Cuenod NC12 - Troubleshooting

10/2007 - Art. Nr. 13 017 700B20
Troubleshooting
• Check the following if failure occurs:
- power supply (power and control),
- fuel supply (pressure and valve
opening),
- control components.
If problem persists:
• Check light signals of control unit and
their symbols described in table here
below.
To find out what other information shown
by the unit mean, specific equipment is
available and is suited to the SG 113
and SG 513 units.
Safety components must not be repaired
but replaced by similar items.
Only use
manufacturer spare
parts.
Note:
After each operation:
• Check combustion and all circuits for
possible leaks.
• Perform safety checks.
• Record results in the relevant
documents.

Symbol Fault Cause Corrective action
Burner stops
Nothing happens
Normal gas pressure
Thermostatic chain
Insufficient gas pressure
Misadjusted or faulty gas pressure switch
Foreign body in pressure take-off pipe
Misadjusted or faulty thermostats
Adjust distribution pressure.
Clean filter.
Check or replace gas pressure switch.
Clean pressure take-off pipes.
(without pressurized fluid).
Adjust or replace thermostats.
Burner does not start after thermostatic
closure.
Unit does not signal any fault
Low or no power supply
Faulty control unit
Check source of low or missing voltage.
Change control unit.
Burner starts, when powered up, for a short
time then stops and shows this signal
      -     
Unit voluntarily stopped Reset control unit.
Unit control on
     
Air pressure switch: contact is welded Change pressure switch.
Unit control on
     
     
Air pressure switch: contact does not close
Air pressure switch: contact opens during start
up or operation
Check pressure take-off (foreign body) and
wiring.
Adjust, change pressure switch.
Unit control on
     
Stray light during pre-ignition. Check valve tightness and/or change it.
Unit control on
     
No flame signal at end of safety time
Unsuitable gas flow rate
Faulty flame monitoring circuit
No ignition arc
Ignition electrode(s) short-circuiting
Damaged or faulty ignition cable(s)
Faulty ignition transformer
Control unit
Electromagnetic valves do not open
Mechanical jamming in valves
Adjust gas flow rate.
Check state and position of ionization probe in
relation to mass.
Check state and connections of ionization
circuit (cable and measuring bridge).
Adjust, clean or replace electrodes.
Connect or replace cable(s).
Replace ignition transformer.
Change control unit.
Check wiring between control unit, servomotor
and valves.
Check, change coil.
Change valve;
Unit control on
     
Flame disappears while in operation Check ionization probe circuit.
Check or change control unit.