40 LT5052 (ISS 5)
FAULT FINDING CHART
Press & release fan 'ON
switch and observe light.
Check mains supply (see
Mains Check). Is mains
supply OK?
Correct mains
supply fault.
On pressing switch did
red light illuminate?
Replace faulty fan control unit.
When switch was
released did red light
remain illuminated?
After a short time
(approx. 5-10 sec.) is red
light on fan control
extinguished?
As red light extinguishes
does fan speed reduce?
Operate gas control. Is
gas available at pilot?
On releasing control knob
does pilot remain alight
after holding in for
approx. 20 sec?
While the fire is alight
press the fan control OFF
switch. Is the fan turned
off?
Is gas too oxy-pilot shut
off?
Appliance control system
OK?
Check pressure switch
operation. (Pressure Switch
Check. Is pressure switch
OK?
Check fan operation (see Fan
Check). Is fan OK?
Is flue pipe outlet clear of
restriction / blockage?
Correct fault/replace fan unit.
Correct gas supply fault.
Correct fault with ignition
system.
Remove thermocouple leads
from the fan control unit and
insert test leads. With the
meter set on low ohm scale
operate the ON switch. Does
meter read less than
0.5ohms?
Replace oxy-pilot / gas control
as appropriate.
Check fan wiring and/or
replace faulty fan control unit.
Replace faulty gas control.
Correct fault /
replace pressure
switch.
Correct fault /
replace fan unit.
Remove blockage
and or restriction.
Replace faulty fan
control unit.