39
221469B
3 Fault Finding
ELECTRO/MECHANICAL FAULT FINDING
Diagram 3.9
5667
Does clock keep time
Set clock to off period. Is there continuity
across common and heating on
Clock in order if no
central heating refer to
main fault finding
Isolate electrical supply set clock to on period
Is there continuity across
common and heating on
Faulty clock
replace
No
No
No
Yes
Yes
Yes
CLOCK FAULT FINDING
If a mains potential room thermostat is connected, make sure that the switch line is connected to pin 1 in
the 5 pole connector.
Check continuity of clock harness, make sure an electrical supply is available make sure that remote
controls are calling for heat.
Make sure the override switch if fitted is in the " " position
5669
If a mains potential room thermostat is connected, ensure that the switch live is connected
to Pin 1 in the 5 pole connector.
Check continuity of clock/timer harness, ensure an electrical supply is available,
ensure that remote controls are calling for heat.
Isolate the boiler from electrical supply remove outer case.
Disconnect and insulate the purple cables
from heating common and heating on.
Switch on electrical supply,
is there a display on clock/timer?
NO
Clock/timer in order if no central heating,
refer to main fault finding.
Advance clock/timer until a demand is indicated
Is there now continuity between heating
common and heating on?
YES
Faulty clock/timer.
Replace.
Faulty clock/timer.
Replace.
YES
YES
YES
NO
DIGITAL CLOCK/TIMER
Diagram 3.9
Disconnect and insulate the yellow cables from
heating common and heating on.
To Next Page
Loading...
Need help?
General