Glow-worm 23c - Manual (Page 26)

26 2000225000B
16 Fault Finding
Before trying to operate the boiler make sure that :
• All gas supply cocks are open and that the gas supply has
been purged of air.
• The heating system pressure is at least 1 bar.
• There is a permanent mains supply to the boiler.
• The fuse on the PCB is intact.
WARNING. Always isolate the boiler from the electrical supply
before carrying out any electrical replacement work.
Always check for gas soundness after any service work.
Should there be any doubt about the voltage supply to any of
the components, it is possible to carry out a simple electrical
test to ensure all is operational in that area.
To carry out the electrical test, gain access to the main Printed
Circuit Board (PCB), as described previously, and measure
the voltages according to table 2.
IMPORTANT: On completion of the fault finding task which
has required the breaking or remaking of the electrical
connections, the continuity, polarity, short circuit and resistance
to earth checks must be repeated using a suitable multimeter.
TYPE OF FAULT CHECK
No domestic hot water or central heating • 230V supply
(No flashing warning light on control panel) • Is fuse blown
• Loose connections on control board (PCB)
• Faulty control or interface board (PCB's)
No domestic hot water or central heating • Water pressure
(A flashing warning light on control panel) • Shortage of air or gas
• Faulty temperature sensor
• Overheating
• Wrong flue length
• Connections on air pressure switch (electrical or tubes)
disconnected
No hot water but central heating ok • Loose connections at hot water flow sensor.
• Faulty hot water flow sensor.
• Faulty control board (PCB).
Voltage Measured value Measuring point
230 Volt 230V AC Between terminals H8.1 and H8.2
24 Volt maximum 33V DC Between terminals J5.3 and J15.1
minimum 20V DC
18 Volt 18V ± 1V Between terminals J2.9 and J2.10
Display 5V ± 0.5V Between terminals J13.4 and J13.1
Table 2