Troubleshooting The G234X - Buderus Logano G234X Installation And Service Instructions Manual

9.7

Troubleshooting the G234X

Required material:
• Circuit diagrams ( page 32)
• Voltmeter 120 VAC and 24 VAC
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.
Open main gas valve. Ignition
flame is burning.
Ignition spark stops as soon as
ignition flame burns.
Main burner ignites.
System operates until the heat
requirement ends.
Heat requirement ended, system
switches off, flue baffle closes.
End of troubleshooting
Fig. 37 Troubleshooting the G234X
Logano G234X – 6 720 811 233 (2014/05)
No
• 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.
Check if the fuse in 24 V circuit is still working.
•
• On models with vent damper check that it operates and limit switches
No
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.
• Check that all manually operated baffles are open; check that gas con-
No
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.
• Check ignition wiring and ground for continuity.
No
• 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.
• 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.
No
• Check electrical connection between pilot assembly and gas valve.
If OK, replace gas valve.
• Check ignition wiring and ground for continuity. Note: If the ground is
No 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
electrode seperatly.
• If everything is OK replace pilot assembly.
• Check operation of thermostat (control).
No
• 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.
Repeat procedure until heating system operates properly.
Boiler inspection and maintenance
9
6 720 804 440-52.2T
29