ICM Controls ICM2911 User manual

LIAF300
ICM2 9 11
Direct Spark Ignition (DSI) control board
Features
Direct Spark Ignition (DSI) control board
Microprocessor-based
 Monitorssystemtiming,trialforignition,systemswitches,amesensingand
lockout
100% lockout safety feature monitors for repeated over-temperature faults or
amelossesanddisablestheheatoperationforsafety.
Continuously monitors the gas valve output to verify the gas valve does not
turnonoroffincorrectly.
Compatible with LP or Natural Gas
LED indication for status and fault codes to aid in troubleshooting
Twinning feature allows two furnace boards to be controlled with a single
thermostat
Replaces
• Modine Spark Ignition Control 5H79749
ELECTRICAL SHOCK HAZARD! Before installing this unit,
turn off power at the main service panel by removing the fuse or switching
theappropriatecircuitbreakertotheOFFposition.FollowallLocal,Stateand
NationalElectricalCodeswheninstallingthisdevice.
CAUTION! 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.
> > > CAUTION < < <
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 the OFF position or set it to the lowest possible setting.
2. Turn OFF the electrical supply to furnace.
3. Turn OFF the gas supply to furnace.
CAUTION! Failure to turn off gas and electric supplies can result in explosion,
re,deathorpersonalinjury.
4. Remove the furnace blower and control access doors.
5. Disconnectthethermostatwiresandhumidierwires(ifequippedwithahumidier).
6. Disconnectthelinevoltage,blower,electronicaircleanerwires(ifequipped)and
transformer wires.
7. Remove screws and any other fasteners and the old circuit board.
8. Examine the control and the control box for water stains.
9. Makerepairsifanysourcesofwaterleakagearefound.Besuretocheckhumidiers,
evaporator coils and vent systems in the area of the control.
Install New Control
1. Ground yourself. When handling the circuit board; hold it by the edges.
2. Fasten the circuit board with the retaining screws.
3. Connect all line voltage, low voltage and accessory wires.
4.Verifythesequenceofoperation.
Sequence of Operation
When a call for heat is made by connecting the W and R terminals, the control runs through
thefollowingsequencetostartthefurnace:
• Control board ensures pressure switch is initially open
• The draft inducer motor is energized
•Theboardconrmsdraftpressurethroughclosureofthepressureswitch
• Inducer performs a 30-second pre-purge delay
• Following the inducer pre-purge delay, the gas valve & spark ignitor energize
•Gasowsintotheburnersandislitbythesparkigniter
•Theamesensorconrmsthepresenceofame
• The spark ignitor stops sparking and the gas stays on with the burners lit
•Athirty-second(30S)heatblowerpre-heatondelayisenactedtopre-heattheplenum
• Following the 30 second pre-heat delay, the heat blower turns on.
• Loss of the heat call deactivates the gas valve immediately and both the inducer and heat
blowers remain running
• The inducer performs a 60 second post–purge delay upon the loss of the heat call
• The heat blower performs a 90 second post purge following the loss of the heat call
Specifications
Input
• Line Voltage: 120 VAC, 50/60 HZ
• Control Voltage: 18 – 30 VAC, 50/60 HZ
Output
• Heat Blower: 15 FLA/30 LRA @ 120 VAC
• Inducer Fan:½HP,(9.8FLA/58.8LRA)@120VAC
• Gas Valve: 2.3A Pilot Duty @ 24 VAC
Environmental
• Operating Temperature:-40°Fto175°F(-40°Cto80°C),-40°Fto185°F(-40°Cto85°C)
Mechanical
• Dimensions: 6.0”L x 5.0”W x 3.0”D
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.
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.
Electrostatic Discharge (ESD) Precautions
Flame Sense Diagnostics
Flame sensing – Thesystemwillusetheamerecticationmethodofamesensing;
usingaremoteamesensingelementconnectedtopin7oftheP1connector.Theame
sensecircuitrywilloperatecontinuously,providingignitionlockoutincaseameissensed
without the gas valve being energized.
Flame sense check – Thecontrolexpectsnormalametobewithin3-5microampsanda
sensedamesignalof1.1microampsorbelowasaweakame.Ifameissensedduring
the 7 second Ignition activation period, the spark ignitor will de-energized after 2 seconds.
Flame circuit is not sensing a ame signal – Ifthecontroldetectsaamesignalwhen
ameisnotexpected;thecontrolgoesintoa1-hourlockoutwhichengagestheinducer
and heat blowers.
Flame loss lockout – Ifatrialforignitionsucceedsandthentheamesensordetectsno
ameafterwards,thecontrolwillimmediatelyshutoffthegasvalveandactivatethemain
blower. If the pressure switch is still closed, the control will attempt another ignition trial
aftera30-secondpre-purgedelay.Ifameislost5timesinonecallforheat,thecontrol
will go into soft lockout. The inducer will turn off after a 60-second post-purge delay, and the
heat blower will turn off after 90 seconds. The status LED blinks code 7 for the duration of
lockout.
