User Guide

ICM2902 Intermittent Pilot Gas Ignition Control Module
SPECIFICATIONSFEATURES
Control Voltage: Line 24 VAC (18-30 VAC) 50/60 Hz
Anticipator Setting: 0.3A plus valve load @ 24 VAC
Prepurge: 15 seconds
Trial for Ignition: 85 seconds
Lockout: 60 minutes
Flame Failure Response Time: 2 seconds
Status LED: See product label for error codes
Operating Temperature:
• Minimum ambient temperature rating is -40°F (-40°C)
• Maximum ambient rating when used with 2.0A main valve is 165°F (74°C)
Relative Humidity: 0% to 95% non-condensing
• Intermittent Pilot Gas Ignition Control Module
• For use with intermittent pilot boilers, furnaces and other heating
appliances
• Microprocessor-based
• Monitors timing, trial for ignition, ame sensing and lockout
• Remote ame sensing
• 100% lockout safety feature
• Compatible with LP or Natural Gas
• Status LED for fault codes to aid in troubleshooting
SAFETY CONSIDERATIONS
Only trained personnel should install or service heating equipment. When working with heating equipment, be sure to read and understand all precautions in the documentation, on labels,
and on tags that accompany the equipment. Failure to follow all safety guidelines may result in damage to equipment, severe personal injury or death.
REMOVE EXISTING CONTROL
CAUTION! To service control, and prior to disconnection, label all wires. Failure to do so may result in wiring errors that can cause dangerous operation.
1. Turn thermostat to OFF position or set it to the lowest possible setting.
2. Turn OFF electrical supply to furnace/appliance.
3. Turn OFF gas supply to furnace/appliance.
CAUTION! Failure to turn off gas and electric supplies can result in explosion, re, death, or personal injury.
4. Label each wire with the correct terminal designation.
5. Disconnect the power supply and the thermostat lead wires from the existing ignition control.
6. Disconnect the sensing probe lead, the high voltage cable, the pilot valve and main valve leads, and any ground leads from the existing ignition control.
7. Remove screws and any other fasteners, and the old ignition board.
INSTALL NEW CONTROL
1. Mount the new control with metal screws or bolts through the mounting holes of the enclosure.
2. Wire per wiring diagrams on reverse side.
3. Verify the sequence of operation.
NOTE: Do not connect the thermostat wires to the control board until wiring is veried.
Sequence of Operation:
The ignition control module’s operation is divided into two phases: 1) Trial for pilot ignition and 2) Main burner operation
Trial for Pilot Ignition
On a “Call for Heat”, the ignition control module energizes the spark source and the pilot valve relay simultaneously. The pilot valve opens, allowing gas to ow to the pilot burner for the
ignition trial time. The spark lights the pilot ame when pilot gas is present. A ame rectication circuit conrms the presence of the pilot ame, shuts off the spark source, and energizes the
main valve relay.
Main Burner Operation
When the main valve opens, gas ows to the main burner where it is lit by the pilot ame. There is a short ame stabilization period as the main valve opens to allow the pilot ame to
stabilize as the main gas lights. The system is now in the run mode with the presence of the pilot ame continuously monitored by the ame rectication circuit. If the pilot ame goes out,
the ignition control module senses loss of pilot ame and shuts off both the pilot valve relay and the main valve relay. Flow of gas to pilot and main burners stops as the valves close (100%
shutoff).
Failed Trial for Pilot Ignition
The ICM2902 control module provides multiple trials for ignition (TFI). If the pilot is not lit or sensed before the end of the trial for ignition time, the ignition control shuts off the spark and pilot
gas (100% shutoff). There is a 60 minute delay before another TFI is initiated. The pattern of TFI followed by a 60 minute delay continues until the pilot lights and is proved or the “Call for
Heat” ends. The 60 minute delay time can be bypassed by cycling the system thermostat or removing and restoring system power.
INTRODUCTION
The ICM2902 Intermittent Pilot Gas Ignition Control Module provides easy eld replacement of Johnson Controls: G776 (63K2401, 41K8701, 69J3601) ignition controls, Lennox: 30W33
ignition control and Robertshaw: 735L (18G91) or 745 (95H04) ignition controls. The ICM2902 replaces existing ame rectication type, intermittent pilot ignition modules with the following
characteristics:
• Remote ame sensing
• Non-100 percent shutoff, 100 percent shutoff/lockout, or 100 percent shutoff/ continuous retry
• Natural or LP gas
• Shutoff/lockout time: 60 minutes
• Prepurge 15 seconds
REPLACES
Johnson Controls: G776 (63K2401, 41K8701, 69J3601) ignition controls Lennox: 30W33 ignition control Robertshaw: 735L (18G91) or 745 (95H04) ignition controls