Honeywell W7750A specifications W7750 Controllers

EXCEL 10 W7750A,B,C CONSTANT VOLUME AHU CONTROLLER

Table 9. Field Wiring Reference Table (Honeywell listed as AK#### or equivalent).

	Recommended		Specification
Wire	Minimum Wire		or		Maximum Length ft.
Function	Size AWG (mm2)	Construction	Requirement	Vendor Wire Type	(m)
LONWORKS	22 AWG	Twisted pair solid	Level IV	Honeywell	Refer to LONWORKS Bus
Bus	(0.34 mm2)	conductor, nonshielded	140°F (60°C)	AK3791 (one twisted pair)	Wiring Guidelines for
(Plenum)		or Echelon approved	rating	AK3792 (two twisted pairs)	maximum length
		cable.
LONWORKS	22 AWG	Twisted pair solid	Level IV	Honeywell	Refer to LONWORKS Bus
Bus (Non-	(0.34 mm2)	conductor, nonshielded	140°F (60°C)	AK3781 (one twisted pair)	Wiring Guidelines for
Plenum)		or Echelon approved	rating	AK3782 (two twisted pairs)	maximum length
		cable.
Input	18 to 22 AWG	Multiconductor (usually	140°F (60°C)	Standard thermostat wire	1000 ft. (305m) for 18
Wiring	(1.0 to 0.34 mm2)	five-wire cable bundle).	rating		AWG 200 ft. (61m) for 22
Sensors		For runs >200 ft. (61m)			AWG
Contacts		in noisy EMI areas, use
		shielded cable.
Output	14 AWG (2.0 mm2)	Any pair nonshielded	NEC Class 2	Honeywell	Limited by line-loss
Wiring	18 AWG (1.0 mm2)	(use heavier wire for	140°F (60°C)	AK3702 (18 AWG)	effects on power
Actuators	acceptable for	longer runs).	rating	AK3712 (16 AWG)	consumption. (See Line
Relays	short runs)			AK3754 (14 AWG)	Loss subsection.)
Power	14 AWG (2.0 mm2)	Any pair nonshielded	NEC Class 2	Honeywell	Limited by line-loss
Wiring		(use heavier wire for	140°F (60°C)	AK3754 (14 AWG) twisted	effects on power
		longer runs).	rating	pair AK3909 (14 AWG)	consumption. (See Line
				single conductor	Loss subsection.)

W7750 Controllers

Fig. 27 through 35 illustrate W7750A,B,C Controller wiring for various configurations. Connections to the wall module terminals (2 through 6) and the communications terminals (14 and 15) are made at terminal blocks. Connection for access to the LONWORKS Bus is provided by plugging the connector into the communications jack.

1.STRIP 1/2 IN. (13 MM)	1/2
FROM WIRES TO
BE ATTACHED AT	(13)

ONE TERMINAL.

2.TWIST WIRES TOGETHER WITH PLIERS (A MINIMUM

OF THREE TURNS).

Q38

U3

J2

JUMPER

2

1 TERMINAL 24

3. CUT TWISTED END OF WIRES TO 3/16 IN. (5 MM)

BEFORE INSERTING INTO TERMINAL AND
TIGHTENING SCREW. THEN PULL ON EACH
WIRE IN ALL TERMINALS TO CHECK FOR
GOOD MECHANICAL CONNECTION.	M17207

Fig. 25. Attaching two or more wires at terminal blocks.

The W7750B provides a jumper to select High-Side or Low- Side switching of the digital outputs. Fig. 26 shows the W7750B High-Side/Low-Side selectable switching. (See wiring diagrams, Figs. 30 through 34.)

1J2 IS LOCATED NEAR TERMINAL 24 (COVER REMOVED).

2W7750B IS FACTORY-DELIVERED WITH JUMPER ON HIGH-SIDE

(PINS CLOSEST TO TERMINAL BLOCK). LOW-SIDE PINS ARE TWO

PINS CLOSEST TO Q38. M16418A

Fig. 26. W7750B High-Side/Low-Side selectable switching

and jumper location.

NOTE: If an Excel 10 W7750A,B,C Controller or Zone Manager is not connected to a good earth ground, the controller internal transient protection circuitry is compromised and the function of protecting the controller from noise and power line spikes cannot be fulfilled. This can result in a damaged circuit board and require replacing the controller.

See Table 10 for a description of the W7750A terminals.

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