Thisboardshouldbeinstalledbyaqualiedtechnician
only.Failuretofollowtheseinstructionscouldleadto
propertydamage,personalinjuryordeath.
Disconnectthepowersupplybyturningoffacircuit
breakerorremovingafusebeforeattemptingtoinstall
thisboard.
1.Turnoffthepowersupplytothefurnacebyremovingthefuseor
turningoffthecircuitbreaker.
2.Removethewiresandconnectorsfromtheoldboardoneat
atime.CarefullyconnectthemtotheICM2805Atopreventa
miswire.Removethemountingscrewsandthenremovetheold
controlboard.
3.Placethetemplate(onthebackofthissheet)inthecontrolbox
andsecurewithtape.Moveallwiresoutofthewayandcarefully
drillfour3/16”diameterholesasshownonthetemplate.
Removeanddiscardthetemplate.
4.MounttheICM2805Awiththefuseatthetopbyinsertingthe
standoffsintothemountingholes.
NOTE:Do not ex the ICM2805A circuit board. Apply pressure
only at the standoffs.
5.Disconnectthe6-pinconnectorplug.UsinganAMPextractor
tool#458994-2removethebluewirefromsocketposition#4
andinstallitinposition#1.(seediagramatright).Ifthetoolis
notavailableproceedasfollows:
Cutoffthebluewireatsocketposition#4intheconnector(see
diagramatright),andstriptheinsulationback3/8”.Insertthe
lengthofbluewireprovidedinsocketposition#1,nexttothecut
offbluewire.Reconnectthe6-pinconnectorplug.Connectthe
looseendsofthebluewiresusingthewirenutprovided.Tape
thewirenutconnectionwithelectricaltapesoitcannotloosen.
6.ApplythenewwiringdiagramforG4furnacessuppliedwiththe
ICM2805Atotheinsideofthecabinet.
7.Turnonthepowersupplyandcheckthefurnaceforproper
operation.
G3RC and G4 Furnace Models
ICM2805A 1.Turnoffthepowersupplytothefurnacebyremovingthefuseor
turningoffthecircuitbreaker.
2.Removethewiresandconnectorsfromtheoldboardoneat
atime.CarefullyconnectthemtotheICM2805Atopreventa
miswire.Removethecontrolbracketmountingscrewsfrom
theoutsideofthecabinet(exceptG5RLmodels).Installthe
newcontrolbracketandthenproceedtostep4.Ifthescrews
arenotaccessible,newmountingholesmustbedrilledinthe
existingmountingbracketusingthetemplateonthebackofthis
instructionsheet.
3.Removethescrewsecuringtheoldcontrolboardandthen
removetheoldcontrolboard.Placethetemplate(onthebackof
thissheet)overthemountingbracketandsecurewithtape.Move
allwiresoutofthewayandcarefullydrillfour3/16”diameterholes
asshownonthetemplate.Removeanddiscardthetemplate.
4.MounttheICM2805Awiththefuseatthetopbyinsertingthe
standoffsintothemountingholes.
NOTE:Do not ex the ICM2805A circuit board. Apply pressure
only at the standoffs.
5.ApplythenewwiringdiagramforG5furnacessuppliedwiththe
ICM2805Atotheinsideofthecabinet.
6.Turnonthepowersupplyandcheckthefurnaceforproper
operation.
G5 Furnace Models
1.Turnoffthepowersupplytothefurnacebyremovingthefuseor
turningoffthecircuitbreaker.
2.Removethewiresandconnectorsfromtheoldboardoneat
atime.CarefullyconnectthemtotheICM2805Atopreventa
miswire.
3.Removetheoldboardbycuttingoffthestandoffs.Installthe
ICM2805Ainthesamepositionbysnappingthestandoffsintothe
mountingholes.
NOTE:Do not ex the ICM2805A circuit board. Apply pressure
only at the standoffs.
4.Turnonthepowersupplyandcheckthefurnaceforproper
operation.
G6, M2 & M3 Furnace Models
6-pinwireconnector
Whitewire
Blackwire
Bluewirecut
InsertedBluewire
(provided)
ExistingBluewire
(Previouslycutfromslot4)
Whitewire
Blackwire
ExistingBluewire
(Tobecut&connected
towireprovided)
Cutexistingblue
wirehere
InsertBluewire
(provided)
6-pinwireconnector