Carrier 50LJ User Manual

HEATING & COOLING

48LJ, 50LJ/LW024 Single-Package Cooling Units

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Installation, Start-Up and Service

Instructions

SAFETY CONSIDERATIONS

Installation and servicing of air conditioning equipment can be hazardous due to system pressure and electrical compo­ nents. Only trained and qualified service personnel should install, repair or service air conditioning equipment.

Untrained personnel can perform basic maintenance func­ tions of cleaning coils and filters and replacing filters. All other operations should be performed by trained service per­ sonnel. When working on air conditioning equipment, ob­ serve precautions in the literature, tags and labels attached to the unit, and the other safety precautions that may apply.

Follow all safety codes, including ANSI Z223.1-1984. Wear safety glasses and work gloves. Use quenching cloth for unbrazing operations. Have fire extinguisher available for all brazing operations.

A WARNING

Before performing service or maintenance operations on unit, turn off main power switch to unit. Electrical shock could cause personnel injury.

FOR YOUR SAFETY

WHAT TO DO IF YOU SMELL GAS

Do not try to light any appliance. Do not touch any electrical switch; do not use any phone in your build­ ing. Immediately call your gas supplier from a neigh­ bor’s phone. Follow the gas supplier’s instructions. If you cannot reach your gas supplier, call the fire department.

FOR YOUR SAFETY

Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this or any other appliance.

A WARNING

Improper installation, adjustments, alteration, service or maintenance can cause injury or property damage. Refer to this manual. For assistance or additional in­ formation, consult a qualified installer, service agency or the gas supplier.

A CAUTION

Disconnect gas piping from unit when leak testing at pressures greater than 0.5 psig. Pressures greater than 0.5 psig will cause gas valve damage resulting in a hazardous condition. If gas valve is subjected to pres­ sure greater than 0.5 psig, it must be replaced. When

pressure testing field-supplied gas piping at pressures of 0.5 psig or less, the unit connected to such piping must be isolated by manually closing the gas valve.

Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obiigations.

Book|1 |1	PC 111 Catalog No. 564-937 Printed in U S A Form 48/50LJ,LW-2SI Pg 1	2-92 Replaces; 4/50LJ,LW-1 SI
Tab la 1b

CONTENTS

		Page			Page
	SAFETY CONSIDERATIONS ..............................	1	Return-Air Filters ................................................		22
	INSTALLATION	2-21	Economizer Inlet Screens ..................................		22
			Economizer Dampers and Potentiometer
	Rigging and Unit Placement	2
			Settings		22
	Roof Curb	2
			Operating Sequences		23
	Roof Mount	2
			Ventilation Air Circulation
	............................................................Slab Mount	2	(Continuous Fan)		24
	Alternate Unit Support Methods	2
			Automatic Changeover Using Automatic
	............................................................Positioning	2	Changeover Thermostat		24
	Field-Fabricated Ductwork	3
			Head Pressure Control		24
	Condensate Drain	8
			SERVICE
	Outdoor-Air Inlet Adjustments ..........................	8			24-37
	Install Outdoor-Air Hoods ..................................	12	Service Access ....................................................		24
	Field Wiring Routing ...........................................	14	Cleaning ...............................................................		26
	Field Electrical Connections .............................	15	Lubrication ...........................................................		26
	Gas Piping ...........................................................	21	Adjustments ........................................................		26
	Installing Flue/lnlet Hoods .................................	21	Refrigerant Feed Components ..........................		29
	START-UP	21-24	Acutrol™ Refrigerant Metering Device .............		29
			Filter Drier		29
	Unit Preparation	21
			Protective Devices		29
	Internal Wiring	21
			Relief Devices		30
	Refrigerant Service Ports	21
			Control Circuit,	115-V	30
	Crankcase Heaters	21
			Control Circuit,	24-V	30
	Compressor Oil	21
			Gas Heat		30
	Unit Voltage	21
			Electric Heat		32
	Leak Test and Dehydration	21
			Control Board Checkout		32
	Evaporator Fan, Belt and Sheaves ...................	22
	Condenser Fans and Motors .............................	22

INSTALLATION

This book contains instructions for 48/50LJ vertical supply/ return units and 50LW horizontal supply/retum units.

IMPORTANT: These units are not designed for han­ dling by forklift trucks.

Rigging and Unit Placement — Inspect unit for trans­ portation damage. File claim with transportation agency. Do not drop unit; keep upright. Use spreader bars over unit to prevent sling or cable damage. Rollers may be used to move unit across a roof. Level by using unit frame as ref­ erence. See Fig. 1 for additional information. Unit physical data is shown in Tables la and lb.

Roof Curb — Assemble and install as described in instructions shipped with this accessory. Accessory roof curb and information required to field fabricate a roof curb is shown in Fig. 2a and 2b. Install insulation cant strips, roof­ ing and counter flashing as required. For unit drains to func­ tion properly, curb must be level or within tolerances shown in Fig. 3.

