Carrier 48PG20-28 specifications Connect pressure gage to manifold pressure tap

Condenser Fans and Motors — Condenser fans and motors are factory set. Refer to Condenser-Fan Adjustment section (page 49) as required.

Return-Air Filters — Check that correct filters are in- stalled in filter tracks (see Table 1). Do not operate unit without return-air filters.

NOTE: For units with 4-in. filter option, units are shipped with standard 2-in. filters. To install 4-in. filters, the filter spacers must be removed.

Outdoor-Air Inlet Screens — Outdoor-air inlet screens must be in place before operating unit.

Gas Heat — Verify gas pressures before turning on heat as follows:

1.Turn off field-supplied manual gas stop, located external to unit.

2.Connect pressure gage to supply gas tap, located on field- supplied manual shutoff valve (see Fig. 14).

3.Connect pressure gage to manifold pressure tap.

4.Turn on field-supplied manual gas stop. Temporarily install the jumper wire between “R” and “W1” on TB2. Set thermostat to HEAT and raise set point until heat comes on.

5.After the unit has run for several minutes, verify the sup- ply gas pressure is between 5.5 in. wg to 13.0 in. wg, and the manifold pressure is 2.95 in. wg on horizontal dis- charge applications and 3.00 on vertical discharge appli- cations. If manifold pressure must be adjusted, refer to Gas Valve Adjustment section.

NOTE: Supply gas pressure must not exceed 13.0 in. wg.

6.Set thermostat to OFF.

7.Remove jumper wire if the unit will be operating under thermostat mode.

8.Return thermostat to desired set point.

Table 5 — Fan Performance — 48PGD20 Vertical Supply/Return Units

AIRFLOW							AVAILABLE EXTERNAL STATIC PRESSURE (in. wg)
			0.2			0.4			0.6			0.8				1.0
(Cfm)
		Rpm		Bhp		Rpm	Bhp		Rpm	Bhp		Rpm	Bhp		Rpm		Bhp
5000		590		1.47		663	1.74		727	2.01		786	2.26		840		2.52
5500		633		1.82		703	2.11		764	2.40		820	2.67	A	872		2.94
6000		677		2.21		744	2.53	A	803	2.84	A	857	3.13		907		3.42
6500		722		2.67	A	786	3.01		842	3.33		894	3.64		942		3.95
7000	A	767		3.17		828	3.53		883	3.88		933	4.21	B	979		4.53
7500		813		3.74		871	4.12		924	4.48	B	972	4.83		1017		5.18
8000		859		4.36		915	4.77	B	966	5.15		1012	5.52		1056		5.88
8500		906		5.05	B	959	5.47	C	1008	5.87	C	1053	6.26	C	1096		6.64
9000	C	952		5.81	C	1004	6.25		1051	6.67		1095	7.07		1136		7.47
AIRFLOW							AVAILABLE EXTERNAL STATIC PRESSURE (in. wg)
			1.2			1.4			1.6			1.8				2.0
(Cfm)
		Rpm		Bhp		Rpm	Bhp		Rpm	Bhp		Rpm	Bhp		Rpm		Bhp
5000		891		2.77		940	3.02		987	3.27		1032	3.52		1076		3.77
5500	A	921		3.21		968	3.48		1014	3.74	B	1057	4.01	B	1099		4.27
6000		954		3.70	B	999	3.99	B	1042	4.27		1084	4.55		1125		4.83
6500		988		4.25		1032	4.55		1073	4.85		1114	5.14		1153		5.44
7000	B	1024		4.85		1066	5.17		1106	5.48	C	1145	5.79		1183		6.10
7500		1060		5.51		1101	5.84	C	1140	6.17		1178	6.50	D	1215		6.82
8000		1098		6.23	C	1138	6.58		1176	6.92	D	1213	7.26		1249		7.60
8500	C	1137		7.01		1175	7.38	D	1212	7.74		1248	8.09		1283		8.45
9000		1176		7.86	D	1214	8.24		1250	8.61		1285	8.99		1319		9.36

LEGEND

Bhp — Brake Horsepower Input to Fan

Boldface indicates field-supplied motor/drive required.

NOTES:

1.Motor drive ranges:

(A)Low Range: 685-939 rpm, 4.26 bhp (208/230 and 460-v), 751-954 rpm, 5.75 bhp (575-v)

(B)Mid-Low Range: 949-1206 rpm, 5.75 bhp

(C)Mid-High Range: 941-1176 rpm, 8.63 bhp

(D)High Range: 1014-1297 rpm, 11.50 bhp

All other rpms require field-supplied motor or drive.

2. See page 36 for general fan performance notes.

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