Carrier NP034-074 specifications Field Control Thermostat Wiring

CONTROL WIRING Ð Install a Carrier-approved acces- sory 24-v thermostat assembly according to the installation instructions shipped with the accessory. Locate thermostat assembly to sense average temperature. Route thermostat cable or equivalent leads of colored wire from subbase terminals to terminal board (P1). The terminal board (P1) is located on the constant volume control board on units with no econo- mizer and on the economizer board on units with the econo- mizer option.

Total wire lengths should not exceed the following limits: 50 ft of 18 AWG, 80 ft of 16 AWG or 125 ft of 14 AWG. See Fig. 19 for ®eld wiring connections between the thermostat and the unit 24-v terminal block. Once wire length from unit to thermostat is determined, the length should be doubled to obtain total wire length required. Voltage drop is dependent on length of current path.

There are no required 115-v ®eld wiring connections, there- fore no provisions have been made in the unit for running 115-v wiring. If any of the ®eld-installed options requiring 115-v connections are desired, the unit must be modi®ed in the ®eld for 115-v wiring.

Options requiring 24-v or 115-v control wiring are listed below.

Building Pressurization or Smoke Purge Mode Ð Refer to appropriate unit Controls and Troubleshooting literature as necessary for additional information. See Fig. 20 and unit wiring label for wiring details.

1.Firestat or smoke detector (®eld-supplied normally- closed switch 1) Ð Remove factory-installed jumper wire and wire a ®eld-supplied ®restat or smoke detector con- tactor between terminals 5 and 6 (034-044 units) or ter- minals 2 and 3 (054-074 units) on terminal block 2 in the unit control box.

2.Switch to drive economizer outdoor-air damper fully open (®eld-supplied normally-open switch 2) Ð Wire a ®eld- supplied switch between terminals 8 and 9 on econo- mizer motor no. 1. When this switch is manually closed, it will drive the outdoor-air damper fully open.

3.Switch to disconnect power to economizer motors (®eld- supplied normally-closed switch 3) Ð Wire a ®eld- supplied switch between terminal C on the economizer motor and Plug 8, Pin 2 (PL8-2).

4.Building pressurization switch (®eld-supplied normally- open switch 4) Ð Wire a ®eld-supplied switch between

Fig. 19 Ð Field Control Thermostat Wiring

TB2 and the C1 connection on the evaporator-fan con- tactor coil (IFC on unit label diagram).

5.Switch to isolate evaporator-fan motor (®eld-supplied normally-closed switch 5).

Modulating Power Exhaust Ð Wire a ®eld-supplied switch in series with the black wire removed from TRAN3 primary.

Constant Volume Power Exhaust Ð Wire a field-supplied switch in series with the black wire from Plug 7, Pin 1 (PL7-1) to the red wire on economizer motor no. 2 (DMS1 on unit label diagram).

6.Switch to energize power exhaust motor (®eld-supplied normally-open switch 6) Ð Wire a ®eld-supplied switch from terminal 5 (on 034-044 units) or terminal 2 (054- 074 units) on terminal block 2 in series with the red wire from switch 5 to the damper motor switch (DMS1) on economizer motor no. 2 (or in parallel with SW5).

7.Switch to fully open power exhaust damper (®eld- supplied normally-open switch 7) Ð Wire a ®eld- supplied switch between terminal C and the normally- closed switch on DPS2.

NOTES AND LEGEND FOR FIG. 20

BUILDING PRESSURIZATION	SMOKE PURGE	ALARM
Switch 1	Switch 1	Switch 1
Switch 2	Switch 2	Switch 3
Switch 4	Switch 5
Switch 5	Switch 6
	Switch 7 (MPE)

Switch 1	Ð Remove jumper. Firestat or smoke detector Ð
Switch 2	Ð	normally closed.
		Switch to drive economizer outdoor-air damper fully
Switch 3	Ð	open Ð normally open.
		Switch to disconnect power to economizer motors.
		Drives economizer outdoor-air damper fully closed Ð
Switch 4	Ð	normally closed.
		Building pressurization switch (energize evaporator-
Switch 5	Ð	fan motor) Ð normally open.
		Switch to isolate evaporator-fan motor Ð normally
Switch 6	Ð	closed.
		Switch to energize power exhaust motors Ð normally
		open.
Switch 7	Ð Switch to fully open power exhaust damper Ð
		normally open.

LEGEND

CÐ Contactor

DPS	Ð Differential Pressure Switch
DMS	Ð Damper Motor Switch
ECON Ð Economizer
IFC	Ð Indoor (Evaporator) Fan Contactor
MPE	Ð Modulating Power Exhaust
NC	Ð Normally Closed
NO	Ð Normally Open
PEC	Ð Power Exhaust Contactor Coil
PL	Ð Plug
SW	Ð Switch
TB	Ð Terminal Block
TRAN	Ð Transformer

NOTES:

1.Power exhaust option can be unit mounted on vertical supply/ return units only.

2. is ®eld wiring.

3.is ®eld wiring.

4.Switches 1-7 are ®eld supplied.

5.For building pressurization, ®eld supplied power source must drive room terminals wide open.

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