Troubleshooting Guides - Landa VNG4-2000 Operator's Manual

PROBLEM
FLOW & BURNER
SWITCH ON; NO
SPARK, NO PILOT GAS
HAVE SPARK, NO
PILOT GAS FLOW
HAVE PILOT GAS,
NO SPARK
TROUBLESHOOTING - BURNER
POSSIBLE CAUSE
A. No main power
B. Faulty transformer
C. Faulty burner & flow switch
D. Faulty ignition control unit
Main gas supply turned off
A. Defective ignitor/sensor and or its
wiring
B. Faulty ignition control unit
96-610 • LANDA VNG/VLP • REV. 9/05
SOLUTION
With power switch on, open trigger on spray
gun and set your test meter to the 24 volt
scale. Probe terminals 24V and 24V(GND). If
you do not read 24 volts, the problem is not
the ignition system. Perform normal system
checks of main power, transformer, thermostat
and the limit control. If you do read 24 volts at
TH and GND, the problem is in the ignition
system. Check for loose or defective wiring. If
wiring is good, replace the ignition control unit.
Set test meter to 24 volt scale.
1. Be sure main gas valve (gas cock or
selector arm) is turned on.
2. With gas on and system sparking, probe
terminals PV and 24V(GND). If pilot gas does
not flow with 24 volts at these terminals,
replace gas valve.
3. Probe terminals PV and MV/PV. If 24 volts
not present, replace ignition control box.
Set test meter to ohm scale.
1. Disconnect the wire from the IGN terminal
on the ignition control unit.
2. Touch one meter probe to the tip of the
ignitor/sensor rod in the pilot. Touch the other
probe to the quick connect at the other end of
ignitor/sensor wire.
3. If you have continuity from the tip of the
ignitor/sensor rod to the connector and no
spark, replace the ignition control unit.
4. If you do not have continuity through wire
and the ignitor/sensor, check for a loose wire
connection in the wire. Repair as needed.
5. Check to see if spark shorts to burner ring
through a cut in the ignitor wire.
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