Roof Mount — Check building codes for weight distri­ bution requirements. Unit weight is shown in Tables la and lb.

Slab Mount — Provide a level concrete slab that ex­ tends beyond unit cabinet at least 6 Inches. Make a slab 8-in. thick with 4 in. above grade. (For condensate drain to

function properly, slab must be at least 4 in. above grade. See Fig. 4.) Use gravel apron in front of condenser air inlet to prevent grass and foliage from obstructing airflow.

Alternate Unit Support Methods Where the pre­ ferred curb or slab mount cannot be used, support unit with sleepers on perimeter, using curb support area. However, if sleepers cannot be used, support long sides of unit (see Fig. 5a — 5c) with three 4-in. x 4-in. pads equally spaced. Unit may sag if supported by comers only.

Positioning — Provide clearance around and above unit for airflow, safety, and service access. Allow 12 ft above the unit, and at least 4 ft on all sides for rated performance and code compliance. If unit has economizer, allow 6 ft clearance on that side. For preferred service access, allow 6 ft clearance on all sides.

Do not install unit in an indoor location. Do not locate air inlets near exhaust vents or other sources of contami­ nated air.

Although unit is weatherproof, guard against water from higher level runoff and overhangs.

IMPORTANT: Always line up the condenser end of the unit tight against the roof curb.

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NOTES:

1Rig with 4 cables and spread with two 95-in. (2413-mm) and 2 “A” long suitable spreader bars.

2Center of gravity and unit weight include economizer, but not econ­ omizer hood

A CAUTION

1 All panels must be in place when rigging.

2. Unit is not designed for handling by forklift truck.

NOTICE TO RIGGERS

3/4 IN (19 MM) NOTCHES IN END OF SPREADERS

MODEL	UNIT WEIGHT		A			B			C
	Lb	Kg	In.	mm	In.		mm	In.	mm
48LJD	2895	1313	8591	2182	61		1549	43	1092
49LJE	2975	1349	85.91	2182	61		1549	43	1092
50LJ	2565	1164	6.14	1680	49		1245	44	1118
50LW	2775	1259	85.91	2182	61		1549	43	1092

ACCESSORY/OPTION WEIGHTS

ECONOMIZER

ECONOMIZER

POWER EXHAUST/

ROOF CURB

BAROMETRIC

WITHOUT HOOD

HOOD

RELIEF HOOD

Lb

Kg

Lb

Kg

Lb

Kg

Lb

Kg

280

127

140

63.6

155

70.3

130

59.1

Fig. 1 — Rigging Labei

Field-Fabricated Ductwork — Secure all ducts to building structure, using flexible duct connectors between roofcurb and ducts as required. Ducts passing through an unconditioned space must be insulated and covered with a vapor barrier. Outlet grilles must not lie directly below unit discharge.

48LJ UNITS — These units are field-convertible with the use of an accessory horizontal conversion kit. They are shipped from the factory as vertical supply/retum, but may be field converted to horizontal supply/retum.

Attach field-fabricated ductwork to the roof curb. The retum-air duct connection (inside dimensions) is 46.75-in. long X 30.59-in. wide; the supply-air duct connection (in­ side dimensions) is 38.63-in. long x 27-in. wide. Connect ductwork to 16-gage roof curb material. Secure all ducts to the building structure, using flexible duct connectors be­ tween roof curb and ducts as required. Ducts passing through an unconditioned space must be insulated and covered with a vapor barrier. Outlet grilles must not lie directly below unit discharge. The return duct must have a 90-degree el­ bow before opening into the occupied building space if unit is equipped with power exhaust.

Vertical discharge ducts are designed to be attached to accessory roof curb. If unit is mounted on dunnage, it is recommended that the ducts be supported by cross braces as shown for accessory roof curb. Duct should be the same size as shown on the roof curb certified drawing.

Units may be connected to horizontal supply/retum ductwork with the use of the accessory horizontal conver­ sion package.

50LJ UNITS — On these units, attach field-fabricated ductwork to roof curb. The retum-air duct connection (inside dimensions) is 49.81-in. long x 30.59-in. wide; the supply-air duct connection (inside dimensions) is 37.87-in. long X 31.02-in. wide. Connect ductwork to 16-gage roof curb material. (See installation instractions shipped with accessory roof curb.)

50LW UNITS — On these units, attach field-fabricated ductwork to factory-supplied duct flanges mounted on the side of the unit. See Fig. 5c. Duct flange height is approx­ imately one inch; flange is 18-gage sheet metal. The hori­ zontal supply and return duct openings (inside dimensions) are 26.85-in. wide x 42.03-in. high.

