Troubleshooting The Gc124 - Buderus Logano GC124 II/SP Installation And Service Instructions Manual

Boiler inspection and maintenance
16.8 Troubleshooting the GC124 II
Equipment required: Wiring diagrams (
Start
Close gas shut-off. Set thermo-
stat (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 shut-off. 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, vent damper clos-
es.
End of troubleshooting
We reserve the right to make any changes due to technical modifications.
Installation and maintenance instructions Gas Boiler Logano GC124 II/SP • Issue 07/2006
Chapter 19, page 80) and voltage detectors for 120 VAC and 24 VAC.
No
• Check electrical power source, low-voltage transformer, thermostat (con-
trol) and wiring. Check that the vent damper is open and the limit switch
is present.
• Check that the vent damper operates and limit switches are present. If
No
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 gas shut-offs are open; check that gas
No
connections and pressures are correct and that pilot orifice is not blocked.
• Check electrical connection between ignition module and pilot burner.
• If the voltage is correct replace gas valve, otherwise replace automatic
ignition module.
• Check ignition wiring and ground for continuity.
No
• Check ignition electrode.
• Check electrical connections between ignition electrode and automatic
ignition module.
• 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 alternating current, closed cur-
rent circuit at the automatic ignition. If there is no voltage, replace auto-
No
matic ignition module.
• Check electrical connection between ignition module 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 electrode.
• If everything is OK replace ignition module.
• Check operation of thermostat (control).
No
• Disconnect 24V connection to gas valve. If gas valve closes, check ther-
mostat and line voltage wiring again.
• If the gas valve does not close, replace gas valve.
Repeat procedure until heating system operates properly.
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