FAULT FINDING AND DIAGRAMS
Greenstar FS CDi
ErP
6720818079 (2016/04)
41
7.3
Fault finding
Preliminary checks:
Preliminary electrical system checks are the first electrical checks to be carried out during a fault finding procedure.
On completion of the Service/Fault finding task which has required the breaking and remaking of electrical connections, check:
a) EARTH CONTINUITY, b) SHORT CIRCUIT CHECK, c) POLARITY, d) RESISTANCE TO EARTH.
Condensate pump Indicator lights
The condensate pump has indicator lights that show the operation status or a fault condition.
Fig. 62 Condensate pump indicator lights
▶ This fault finding information is for guidance only. Worcester Bosch cannot be held responsible for costs incurred by persons not
deemed to be competent.
▶ The electronic control system for this boiler incorporates a blue central indicator. This normally confirms the permanent mains
supply, but, by flashing during a fault, provides a guide to the cause as listed.
BOILER - FAULTS AND CONDITIONS
Display code:
Fault description
Check, repair/replace as necessary
A8
EMS communication error
Check all electrical connections, replace control board.
b1
Code plug not detected
Insert code plug correctly, test and replace as necessary.
b2, b3, b4, b5,b6 Data error
Replace control board.
b7
Burner control error
Replace control board.
C6
Fan defect
Check fan, lead, and connector, replace as necessary.
d3
External temp limiter
Connect terminals 8 & 9 on ST8.
d5
Condensate pump failure
See condensate pump table.
EA
Flame not detected
Check gas is present, ignition electrodes and harness, flame sense electrode and harness,
and operation of gas valve. Replace as necessary.
E2
Primary NTC defect
Check primary NTC sensor and leads, resistance across NTC should be between 36k to 1k
Ω
E9
OH stat tripped
Check system pressure, overheat thermostat, and pump operation. Replace as necessary
F0
Internal error
Check all electrical connections, replace control board as necessary.
F1
ROM error check
Check all electrical connections, replace control board as necessary.
F7
Flame detected after appliance
shut off
Check flame sense electrode and harness, and control board for signs of water damage.
Replace as necessary
FA
Flame detected after gas shut off
Check flame sense electrode and harness, and control board for signs of water damage.
Check gas valve operation.Replace a s necessary
Fd
Reset button pressed
Press reset button again
6720818077-27.1W
o
CONDENSATE PUMP -
OPERATING LIGHTS AND FAULT CONDITIONS:
Ready for operation = Steady green light
Fault = Red light Pump running = Flashing green light
Operating lamps Cause
Solution
Green
Red
Off
Off
Mains supply not
connected
Power failure
Connect mains supply
Check mains and fuse/
circuit breaker
Flashing Flashing Dry-run
(possible air in pump)
Pump restarts
automatically after one
minute
On
Flashing Pump blocked
Visually inspect the pump
inlet and tank.
Remove or rinse out any
dirt or foreign bodies
On
On
Level exceeds alarm
level
Discharge hose or non-
return valve blocked
Possible kink in discharge
hose (clean or remove
kink if applicable)
Off
Flashing Pump blocked and
alarm level exceeded
Visually inspect the pump
inlet and tank.
Remove or rinse out any
dirt or foreign bodies
