PART IV: MAINTENANCE
46
TROUBLESHOOTNG GUIDE - Gas operation
BURNER DOESN'T LIGHT
* No electric power supply
* Wait until power supply is back
* Main switch open
* Close the switch
* Thermostats open
* Check set points and thermostat connections
* Bad thermostat set point or broken thermostat
* Set or replace the thermostat
* No gas pressure
* Restore gas pressure
* Safety devices (manually operated safety thermostat or
pressure switch and so on) open
* Restore safety devices; wait that boiler reaches its
temperature then check safety device functionality.
* Broken fuses
* Replace fuses. Check current absorption
* Fan thermal contacts open (only three phases)
* Reset contacts and check current absorption
* Burner control locked out
* Reset and check its functionality
* Burner control damaged
* Replace burner control
GAS LEAKAGE: BURNER LOCKS OUT
(NO FLAME)
* Gas flow too low
* Increase the gas flow
* Check gas filter cleanness
* Check butterfly valve opening when burner is starting
(only Hi-Low flame and progressive)
* Ignition electrodes discharge to ground because dirty or
broken
* Clean or replace electrodes
* Bad electrodes setting
* Check electrodes position referring to instruction
manual
* Electrical ignition cables damaged
* Replace cables
* Bad position of cables in the ignition transformer or into
the electrodes
* Improve the installation
* Ignition transformer damaged
* Replace the transformer
BURNER LOCKS OUT WITH FLAME PRESENCE
* Bad flame detector set
* Flame detector damaged
* Replace or adjust flame detector
* Bad cables of flame detector
* Check cables
* Burner control damaged
* Replace burner control
* Phase and neutral inverted
* Adjust connections
* Ground missing or damaged
* Check ground continuity
* Voltage on neutral
* Take off tension on neutral
* Too small flame (due to not much gas)
* Adjust gas flow
* Check gas filter cleanness
* Too much combustion air
* Adjust air flow rate
only FOR LME22: BURNER CONTINUES TO PER-
FORM ALL ITS FEATURES WITHOUT IGNITING
THE BURNER
* Air pressure switch damaged or bad links
* Check air pressure switch functions and links
* Burner control damaged
* Replace burner control
BURNER LOCKS OUT WITHOUT ANY GAS FLOW
* Gas valves don’t open
* Check voltage on valves; if necessary replace valve or
the burner control
* Check if the gas pressure is so high that the valve
cannot open
* Gas valves completely closed
* Open valves
* Pressure governor too closed
* Adjust the pressure governor
* Butterfly valve too closed
* Open the butterfly valve
* Maximum pressure switch (if installed ) open.
* Check connection and functionality
* Air pressure switch doesn’t close the NO contact
* Check connections
* Check pressure switch functionality
THE BURNER IS BLOCKED AND THE EQUIPMENT
PROVIDES A LOCK CODE "CAUSE AIR PRESSURE
SWITCH FAULT"
* Air pressure switch damaged (it keeps the stand-by
position or badly set
* Check air pressure switch functionality
* Reset air pressure switch
* Air pressure switch connections wrong
* Check connections
* Air fan damaged
* Replace motor
* No power supply
* Reset power supply
* Air damper too closed
* Adjust air damper position
BURNER LOCKS OUT DURING NORMAL RUNNING
* Flame detector circuit interrupted
* Check wiring
* Check photocell
* Burner control damaged
* Replace burner control
* Maximum gas pressure switch damaged or badly set
* Reset pressure switch or replace it
THE BURNER STARTS AND AFTER A WHILE IT
REPEATS THE STARTING CYCLE.
* Gas pressure switch badly set
* Reset the pressure switch
* Gas filter dirty
* Clean gas filter
* Gas governor too low or damaged
* Reset or replace the governor
BURNER STANDS WHILE RUNNING WITHOUT ANY
SWITCHING OF THERMOSTATS
* Thermal contacts of fan motor open
* Reset contacts and check values
* Check current absorption
FAN MOTOR DOESN'T START
* Internal motor wiring broken
* Replace wiring or complete motor
* Fan motor starter broken
* Replace starter
* Fuses broken (three phases only)
* Replace fuses and check current absorption
BURNER DOESN'T SWITCH TO HIGH FLAME
* Hi-low flame thermostat badly set or damaged
* Reset or replace thermostat
* Servomotor cam badly set
* Reset servomotor cam
mechanical only
: SOMETIMES THE SERVOMOTOR
RUNS IN THE WRONG WAY
* Servomotor capacitor damaged
* Replace capacitor
