UTICA BOILERS MGB-50J Installation, Operation & Maintenance Manual page 27

STEP 3: Check spark ignition circuit.
Disconnect ignition cable at SPARK terminal on module.
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 a buzzing noise
that 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 24 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 19.
— Set temperature below room set-point to end call for
heat.
APPENDIX A - CONTROL MODULE
• Recheck ignition sequence as follows.
Figure 24 - Troubleshooting Pilot Flame
Correct Pilot Flame: 3/8 to 1/2 inch in fl ame.
See Figure 20, Page 21.
27
— 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 6, Page 24.