Carrier 48AJ Make Electrical Connections, Field Gas Piping, 48A Series Staged Gas Control

a48-2524

Fig. 18 — Field Gas Piping

IMPORTANT: Natural gas pressure at unit gas connection must not be less than 5 in. wg or greater than 13.5 in. wg.

Size gas-supply piping for 0.5-in. wg maximum pressure drop. Do not use supply pipe smaller than unit gas connection.

OPTIONAL STAGED GAS UNITS — See Table 7 for staged gas information. Staging pattern is selected during controls start-up.

For complete information and service instructions for Staged Gas Control Units, see Control Operation and Trouble- shooting literature.

Table 7 — 48A Series Staged Gas Control

MODEL NUMBER POSITION		NUMBER OF	HEAT SIZE
5	6,7,8	STAGES
	020
	025
	027
	030
S	035		Low
	036
	040	5 stages
	041
	050
	035
	036
T	040		High
	041
	050
	020
T	025	7 stages	High
	027
	030
T	051,060	9 stages	High
S	051,060	11 stages	Low

Step 8 — Make Electrical Connections

POWER WIRING — Units are factory wired for the voltage shown on the unit nameplate.

Provide a unit safety disconnect switch in the main power supply to each unit (see Fig. 19). Select switch size and mount- ing location in accordance with applicable local codes or National Electrical Code (NEC). If combining the functions of safety disconnect with maximum overcurrent protection (MOCP) fuses (“fused disconnect”), coordinate safety switch size with MOCP size data as marked on unit informative plate.

Unit may be equipped with optional factory-installed non- fused disconnect switch (see Fig. 19). Provide maximum overcurrent protection devices (fuses or HACR breakers, per

local codes) in branch circuit wiring remote from unit. Observe requirements of NEC Article 440. Install service switch upstream of remote fuses if required.

The main power terminal block is suitable for use with aluminum or copper wire. See Fig. 19. Units have circuit breakers for compressors, fan motors, and control circuit. The unit must be electrically grounded in accordance with local codes, or in absence of local codes, with NEC, ANSI C1-latest year.

FIELD POWER SUPPLY — Unit is factory wired for volt- age shown on unit nameplate. See Tables 8A and 8B for elec- trical data.

Field wiring can be brought into the unit from bottom (through basepan and roof curb) or through side of unit (corner post next to control box).

A 31/2-in. NPT coupling for field power wiring and a 3/4-in. NPT coupling for 24-v control wiring are provided in basepan. In the side post, there are two 21/2-in. (48A020-035) or 3-in. (48A036-060) knockouts for the field power wiring. See Fig. 4-9. If control wiring is to be brought in through the side of unit, a 7/8-in. diameter hole is provided in the condenser side post next to the control box.

Do not route control wiring in the same conduit as power wiring.

If disconnect box is mounted to corner post, be careful not to drill or screw into the condenser coil.

			TB1
		FIELD	21
	PERDISCONNECTNEC	11
SUPPLIEDFIELD		POWER	22
		12
		SUPPLY	23
		13
		EQUIP GND
		FIELD-INSTALLED DISCONNECT
		OPTIONAL
		FACTORY-INSTALLED
		DISCONNECT
WIRING		11	21
		12	22
POWERFIELD
		13	23
		GND
		FACTORY-INSTALLED DISCONNECT	a48-6977

LEGEND

GND — Ground

NEC — National Electrical Code

TB — Terminal Block

Fig. 19 — Field Power Wiring Connections

20