Bosch Greenstar 12i Service Manual download pdf (Page 65)

FAULT FINDING AND DIAGNOSIS

6 720 644 743b (2011/08)

Slow flash

(mostly

off, flashes

on)

Flashing

(reset

required)

Ignition lockout B Gas present and at correct pressure?

B 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)

B Combustion CO

level.

B Flue condition.

– Blocked flue?

B Blocked condensate pipe or frozen condensate.

B Gas valve adjustment.

B Ignition electrodes/harness/connections.

– Check for condition and resistance of leads

(approximately 2100 Ω)

B Otherwise replace control board

Slow flash

(mostly

on, flashes

off)

Flashing

(reset

required)

Flue overheat B Heat exchanger baffles removed and not refitted.

Heat exchanger

overheat

B Heat exchanger blocked

B Water pressure

B All air vented

B Pump/harness/connections.

B Water leaks/blockage

B Safety thermostats/low voltage wiring harness/connections

B Otherwise replace control board

Fast flash Off Volatile lockout -

Fan does not run

B Temperature sensors

– Check condition and continuity of leads and resistance of

sensors (approximately 2100 Ω)

B Fan

– 230V a.c. across the live (purple) and neutral (brown)

B Fan lead

– Check continuity

B Code plug

– Is code plug missing or not inserted properly.

Fast flash Flashing Internal fault Replace control board

2 pulses No light Not a fault code Service mode selected to minimum, press service button to

return to normal

5 pulses No light Not a fault code Service mode selected to maximum, press service button to

return to normal

Blue light

indication

Lockout

reset button

Fault Possible solution/check

Tab. 28

1 2 ... 60 61 62 63 64 65 66 67 68 69 70 71 72

Comments to this Manuals

No comments

Bosch Greenstar 12i Service Manual Page 65

Comments to this Manuals

Related products and manuals for Water heaters & boilers Bosch Greenstar 12i