25
12.0 Fault Finding
Is there permanent live
to the boiler?
Is the “Power On” neon
illuminated ?
NO
YES
NO
YES
Is there 230V at L & N
connections on the neon?
Electrical fault external to
boiler
Replace neon
CARRY OUT THE FOLLOWING PRELIMINARY CHECKS BEFORE
COMMENCING FAULT FINDING
1. Check that gas, water and electrical supplies are available at the boiler.
Electrical supply = 230V ~ 50 Hz. The preferred minimum gas pressure is
19.5mbar (natural gas).
2. Carry out electrical system checks, i.e. Ground Continuity, Resistance to
Ground, Short Circuit and Polarity with a suitable meter. Note: Repeat these
checks after servicing or fault finding.
3. Ensure all external controls are calling for heat and check all external and
internal fuses. Before servicing or replacement of parts ensure the gas and
electrical supplies are isolated.
YES
Does the On/Off button
illuminate when pressed in?
Is there 230V at L & N of
the On/Off button?
NO
START
NO
Is there 230V at SWL & N
on terminal strip?
Check supply from
external controls
YES
Replace On/Off Button
NO
Check boiler internal
wiring
YES
NO
Internal electrical fault on
boiler
YES
