Carrier 50TFQ008-012 specifications For Differential

Enthalpy Sensors and Control — The enthalpy control (HH57AC077) is supplied as a field-installed accessory to be used with the economizer damper control option. The outdoor air enthalpy sensor is part of the enthalpy control. The separate field-installed accessory return air enthalpy sensor (HH57AC078) is required for differential enthalpy control.

NOTE: The enthalpy control must be set to the “D” setting for differential enthalpy control to work properly.

The enthalpy control receives the indoor and return enthalpy from the outdoor and return air enthalpy sensors and provides a dry contact switch input to the PremierLink™ controller. Locate the controller in place of an existing econo- mizer controller or near the actuator. The mounting plate may not be needed if existing bracket is used.

A closed contact indicates that outside air is preferred to the return air. An open contact indicates that the economizer should remain at minimum position.

Outdoor Air Enthalpy Sensor/Enthalpy Controller (HH57AC077) — To wire the outdoor air enthalpy sensor, perform the following (see Fig. 17 and 18):

NOTE: The outdoor air sensor can be removed from the back of the enthalpy controller and mounted remotely.

1.Use a 4-conductor, 18 or 20 AWG cable to connect the enthalpy control to the PremierLink controller and power transformer.

2.Connect the following 4 wires from the wire harness located in rooftop unit to the enthalpy controller:

a.Connect the BRN wire to the 24 vac terminal (TR1) on enthalpy control and to pin 1 on 12-pin harness.

b.Connect the RED wire to the 24 vac GND terminal (TR) on enthalpy sensor and to pin 4 on 12-pin harness.

c.Connect the GRAY/ORN wire to J4-2 on Premier- Link controller and to terminal (3) on enthalpy sensor.

d.Connect the GRAY/RED wire to J4-1 on Premier- Link controller and to terminal (2) on enthalpy sensor.

NOTE: If installing in a Carrier rooftop, use the two gray wires provided from the control section to the economizer to connect PremierLink controller to terminals 2 and 3 on enthalpy sensor.

If NOT using Carrier equipment, wires may need to be field supplied and installed.

Return Air Enthalpy Sensor — Mount the return-air enthalpy sensor (HH57AC078) in the return-air duct. The return air sensor is wired to the enthalpy controller (HH57AC077). The outdoor enthalpy changeover set point is set at the controller.

To wire the return air enthalpy sensor, perform the follow- ing (see Fig. 17):

1.Use a 2-conductor, 18 or 20 AWG, twisted pair cable to connect the return air enthalpy sensor to the enthalpy controller.

2.At the enthalpy control remove the factory-installed resistor from the (SR) and (+) terminals.

3.Connect the field-supplied RED wire to (+) spade connector on the return air enthalpy sensor and the (SR+) terminal on the enthalpy controller. Connect the BLK wire to (S) spade connector on the return air enthalpy sensor and the (SR) terminal on the enthalpy controller.

ENTHALPY CONTROLLER			RED				S (OUTDOOR
							+	AIR
			BRN
A B C	TR	TR1			BLK			ENTHALPY
								SENSOR)
D	SO	+			RED
	SR	+					S (RETURN AIR
							+	ENTHALPY
	2	3						SENSOR)
		1		GRAY/ORN
LED						WIRE HARNESS
				GRAY/RED		IN UNIT

NOTES:

1.Remove factory-installed jumper across SR and + before con- necting wires from return air sensor.

2.Switches shown in high outdoor air enthalpy state. Terminals 2 and 3 close on low outdoor air enthalpy relative to indoor air enthalpy.

3.Remove sensor mounted on back of control and locate in out- door airstream.

Fig. 17 — Outdoor and Return Air Sensor Wiring Connections for Differential Enthalpy Control

HH57AC077

ENTHALPY

CONTROL AND

BRACKET OUTDOOR AIR

ENTHALPY

SENSOR

HH57AC078 ENTHALPY
SENSOR (USED WITH
ENTHALPY CONTROL	C7400A1004
FOR DIFFERENTIAL
ENTHALPY OPERATION)	+

MOUNTING PLATE

Fig. 18 — Differential Enthalpy Control,

Sensor and Mounting Plate (33AMKITENT006)

17