60
Table 49 — Staged Gas Heat Control Steps (HT.ST = 1)
Table 50 — Staged Gas Heat Control Steps (HT.ST = 3)
Table 51 — IGC LED Indicators
NOTES:
1. There is a 3-second pause between error code displays.
2. If more than one error code exists, all applicable error codes will
be displayed in numerical sequence.
3. Error codes on the IGC will be lost if power to the unit is
interrupted.
RELOCATE SAT FOR HEATING-LINKAGE APPLICA-
TIONS — If Configuration
→
HEAT
→
LAT.M is set to YES,
the supply air temperature thermistor (Temperatures
→
AIR.T
→
SAT) must be relocated downstream of the installed heating
device. This only applies to two-stage gas or electric heating
types (Configuration
→
HEAT
→
HT.CF=1 or 2).
Determine a location in the supply duct that will provide a
fairly uniform airflow. Typically this would be a minimum of
5 equivalent duct diameters downstream of the unit. Also, care
should be taken to avoid placing the thermistor within a direct
line-of-sight of the heating element to avoid radiant effects.
Run a new two-wire conductor cable from the control box
through the low voltage conduit into the space inside the build-
ing and route the cable to the new sensor location.
Installing a New Sensor — Procure a duct-mount temperature
sensor (Carrier P/N 33ZCSENPAT or equivalent 10-kilo-ohm
at 25C NTC [negative temperature coefficient] sensor). Install
the sensor through the side wall of the duct and secure.
Re-Using the Factory SAT Sensor — The factory sensor is
attached to the left-hand side of the supply fan housing. Dis-
connect the sensor from the factory harness. Fabricate a mount-
ing method to insert the sensor through the duct wall and se-
cure in place.
Attach the new conductor cable to the sensor leads and ter-
minate in an appropriate junction box. Connect the opposite
end inside the unit control box at the factory leads from MBB
J8 terminals 11 and 12 (PNK) leads. Secure the unattached
PNK leads from the factory harness to ensure no accidental
contact with other terminals inside the control box.
TEMPERING MODE — In a vent or cooling mode, the
economizer at minimum position may send extremely cold
outside air down the ductwork of the building. Therefore it
may be necessary to bring heat on to counter-effect this low
supply-air temperature. This is referred to as the tempering
mode.
STAGE
RELAY OUTPUT
CAPACITY
%
Heat 1 Heat 2 Heat 3 Heat 4 Heat 5 Heat 6
MBB-RLY8 MBB-RLY7 SCB-RLY1 SCB-RLY2 SCB-RLY3 SCB-RLY4
IGC1 MGV1 IGC2 MGV2 IGC3 MGV3
0OFF OFF OFF OFF OFF OFF 0
1ON OFF OFF OFF OFF OFF 37
2ON ON OFF OFF OFF OFF 50
3ON OFF ON OFF OFF OFF 75
4ON ON ON OFF OFF OFF 87
5ON ON ON ON OFF OFF 100
STAGE
RELAY OUTPUT
CAPACITY
%
Heat 1 Heat 2 Heat 3 Heat 4 Heat 5 Heat 6
MBB-RLY8 MBB-RLY7 SCB-RLY1 SCB-RLY2 SCB-RLY3 SCB-RLY4
IGC1 MGV1 IGC2 MGV2 IGC3 MGV3
0OFF OFF OFF OFF OFF OFF 0
1ON OFF OFF OFF OFF OFF 25
2ON ON OFF OFF OFF OFF 33
3ON OFF ON OFF OFF OFF 50
4ON ON ON OFF OFF OFF 58
5ON ON ON ON OFF OFF 67
6ON OFF ON OFF ON OFF 75
7ON OFF ON ON ON OFF 83
8ON ON ON ON ON OFF 92
9ON ON ON ON ON ON 100
ERROR CODE LED INDICATION
Normal Operation On
Hardware Failure Off
Fan On/Off Delay Modified 1 Flash
Limit Switch Fault 2 Flashes
Fame Sense Fault 3 Flashes
Five Consecutive Limit Switch Faults 4 Flashes
Ignition Lockout Fault 5 Flashes
Ignition Switch Fault 6 Flashes
Rollout Switch Fault 7 Flashes
Internal Control Fault 8 Flashes
Software Lockout 9 Flashes