29
NOTE:
This information is for guidance only. Worcester Heat Systems cannot be held responsible for costs incurred by persons not
deemed to be competent.
Preliminary Checks:
Electrical system checks are the first actions to be carried out during a fault finding procedure. On completion of the service or a fault
finding task which ha s necesitated the breaking and remaking of electrical connections, check (a) Earth Continuity, (b) Short Circuit,
(c) Polarity, (d) Resistance to Earth.
The electronic control system for this appliace uses a facia display which shows, in normal operation, the central heating flow
temperature. If a fault exists then the diagnostic system displays the appropriate fault code.
NOTE: Check that the appliance code plug is correctly fitted before starting any detailed examination.
State : 1
Waiting correction by external appliance
2
Boiler stopped until fault disappears
3
Boiler works with limited function
4
Lock-out does not reset
18. Fault Finding
Display
A5
A7
AC
b1
C1
C4
C6
CC
d3
E0
E2
E9
Condition
Circuit break or short circuit in the
constant hot water temperature
sensor.
Circuit break or short circuit in the
dhw temperature sensor.
No electrical connection between the
controller (TA211E) and the control
board.
Code plug.
Air pressure switch contacts open
when appliance is operating or fan
speed to slow.
Air pressure switch contacts do not
open.
Air pressure switch contacts remain
open.
Circuit break between outside
temperature sensor and control unit.
Internal fault on control board.
Circuit break or short circuit on ch
temperature sensor.
Safety temperature limiter has
tripped
Action
Check the sensor leads for
continuity.
Check the sensor leads for
continuity.
Check the lead and connector from
the controller for continuity.
Insert code plug correctly or replace.
Check fan, controller, air pressure
switch and connector tube.
Check air supply, fan, control unit, air
pressure switch. Check for
correct flue length.
Check sensor and leads for
continuity.
Replace control board.
Check sensor and leads for
continuity.
Check ch temperature sensor, pump,
fuses or control board, vent
appliance.
State
2
2
2
3
4
2
4
Summary of Contents for Greenstar ZWBR 11-25 A31
Page 31: ...31 ...