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15.0
FAULT FINDING
Carry out initial fault finding
checks
1. Check that gas, water and electrical supplies are available at the boiler. Electrical supply = 230V
-
50 Hz.
CH water system pressurised to 0.5 bar when the boiler is cold. The preferred minimum gas pressure is 19.5mbar (natural gas),
or 36mbar (propane).
2. Carry out electrical system checks, i.e. Ground Continuity, Resistance to Ground, Short Circuit and Polarity with a suitable meter.
NOTE: These checks must be repeated after any servicing or fault finding.
3. Ensure all external controls are calling for heat and check all external and internal fuses. Before any servicing or replacement of parts
ensure the gas and electrical supplies are isolated.
Refer to Section 13.1 "Illustrated Wiring Diagram" for position of numbered terminals
Central Heating
-
Follow operational sequence
Turn selector to .If rF=
Q
neon illuminated
YES
Turn
.If
thermostat
to max.
Pump runs
YES
Air pressure
switch proved
YES
Spark at ignition
electrodes for up to 10
seconds
YES
I
j
Burner on
h
neon
illuminated
YES
Burner extinguishes
after 10 seconds
NO
Burner output
modulates until set
temperature is reached
NO
Go to section 'A'
Go to section 'B'
YES
NO
External controls and,
where fitted, integral timer
calling for heat
NO
Go to section 'c'
Turn the selector switch to
the 'Reset' position and
hold for at least 2
seconds. If regular
resetting is required, or
appliance still does not
operate, investigation is
necessary
NO
Go to section 'E'
NO
A
illuminated
YES
NO
Go to section 'F'
YES
Go to section 'I'
NO
Go to section 'G'
Fan stops
NOTE: When instructed to turn the Selector
to the reset position turn the Selector Switch
fully anticlockwise against the spring
pressure and hold for 2 seconds to reset the
boiler.
Ensure controls are set to
demand and verify the
contacts are closed
Go to sections 'J', 'L' & '0'
Turn selector to the reset
position. If the light does
not extinguish go to
sections H & K
Pump stops
Operation sequence
correct
41
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