Glow-worm 56/3e Back Boiler - Manual (Page 25)

25 221725B
Ensure all connections are correctly made, that gas supply is available free of obstruction
and purged of air. Ensure that external controls, if fitted, are calling for heat.
YES
YES
Does sparking take
place, does milli-voltage
increase towards 5mV?
Pilot not lit.
Check condition of
electrode and HT lead.
Replace as necessary.
≈
30 seconds after a call
for heat, does the
control board (PCB)
start to spark.
NO
Is milli-voltage > 5mV?
NO
Faulty thermocouple.
Replace.
Faulty gas control valve.
Replace.
Appliance working
satisfactorily.
NO
YES
Faulty control board (PCB).
Replace.
Faulty control board (PCB).
Replace.
Faulty control board (PCB).
Replace.
NO
Does green light on
lockout reset button
illuminate and sparking
stop when milli-voltage
is >5mV?
YES
Is there 230V at
both connections on
the thermostat control
with reference
to neutral?
Is there 230V at
PIN EV2 on CN3 on
control board (PCB)
with reference to neutral?
YES
Check continuity of lead
from control board (PCB)
to gas control valve,
is there continuity?
YES
NO
NO
Faulty thermostat
control. Replace.
NO
NO
Faulty lead.
Replace.
NO
YES
The flue blockage
safety device
has operated, the main
burner has gone out.
Check adequate
ventilation is available,
check flue has not
become blocked.
YES
Turn control thermostat
knob to maximum.
Does main burner light?
YES
Does red light on
lockout reset button
illuminate?
Press lockout reset
button. Ignition should
take place, appliance
should work satisfactorily.
Connect a multimeter
set to mVDC to pins
TC-GND and TC-SGN
on CN1 on the
control board (PCB).
START
9 Fault Finding
Diagram 9.1 ELECTRICAL FAULT-FINDING BACK BOILER
7301