Carrier 48AJ, 48EW, 48EY024-068, 48AW, 48AY020-060, 48EK, 48AK, 48EJ Thermistor Designations

Table 5 — Controls Options and Configurations (Non-Thermostat Applications)

	UNIT CONFIGURATION	DEFAULT COOLING	DEFAULT HEATING
CV or VAV Unit with SPT Sensor		Unoccupied Cooling — 90 F (32 C) (SPT)	Unoccupied Heating — 55 F (13 C) (SPT)
		Occupied Cooling — NA	Occupied Heating — NA
CV Unit with SPT Sensor and Remote		Unoccupied Cooling — 90 F (32 C) (SPT)	Unoccupied Heating — 55 F (13 C) (SPT)
Start/Stop Switch		Occupied Cooling — 78 F (26 C) (SPT)	Occupied Heating — 68 F (20 C) (SPT)
VAV Unit Remote Start/Stop Switch Only		Unoccupied Cooling — 90 F (32 C)(SPT)	Unoccupied Heating — 55 F (13 C) (RAT)
		Occupied Cooling — 55 F (13 C) SPT)	Occupied Heating — 68 F (20 C) (RAT)*
VAV Unit with SPT Sensor and Remote		Unoccupied Cooling — 90 F (32 C) (SPT)	Unoccupied Heating — 55 F (13C) (SPT)
Start/Stop Switch		Occupied Cooling — 55 F (13 C) (SAT)	Occupied Heating — 68 F (20 C) (RAT)*
	LEGEND
CV	— Constant Volume
NA	— Not Available
RAT — Return-Air Temperature
SAT — Supply-Air Temperature
SPT	Space Temperature
VAV	— Variable Air Volume

*With DIP Switch No. 5 configured to OPEN (Occupied Heat Enabled).

NOTE: Space temperature sensor and remote start/stop switch are field-supplied.

STAGED GAS UNIT APPLICATIONS — The rooftop units may be ordered with an optional factory-installed staged gas control system that monitors heating operation of the rooftop unit.

IMPORTANT: An accessory field-supplied Navigator dis- play module is required for all staged gas control units.

Install Supply-Air Thermistors (Staged Gas Units Only) — Supply-air thermistors are a field-installed factory-provided component. Three supply-air thermistors are shipped with staged gas units and are inside the heating section. Thermistor wires must be connected to SGC (staged gas controller) in the heating section. See Table 6 and Fig 24. The supply-air ther- mistors should be located in the supply duct with the following criteria:

•downstream of the heat exchanger cells

•equally spaced as far as possible from the heat exchanger cells

•a duct location where none of the supply air thermistors are within sight of the heat exchanger cells

•a duct location with good mixed supply air portion of the unit.

THERMISTORS — All units are equipped with a supply air thermistor (SAT) located in the supply fan discharge and an outdoor air thermistor (OAT) located in the outdoor air hood. Variable air volume (VAV) units are supplied with a return air thermistor (RAT) located on the return air damper support.

CONSTANT VOLUME APPLICATIONS — The units, as shipped, are operable as stand-alone units, using either a stan- dard (mechanical or electronic) 2-stage heat, 2-stage cool ther- mostat, or with an electronic room sensor and a timeclock to establish unit start and stop times.

With a standard thermostat (programmable is optional), heating and cooling operation is set by space temperature.

With a space sensor and timeclock, the machine will operate at default values unless they are changed using appropriate in- put devices. The space sensor senses space temperature and may be equipped with a timed override feature, which allows unit operation during unoccupied periods.

The space sensors may be used in multiples of 4 or 9 to achieve space temperature averaging. The use of a space sensor also allows the unit to be turned on and off from a remote signal.

		Table 6 — Thermistor Designations
	PIN	FUNCTION AND LOCATION
THERMISTOR	CONNECTION		PART NO.
		Thermistors
	POINT
SAT 1	J8 – 1,2 (SGC)	Supply Air Thermistor (SAT) — Inserted into supply section
		underneath the gas heat section (factory-provided, field-installed)
SAT 2	J8 – 3,4 (SGC)	Supply Air Thermistor (SAT) — Inserted into supply section	HH79NZ016
		underneath the gas heat section (factory-provided, field-installed)
SAT 3	J8 – 5,6 (SGC)	Supply Air Thermistor (SAT) — Inserted into supply section
		underneath the gas heat section (factory-provided, field-installed)

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