8
Boiler inspection and maintenance
Logano G234X – 6 720 804 886 (2012/08) 27
8.7 Troubleshooting the G234X
Equipment required: Wiring diagrams ( page 30) and voltage
detectors 120 VAC and 24 VAC.
Fig. 39 Troubleshooting the G234X
Start
Close gas valve. Set thermostat
(control) to require heat (vent
damper open).
Switch on power.
Observe ignition sparks in gap
between electrode and sensor
through sight glass.
•
Check electrical power source, low-voltage transformer, thermostat (con-
trol) and wiring. Check that the vent damper (if installed) is open and the
limit switch is present.
No
No
No
Open main gas valve. Ignition
flame is burning.
•
Check that all manually operated baffles are open; check that gas con-
nections and pressures are correct and that ignition gas nozzles are not
blocked.
•
Check electrical connection between automatic ignition and ignition timer
on the gas fitting.
•
If the voltage is correct replace gas fitting, otherwise replace automatic ig-
nition.
No
System operates until the heat
requirement ends.
•
Check ignition wiring and ground for continuity. Note: If the ground is
weak or faulty, the system may switch off at random, even if the heating
system operates correctly when checked.
•
Check that the ignition flame surrounds the electrode and burns evenly
with a bluish flame. If OK replace pilot assembly. You can`t get the
•
If everything is OK replace pilot assembly.
No
Heat requirement ended, system
switches off, flue baffle closes.
End of troubleshooting Repeat procedure until heating system operates properly.
•
On models with vent damper check that it operates and limit switches
are present. If necessary, replace vent damper.
•
Check ignition wiring, ceramic insulator of ignition electrode and ignition
gap, adjust if necessary.
•
Check the ignition cable contact for signs of scorching or kinking.
•
Replace automatic ignition unit.
No
Ignition spark stops as soon as
ignition flame burns.
•
Check ignition wiring and ground for continuity.
•
Check ignition electrode.
•
Check electrical connections between ignition electrode and automatic ig-
nition.
•
Check whether the ceramic insulator in the ignition electrode is broken.
•
Check that the ignition flame surrounds the electrode and burns steadily
with a bluish flame.
•
Adjust ignition flame.
•
If this does not correct the fault, replace the automatic ignition unit.
No
Main burner ignites.
•
Use MV-MV/PV terminals to check 24 V AC, closed current circuit at the
pilot assembly.
If there is no voltage, replace pilot assembly.
•
Check electrical connection between pilot assembly and gas valve.
If OK, replace gas valve.
•
Check operation of thermostat (control).
•
Disconnect 24V connection to gas valve. If gas valve closes, check ther-
mostat and connection line again.
•
If the gas valve does not close, replace gas valve.
•
Check if the fuse in 24 V circuit is still working.
electrode seperatly.
6 720 804 440-52.2T
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