Unigas C70N US, Manual Of Installation - Use - Maintenance

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PART V: MAINTENANCE
42
TROUBLESHOOTING GUIDE Gas operation
BURNER DOESN'T LIGHT
* No electric power supply * Restore power supply
* Main switch open * Close switch
* Thermostats open * Check set points and thermostat connections
* Bad thermostat set point or broken thermostat * Reset or replace the thermostat
* No gas pressure * Restore gas pressure
* Safety devices (manually operated safety thermostat,
pressure switches and so on) open
* Restore safety devices; wait till boiler reaches operating
temperature then check safety device functionality.
* Broken fuses * Replace fuses. Check current absorption
* Fan thermal contacts open (three phases motors only) * Reset contacts and check current absorption
* Burner control lock out
* Reset and check its functionality
* Burner control damaged * Replace burner control
GAS LEAKAGE: BURNER LOCKS OUT
(NO FLAME)
* Gas flow is 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
* Wrong setting of flame detector * Adjust flame detector
* Flame detector damaged * Replace 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 closed * Open the butterfly valve
* Maximum pressure switch 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
PHASE-TO-PHASE SUPPLY OR PRESENCE OF
VOLTAGE ON NEUTRAL*
* Lights up and freezes * In such cases, insert an RC circuit (our code 2531003).