Boiler inspection and maintenance
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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
16.8 Troubleshooting the GC124 II
Equipment required: Wiring diagrams (
Î
Chapter 19, page 80) and voltage detectors for 120 VAC and 24 VAC.
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.
•
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.
No
No
No
Open main gas shut-off. Ignition
flame is burning.
•
Check that all manually operated gas shut-offs are open; check that gas
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.
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 electrode.
•
If everything is OK replace ignition module.
No
Heat requirement ended, system
switches off, vent damper clos-
es.
End of troubleshooting
Repeat procedure until heating system operates properly.
•
Check that the vent damper 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
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.
No
Main burner ignites.
•
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-
matic ignition module.
•
Check electrical connection between ignition module 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 line voltage wiring again.
•
If the gas valve does not close, replace gas valve.
