12
Fault finding
Greenstar FS CDi
ErP
– 6720919078 (2015/12)
6.1
Error codes
6.2
Extreme cold weather
In some instances where the condensate pipe work is run
externally or in an unheated area, such as a garage, the
condensate pipe work can be at risk of freezing, even if well
insulated.
A frozen/blocked condensate pipe will cause the boiler to shut
down.
If the condensate pipe has frozen:
▶ Locate the blockage.
It is likely that the pipe is frozen at the most exposed point
outside the building or where there is an obstruction to
flow.
This could be the open end of the pipe, at a bend or elbow,
or where there is a sag in the pipe in which condensate can
collect.
The location of the blockage should be identified as closely
as possible before taking further action.
▶ Thaw the frozen pipe.
The pipe can be thawed by applying a hot water bottle, a
microwaveable heating pack (the sort used for muscular
aches and pains) or a cloth soaked in hot water to the
exterior of the pipe, close to the point of blockage.
Hot water, but not boiling, can also be poured onto the pipe
from a watering can or similar container.
▶ Once the pipe has been thawed the boiler must be reset,
press the reset button for five seconds and wait two to
three minutes for the boiler to restart.
▶ If the boiler does not restart, contact Worcester, Bosch
Group Appointments Team (see back cover for details).
▶ Contact your installer in order to find a permanent solution
to the problem.
When calling Worcester, Bosch Group, you
may be asked for the error code. This Table is
for you to help identify the possible cause of
the fault.
▶ Do not try to rectify any of the faults listed
below by yourself.
▶ Contact a Worcester, Bosch Group service
engineer, or other Gas Safe registered
engineer.
Error code
Description
A7
Hot water NTC sensor defective.
A8
Break in communication to weather
compensating clip-in control or Greenstar
Comfort II RF
b1
Code plug not detected.
C6
Fan speed too low.
d5
Condensate pump fault
E2
CH flow NTC sensor defective.
E9
Safety temp. limiter in CH flow has tripped.
EA
Flame not detected.
Check, if it is safe to do so:
•
if gas is on in the house
•
for frozen condensate pipe
•
for blocked flue outlet
F0
Internal error.
F7
Flame detected even though boiler switched
off.
FA
Flame detected after gas shut off.
Fd
Reset button pressed by mistake.
SE
Service required
U1
Boiler flow temperature is too high,
the boiler will shut down until it has cooled
down
U2
U3
WARNING:
Falling hazard!
Failure to follow this guidance may result in
personal injury.
▶ Only attempt to thaw a condense pipe that
is at ground level, and that is easily
accessible.
▶ Never attempt to thaw a condense pipe
that is at height.
CAUTION:
Pipe damage
▶
DO NOT
use boiling water to thaw the
condensate pipe!
CAUTION:
Slip hazard
▶ Ensure that the subsequent freezing of any
water does not result in a slip hazard