Test Mode Delay Duration (sec)
Inducer Pre-purge 5
Trial for Ignition 7
Blower-On Delay 10
Inducer Post-purge 60
Blower-Off Delay 10
5018419
3. Servicethefurnaceaftertouchingthechassis.Yourbodywillrechargewith
staticelectricityasyoushufe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
the used and new controls in separate; containers before touching ungrounded
objects.
6. ESDdamagecanalsobepreventedbyusinganESDservicekitfeetormove
around, and you must reground yourself.
Field Test Mode
Connecting the C terminal to the Test/Twin terminal and disconnecting it in less than
0.9secondsshallputthecontrolintoeldtestmode.Inthismode,pre-purgeandheat
blower delay times are reduced. Trial for ignition and inducer post-purge times remains
the same.

LIAF300
Twinning Connection
When the twin terminals of 2 controls are wired together, the controls will operate their heat blowers at the same time. Connecting a G call on one control will immediately activate the heat
blower on both controls. Removing the G call will immediately deactivate the heat blower on both controls. When the heat blower turns on during the heat cycle of one unit, the heat blower of
the second unit turns on at the same time.
Twinning Error
A twin communication fault is detected if the 24 VAC supplies to the twins are not in phase with each other, or power is removed from one of the twins. While a Twin Fault exists, the control
doesnotrespondtothermostatcommandsandashes“5”onthestatusLED.Ifatwinfaultoccursduringaheatcycle,bothfurnacesterminatethecallforheatimmediately.Ifatwinfault
occurs during high speed fan or continuous fan, both controls shut blowers off immediately.
Wiring Diagram
24V SEC
PRI
Blower
Chassis
Ground
Heating
Speed
CAP
IDM
C
L1
L2
115 VAC
9-Pin Harness Connector
1 N/C
2 Gas valve 24 VAC COM
3 Limit switch IN
4 Gas valve OUT
5 Pressure switch IN
6 Pressure switch OUT
7 Flame sensor
8 Limit switch OUT
9 Flame sensor/chassis ground (24 VAC Common)
Limit
Switches
(N.C.)
Rollout
Switches
(N.C.)
Rollout
Switches
(N.C.)
33
LIM
IN
8
LIM
OUT
5
PS
IN
6
PS
OUT
2
GV
COM
4
GV
OUT
7
FS
9
GND
NOC
Gas Valve
(N.O.) Flame
Sensor
Probe
N.C.
LEGEND
N.C. Normally Closed
N.O. Normally Open
N/C No Connection
PS Pressure Switch
GND Earth Ground
IDM Inducer Draft Motor
PRI Primary
SEC Secondary
L1 Line 1 (115 VAC)
L2 Line 2 Neutral
CAP Capacitor
GV Gas Valve
FS Flame Sensor
LIM Limit Switch
Spark Electrode
Earth
Ground
Fault Codes, Status Lights and Troubleshooting
Flashes Fault Condition Trouble Shooting
Solid On Normal operation Normal operation
Solid Off Gas valve fault Check gas supply to the furnace is turned on. Check for proper voltage to the gas valve during the cycle, check for shorted or
miswired gas valve, and check harness for any shorts or breaks in the wires.
1Pressure switch stays open continuously Check for obstructed pressure switch tubing or defective pressure switch. Check for oxidation on terminals, broken wires, or
defective inducer motor . Check for proper voltage at the inducer motor input.
2Pressure stays in closed position continu-
ously
Check to see if inducer is constantly running and keeping pressure switch closed, check if voltage is being inadvertently applied
to the pressure switch when it should not be, and check or replace pressure switch.
3Open Limit switch Checkforblockedairow,blockedductwork,defectiverolloutswitches
4Ignition failure Lockout Thenumberofretry’sorrecycleshasexceededthelimitforthecontrol.Cleanorreplacetheamesensor,checkthespark
igniterforproperoperationandgrounding,andcheckthetransformer’scommonisgroundedtoearthground.
5Twining fault Ensurethecommonsofbothfurnace’stransformersaretiedtogetherandtiedtoearthground.Checkthewirebetweenthetwin
terminals of each furnace is good, clean,& tight. Check that each furnace is earth grounded. If twinning persists, reverse the
polarityofthesecondarywiresonthestep-downtransformer(SECandCOMatthetransformer24VAC).
6LimitSwitchLockout Max number of trials for open limit switch reached and unit is in a safety lockout. Check the high temperature limit switch and
rollout switches with a multimeter for proper operation and check the wiring attached to the limit switch circuit for any breaks or
oxidationofterminals.Checkforanyairowobstructions.Replacelimitswitchorrolloutswitchesifdefective.
7Flame loss lockout Maximumnumberoftrialsforameestablishmentreached,unitinlockoutduetonoamesensed.Cleanorreplaceame
sensor assembly and check the earth ground to the furnace.
**Note: Gas valve fault lockout – If the control senses voltage across the gas valve terminals when it is supposed to be deactivated, the control goes into lockout. The status LED
turns off, and the inducer comes on after 15s. If the gas valve fault is cleared, the inducer will turn off immediately, but the status LED will stay off and the control remains in lockout.
The gas valve lockout cannot be cleared by toggling a W call; the control must be power cycled, or wait 1 hour after the gas valve fault clears.