Unigas H455A, Manual

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PART IV: MAINTENANCE
40
BURNER DOESN'T LIGHT
* No electric power supply * Wait for electric 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
BURNER LOCKS OUT WITH FLAME
PRESENCE
* Flame detector dirty or damaged * Clean or replace flame detector
* Burner control damaged * Replace burner control
* Smoking flame * Reset combustion air flow rate
* Check the nozzle and, if necessary, replace it
* Check cleanness of combustion head
* Check chimney suction
* Check boiler cleanness
* Combustion head dirty * Clean combustion head
BURNER LOCKS OUT WITHOUT ANY
FUEL FLOW RATE
* No fuel * Fill the tank
* Pump joint broken * Check pump pressure
* Pump damaged * Check pump suction
* Replace pump
* Compressed air (or steam) too high * Released compressed air (or steam) pressure
* Oil metering valve not open far enough * Check air pressure
* Check servomotor position
* Oil valve not energized * Check wiring path or replace valve
* Fan motor not efficient * Adjust or replace the motor
* Fan or pump motor runs in the wrong way * Change rotation
* Obstructed nozzle * Clean or replace the nozzle
* Check valve in the tank locked or leaking * Clean or replace the valve
* Oil filter dirty
* Pump filter dirty * Clean filter
* Solenoid valve dirty or broken * Clean or replace solenoid valve
BURNER LOCKS OUT WITH FUEL FLOW
RATE (NO FLAME)
* Oil pressure too low * Reset oil pressure
* Nozzle dirty or damaged * Clean or replace nozzle
* Water in the tank * Take off all the water from the tank
* Clean all filters
* Suction too high * Check suction before pump. If necessary clean filters.
* Ignition electrodes grounded because dirty or damaged * Clean or replace electrodes
* Ignition electrodes badly set * Check electrodes position referring to instruction manual
* 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
PUMP TOO NOISY
* Suction too high (over 0,35 bar) (dirty filters, check valve in the tank locked,
and so on ...)
* Clean filters
* Replace check valve in the tank
* Flexible hoses damaged * Replace flexible hoses
* Air infiltration in the pipes * Take off all infiltration
* Pipe too long or too narrow * Increase line size
BURNER RUMBLES WHEN MODULA-
TING TO HIGH FIRE
* Burner is too lean * Adjust air-oil ratio
* Drawer assembly not set properly * Check drawer position
* Oil may be too hot * Check oil temperature
* Flame is blowing off head * Check head position
CARBON BUILD-UP ON THE FIRESIDES
OF THE BOILER
* Oil flame not retaining to head
* Dirty nozzle
* Clean the nozzle
* Oil spray impinging on burner head * Check position of the nozzle respect to the head
* Spray angle of the nozzle too wide * Reduce spray angle
FLAME IRREGULAR OR SPARKING
* Oil pressure at nozzle too low * Reset oil pressure
* Air flow rate too high * Adjust air flow rate
* Oil is too cold * Adjust oil temperature
* Dirt in the oil * Check filters
* Water in the fuel * Take off all the water
* Oil impingement on the combustion head * Drawer assembly far too rear
* Nozzle is not protruding through centerhole of air diffuser
* Oil flame not retaining to the head
* Nozzle dirty or damaged * Clean or, if necessary, replace the nozzle
BURNER LIGHTS BUT FLAME DOESN'T
RETAIN TO BURNER HEAD
* Drawer assembly not positioned correctly * Move forward or backward
* Nozzle too far forward through centerhole of diffuser * Move nozzle backward respect to diffuser
* Oil or air pressure at nozzle is too low * Increase oil or air pressure
* Air louver too open * Reduce air louver opening
* Too much spread between oil and air (or steam) pressure * Set the spread to a proper value
FLAME IRREGULAR OR SMOKING
* Not enough combustion air * Adjust air flow rate
* Nozzle dirty or damaged * Clean or, if necessary, replace the nozzle
* Flame is too big for furnace or nozzle spray angle is wrong * Check burner-furnace coupling
* Change nozzle with a suitable one
* Nozzle spray angle wrong (flame too long or too wide) * Replace nozzle
* Boiler dirty * Clean the boiler
* Not enough suction at chimney * Check chimney cleanness or size
* Pressure at nozzle too low * Reset oil pressure
* Oil too cold * Reset oil temperature
* Combustion air inlet dirty * Clean the air inlet
* Flame is too small respect to furnace volume * Replace nozzle or reset pump pressure
FUEL GAS TEMPERATURE TOO HIGH
* Boiler dirty * Clean the boiler
* Oil flow rate too high * Adjust oil pressure or replace nozzle