31
APPENDIX A - CONTROL MODULE
STEP 3:
Check spark ignition circuit.
Disconnect ignition cable at SPARK terminal on mod-
ule.
WARNING
Electrical shock hazard. Ignition circuit
generates over 10,000 volts. Turn OFF
electrical power supply at service panel before
making electrical connections. Failure to do so
could result in death or serious injury.
!
Energize module and listen for audible sparking
noise. When operating normally, there should be
buzzing noise turns on and off twice per second for
duration of 1–7 seconds, depending on model.
STEP 4:
Verify pilot and main burner lightoff.
Initiate call for heat. Turn thermostat above room
•
temperature. Ignition sequence may be delayed
by thermal purge until boiler water temperature is
below 140°F (60°C)
Watch pilot burner during ignition sequence.
•
— Verify ignition spark continues after pilot is lit.
— Verify pilot lights and spark stops, verify main
burner does not light.
If so, ensure adequate
fl
ame current as follows.
•
— Turn off boiler at circuit breaker or fuse box.
— Clean
fl
ame rod with emery cloth.
— Verify electrical connections are clean and tight.
Replace damaged wire..
— Check for cracked ceramic insulator, which can
cause short to ground, and replace igniter-sensor
if necessary.
— At gas valve, disconnect main valve wire from
MV terminal.
— Turn on power and set thermostat to call for
heat. Pilot should light, main burner will remain
off because main valve actuator is disconnected.
— Check pilot
fl
ame. Verify it is blue, steady and
envelops 3/8 to 1/2 in. [10 to 13 mm] of
fl
ame
rod. See Figure 19 for possible
fl
ame problems
and causes.
— If necessary, adjust pilot
fl
ame by turning pilot
adjustment screw on gas control clockwise to
decrease or counterclockwise to increase pilot
fl
ame. Following adjustment, always replace pilot
adjustment cover screw and tighten
fi
rmly to
assure proper gas control operation. Figure 16,
page 20.
— Set temperature below room set-point to end call
for heat.
Recheck ignition sequence as follows.
•
— Reconnect main valve wire.
— Adjust thermostat above room temperature.
— Verify ignition sequence at burner.
— If spark does not stop after pilot lights, replace
module.
— If main burner does not light or if main burner
lights and system locks out, check module,
ground wire and gas control as described in
troubleshooting table. See Table 7, Page 30.
Figure 19 - Troubleshooting Pilot Flame
Correct Pilot Flame: 3/8 to 1/2 inch in fl ame.
See Figure 16, Page 21.
