Installation, Operation & Application Guide
For more information on our complete range of American-made
products – plus wiring diagrams, troubleshooting tips and more, visit
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www.icmcontrols.com
ICM2910
Ignition Control Board
Features
• Direct Spark Ignition (DSI) control board
• Microprocessor-based
• Controls spark ignitor and gas valve
• Monitors timing, trial for ignition, flame sensing and
lockout
• Compatible with LP or natural gas
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.
Safety Considerations
Failure to turn off gas and electric supplies can result in
explosion, fire, death, or personal injury.
! CAUTION !
Use caution when installing and servicing the furnace
to avoid and control electrostatic discharge; ESD can
impact electronic components. These precautions
must be followed to prevent electrostatic discharge
from hand tools and personnel. Following the
precautions will protect the control from ESD by
discharging static electricity buildup to ground.
Electrostatic Discharge (ESD) Precautions
1. Disconnect all power to the furnace. Do not touch the
control or the wiring prior to discharging your body’s
electrostatic charge to ground.
2. To ground yourself, touch your hand and tools to a clean,
metal (unpainted) furnace surface near the control board.
3. Service the furnace after touching the chassis. Your body
will recharge with static electricity as you shuffle your feet
or move around, and you must reground yourself.
4. Reground yourself if you touch ungrounded items.
5. Before handling a new control, reground yourself, this
will protect the control. Store used and new controls in
separate containers before touching ungrounded objects.
6. ESD damage can also be prevented by using an ESD
service kit.
Specifications
• Control Voltage: 102-138 VAC
• Flame Current: 1uA minimum
• Current Draw: 50mA maximum
• Gas Valve: 1.5A@120VAC
• Flame Failure Response Time: 0.8 seconds max
• Operating temperature: -40˚F to 175˚F (-40˚C to 80˚C)
• Pre-purge: 7 seconds
• Inter-purge: 7 seconds
• Trial for Ignition: 15 seconds
• Trials: 3
Replaces
Fenwal: 35-725903-997
When the thermostat initiates a “Call for Heat”, the ICM2910
will perform a hardware check, after the hardware check the
ICM2910 will start a 7 second pre-purge. Once the pre-purge
has ended, the spark source and the gas valve relay are
energized simultaneously for 15 seconds. A flame rectification
circuit confirms the presence of the flame, upon flame
detection; the spark source turns off, while the gas valve
remains open for the duration of the heat call.
If flame is not sensed the control will turn off the spark source
and gas valve and start the 7 second inter-purge before the
next trial for ignition. If flame is not detected after 3 trials for
ignition, the control will enter a hard lockout. To remove the
hard lockout: either the input voltage to the control or the
thermostat’s heat call will have to be recycled.
Mode of Operation
