including 2-core cable if hard-wired.
▶ Check and replace PCB.
328
V
Brief mains voltage failure
▶ Check for voltage interruption between electrical wiring system of the building and the
appliance.
341
B
Temperature rise at boiler too rapid
▶ Open isolation valves.
▶ Connect plug to pump.
▶ Replace pump.
▶ Ensure circulating pump is set on Constant speed mode - curve III.
342
B
Temperature rise during hot water mode too
rapid
▶ If the water pressure is too low, top up with water and vent the system.
▶ Ensure isolation valves are open
▶ Check and replace diverter valve
350
B
Short-circuit at flow temp. sensor
▶ Check and replace flow temperature sensor and harness
Section 13.2.
▶ Check and replace the connecting lead to the flow temperature sensor.
▶ Check and replace control unit/burner control unit.
351
B
Flow temp. sensor interrupted
▶ Connect the plug to the flow temperature sensor.
▶ Check and replace flow temperature sensor and harness
Section 13.2.
▶ Check and replace the connecting lead to the flow temperature sensor.
▶ Check and replace control unit/burner control unit.
353
–
Test non-volatile lockout
Device may not start temporarily, never been off for 20 min for 24 h.
354
–
Test volatile lockout
Overpressure setting is detected.
356
B
Power supply for the boiler is too low
▶ Establish supply voltage of at least 196 VAC.
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Remedy
