Burner goes out due to the
intervention of the LIMIT
thermostat (LM).
Yellow light flashing
Excessive heat exchanger
temperature.
Check inlet gas pressure
Check burner head pressure
Check that gas type is suitable
for heater
Check injector size is correct for
the heater.
Excessive air temperature due
to poor air flow over heat
exchanger
Check the fan blades are clean
Check that the horizontal and
(vertical if fitted) louvers are
sufficiently open. (see in
installation section of manual)
Check that the fan speed is
correct and the air flow over the
chamber is sufficient..
Faulty thermostat
Replace thermostat
Faulty fan
Check fan capacitor
Check fan motor.
Intervention of thermal overload
on fan
Check electrical absorption
Replace fan motor
Faulty fan operation
Change fan control or SND
thermostat
Heater at lockout
Red lamp illuminated
Faulty ignition
Check inlet gas pressure
Check burner head pressure
Check that gas type is suitable
for heater
Check that gas line has been
purged correctly.
Faulty ionisation probe
Check electrical connection to
the probe.
Check probe is not cracked or
damaged
Change probe or probe lead
Faulty ignition electrode
Replace ignition electrode.
Faulty solenoid
Replace solenoid
Dirty gas filter
Clean filter
