Carrier 48/50AJ specifications IGC LED Indicators

Table 73 — Staged Gas Heat Control Steps (Configuration→HEAT→ SG.CT→HT.ST = 4)

			RELAY OUTPUT
STAGE	Heat 1	Heat 2	Heat 3	Heat 4	Heat 5	Heat 6	CAPACITY
	MBB-RLY8	MBB-RLY7	SCB-RLY1	SCB-RLY2	SCB-RLY3	SCB-RLY4	%
	IGC1	MGV1	IGC2	MGV2	IGC3	MGV3
0	OFF	OFF	OFF	OFF	OFF	OFF	0
1	ON	OFF	OFF	OFF	OFF	OFF	19
2	ON	ON	OFF	OFF	OFF	OFF	25
3	ON	OFF	OFF	OFF	ON	OFF	38
4	ON	ON	OFF	OFF	ON	OFF	44
5	ON	ON	OFF	OFF	ON	ON	50
6	ON	OFF	ON	OFF	OFF	OFF	57
7	ON	ON	ON	OFF	OFF	OFF	63
8	ON	OFF	ON	OFF	ON	OFF	76
9	ON	OFF	ON	ON	ON	OFF	88
10	ON	ON	ON	ON	ON	OFF	94
11	ON	ON	ON	ON	ON	ON	100

RELOCATE SAT (Supply Air Temperature) SENSOR FOR HEATING IN LINKAGE APPLICATIONS — On CCN in- stallations employing ComfortID™ terminals, the factory SAT location must be changed to a new location downstream of the unit’s heating system. The ComfortID terminal controls read the SAT value for their “proof-of-heat” sequence before termi- nals open to Minimum Heating positions during unit heating sequence.

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 — A field-provided duct-mount tem- perature sensor (Carrier P/N 33ZCSENPAT or equivalent 10 kilo-ohm at 25 C NTC [negative temperature coefficient] sensor) is required. Install the sensor through the side wall of the duct and secure.

Table 74 — IGC LED Indicators

LED INDICATION		ERROR CODE
On		Normal Operation
Off		Hardware Failure
1	Flash	Fan On/Off Delay Modified
2	Flashes	Limit Switch Fault
3	Flashes	Fame Sense Fault
4	Flashes	Five Consecutive Limit Switch Faults
5	Flashes	Ignition Lockout Fault
6	Flashes	Ignition Switch Fault
7	Flashes	Rollout Switch Fault
8	Flashes	Internal Control Fault
9	Flashes	Software Lockout

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.

Re-Using the Factory SAT Sensor — The factory sensor is attached to one of the supply fan housings. Disconnect the sen- sor from the factory harness. Drill a hole insert the sensor through the duct wall and secure 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.

MORNING WARM UP — Morning Warm Up is a period of time that assists CCN linkage in opening up downstream zone dampers for the first heating cycle of a day.

The Morning Warm Up Period is CCN linkage mode “2” and is relayed in the following conditions:

•Temperature Compensated Start Mode is active AND Heat Mode in effect AND LAT is warm enough or is to be ignored due to placement.

•The unit just went into occupied mode and there has been no cooling mode yet and a heat cycle occurs or was in prog- ress when the unit went occupied.

In both cases, if and when the heat mode terminates, a heat cycle has occurred and any subsequent heat cycles will not be treated as a morning warm up period.

TEMPERING MODE — In a vent or cooling mode, the roof- top may encounter a situation where the economizer at mini- mum position is sending 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.

Setting up the System — The relevant set points for Temper- ing are located at the local display under Setpoints:

ITEM	EXPANSION	RANGE	UNITS	CCN	DEFAULT
				POINT
T.PRG	Tempering	–20-80	dF	TEMPPURG	50
	Purge SASP
T.CL	Tempering in	5-75	dF	TEMPCOOL	5
	Cool SASP
T.V.OC	Tempering Vent	–20-80	dF	TEMPVOCC	65
	Occ SASP
T.V.UN	Tempering Vent	–20-80	dF	TEMPVUNC	50
	Unocc. SASP

Operation — First, the unit must be in a vent mode, a low cool mode, or a high cool HVAC mode to be considered for a tem- pering mode. Secondly, the tempering mode is only allowed when the rooftop is configured for staged gas (Configuration →HEAT→HT.CF=3).

If the control is configured for staged gas, the control is in a vent, low cool, or high cool HVAC mode, and the rooftop con- trol is in a situation where the economizer must maintain a minimum position, then the evaporator discharge temperature (EDT) will be monitored. If the EDT falls below a particular trip point then the tempering mode may be called out:

HVAC mode = “Tempering Vent”

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