Worcester GREENSTAR 24i Junior Installation, Commissioning And Servicing Instructions page 54

FAULT FINDING AND DIAGNOSIS
Blue light Lockout reset
indication button
Slow flash Flashing (reset
(mostly off, required)
flashes on)
Slow flash Flashing (reset
(mostly on, required)
flashes off)
Fast flash Off
Fast flash Flashing
2 pulses No light
5 pulses No light
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Fault Possible solution/check
Ignition lockout ▶ Gas present and at correct pressure?
▶ Gas valve
– Check that there is 35V d.c. to each solenoid
– Check the resistance of each solenoid:
Top solenoid = 380 Ω ± 10% (342 - 418 Ω)
Bottom solenoid = 190 Ω ± 10% (171 - 209 Ω)
▶ Combustion CO
▶ Flue condition.
– Blocked flue?
▶ Blocked condensate pipe or frozen condensate.
▶ Gas valve adjustment.
▶ Ignition electrodes/harness/connections.
– Check for condition and resistance of leads
(approximately 2100 Ω)
▶ Otherwise replace control board
Flue overheat ▶ Heat exchanger baffles removed and not refitted.
Heat exchanger overheat ▶ Heat exchanger blocked
▶ Water pressure
▶ All air vented
▶ Pump/harness/connections.
▶ Water leaks/blockage
▶ Safety thermostats/low voltage wiring harness/connections
▶ Otherwise replace control board
Volatile lockout - ▶ Temperature sensors
Fan does not run
– Check condition and continuity of leads
▶ Fan
– 230V a.c. across the live (purple) and neutral (brown)
▶ Fan lead
– Check continuity
▶ Code plug
– Is code plug missing or not inserted properly.
Internal fault Certain PCB/software related faults can be reset by initiating a PCB reset.
This is achieved by pressing and holding in the service and eco buttons together for
approximately five seconds, until all buttons on the fascia flash to show the reset has
completed
Replace control board
Not a fault code Service mode selected to minimum, press service button to return to normal
Not a fault code Service mode selected to maximum, press service button to return to normal
level.
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6 720 802 047 (2013/05)