Bryant 580G manual Enthalpy Control and Sensor

HH57AC077

ENTHALPY CONTROL

C7400A1004	HH57AC078
	ENTHALPY SENSOR (USED WITH
+
	ENTHALPY CONTROL FOR DIFFER-
	ENTIAL ENTHALPY OPERATION)

Fig. 26 Ð Enthalpy Control and Sensor

3.Mount the outdoor air enthalpy sensor inside the right economizer hood on the right side panel of the hood, adjacent to the outdoor-air thermistor.

4.Locate the red, violet, and brown wires near the out- door air thermistor. Remove the splice from the red and violet wires. Remove the cap from the brown wire.

5.Install a 1¤4-in. push on terminal (®eld-supplied) on the violet and brown wires.

6.Connect a 1¤4-in. push on terminal (®eld-provided) to one end of a 18-gage, 6-in. jumper wire (®eld-provided). Con- nect the other end to the red wire and attach a 1¤4-in. push on connector (®eld-provided).

7.Connect the red wire with the jumper to terminal TR1. Connect the jumper to terminal 2. Connect the brown wire to terminal TR. Connect the violet wire to termi- nal 3. All connections are on the enthalpy control.

8.Replace the economizer ®lters.

9.Return power to unit.

Accessory Differential Enthalpy Control (Fig. 26)

The control (HH57AC077), in conjunction with the accessory enthalpy sensor (HH57AC078), controls economizer opera- tion according to the differential enthalpy. The control is mounted in the economizer hood. The sensor is mounted in the return duct (580G) or the return air plenum (580H).

Differential Enthalpy Sensor Installation

To install the control, perform the following procedure:

1.Turn off all power. Ensure disconnect is locked out.

2.Remove the economizer inlet ®lters from the bottom of the right hand economizer hood.

3.Remove the factory-installed, 620-ohm jumper be- tween terminals SR and + on the enthalpy control located inside the outdoor air hood.

4.Connect the violet wire from the enthalpy sensor kit to the + terminal on the enthalpy control. Connect the blue wire from the enthalpy sensor kit to the SR terminal

on the terminal control.

NOTE: Switches shown in high enthalpy state. Termi- nals 2 and 3 close on enthalpy decrease.

Fig. 27 Ð Wire Connections for Solid-State

Enthalpy Control (HH57AC077)

CONTROL CONTROL POINT

CURVE (APPROX. DEG.)

AT 50% RH

A73 (23)

B70 (21)

C67 (19)

D63 (17)

RH Ð Relative Humidity

Fig. 28 Ð Psychrometric Chart for Enthalpy Control

5.Turn the enthalpy control set point potentiometer clock- wise past the ``D'' setting on the enthalpy control to con- ®gure the control to operate on differential enthalpy.

6.Remove the return-air enthalpy sensor from the acces- sory package. Using the screws provided, mount the sensor inside the return duct near the unit. Do not locate the control too far from the unit, or the wires will not reach from the sensor to the control. On 580H units, the enthalpy sensor can be installed in the return air section of the unit, under the return air dampers.

7.Route the wires from the enthalpy sensor to the return air enthalpy control through the holes on the inside of the hinged ®lter access panel. The holes are blocked by plug buttons which should be removed.

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