Table 1a — Physical Data, 48LJ Units

BASE UNIT 48LJ	D024		E024
NOMINAL CAPACITY (tons) lb	20		20
OPERATING WEIGHT (lb)*	2895		2975
COMPRESSORS (2 each unit)		Hermetric,	3600 Rpm
Capacity Steps (%)		50, 100
REFRIGERANT	R-22 Controlled by Acutrol™ Metering Device
Operating Charge (lb), Sys 1/Sys 2		16 0/16.0
CONDENSER COILS	3-Row, %-in. Tube Diameter
Face Area (sq ft)		24.75
Fins Per In. (Al)		17.0
EVAPORATOR COILS	4-Row, %-in. Tube Diameter
Face Area (sq ft)		20.3
Fins Per In.		15
FURNACE SECTION	5		10
Number of Heat Exchangers
Input (MBtuh)	242		475
Output (MBtuh)	194		380
Temperature Rise (°F)	10-40		30-60
Burner Orifice Diameter (in. ...drill no.)	.129...30		.129 ..30
Pilot Orifice Diameter (in. ...drill no.)	.046...56		.055...54
Firing Stages	2		2
Number of Gas Valves	1		2
CONDENSER FANS (2 each unit)	Propelier Type, 30-in.		Diameter, 1130 Rpm
Nominal Cfm		13,000
Nominal Hp		1 0
EVAPORATOR FANS (1 each unit)t	Centrifugai Type, 18 x 15-in., 1.438-in. Fan Pulley Bore
Nominal Cfm		8,000
Maximum Allowable Cfm		10,000
Maximum Allowable Rpm		1,200
Standard Motor and Drive		1750 Rpm
Motor Hp		5
Full Load Efficiency (%)		84.3
Motor Frame Size		184T
Fan Pulley Pitch Diameter (in.)		10.6
Motor Pulley Pitch Diameter (in.)		4.75
Resulting Fan Rpm		780
Optional Motor and Drive		1750 Rpm
Motor Hp		7.5
Full Load Efficiency (%)		84.8
Motor Frame Size		213T
Fan Pulley Pitch Diameter (In.)		8.0
Motor Pulley Pitch Diameter (in.)		4.12
Resulting Fan Rpm		900
Optional Power Exhaust	Propeller Type, 1140 Rpm
Motors...Hp		1.. 1.0
Fans...Diameter (in.)		1 .24
Filters (Quantity...L x W xD)		2. 18 X 24 X 2
20% Standard Efficiency Disposable
		4...24 X 24 X 2

'Weights include economizer, but not rainhood. See Fig. 1 for weights of options and accessories.

tStandard fan motor is supplied with standard fan drive and belts Optional motor is supplied with optional fan drive, pulleys, and belts. Other combinations are field supplied.

Table 1b — Physical Data, 50LJ/LW Units

BASE UNIT 50	LJ024		LW024
NOMINAL CAPACITY (tons)	20		20
OPERATING WEIGHT (lb)*	2565		2775
COMPRESSORS (2 each unit)		Hermetric,	3600 Rpm
Capacity Steps (%)		50, 100
REFRIGERANT	R-22 Controlled by Acutrol™ Metering Device
Operating Charge (lb), Sys 1/Sys 2		16.0/16.0
CONDENSER COILS	3-Row, %-in. Tube Diameter
Face Area (sq ft)		24.75
Fins Per In. (Al)		17.0
EVAPORATOR COILS	4-Row, %-in. Tube Diameter
Face Area (sq ft)		20.3
Fins Per In.		15
CONDENSER FANS (2 each unit)	Propelier Type, 30-in. Diameter, 1140 Rpm
Nominal Cfm		13,000
Nominal Hp		1.0
EVAPORATOR FANS (1 each unit)t	Centrifugal Type, 18 x 15-in., 1.438 in. Fan Pulley Bore
Nominal Cfm		8,000
Maximum Allowable Cfm		10,000
Maximum Allowable Rpm		1,200
Standard Motor and Drive		1750 Rpm
Motor Hp		5
Full Load Efficiency (%)		84.3
Motor Frame Size		184T
Fan Pulley Pitch Diameter (in.)		10.6
Motor Pulley Pitch Diameter (in.)		4.75
Resulting Fan Rpm		780
Optional Motor and Drive		1750 Rpm
Motor Hp		7.5
Full Load Efficiency (%)		84.8
Motor Frame Size		213T
Fan Pulley Pitch Diameter (in.)		80
Motor Pulley Pitch Diameter (in.)		4.12
Resulting Fan Rpm		900
Optional Power Exhaust**	Propeller TyiDe, 1140 Rpm
Motors...Hp	1. 1
Fans...Diameter (in.)	1...24
Filters (Quantity...L x W xD)		2...18 X 24 X 2
20% Standard Efficiency Disposable
		4 ..24 X 24 X 2

'Weights include economizer, but not rainhood. See Fig 1 for weights of options and accessories.

tStandard fan motor is supplied with standard fan drive, pulleys and belts Optional fan motor is supplied with op­ tional fan drive, pulleys, and belts Other combinations are field supplied.

"Optional unit-mounted power exhaust not available on Model 50LW. Accessory power exhaust may be duct mounted on 50LW installation

NOTES:

1.Roofcurb accessory 50DJ900401 is shipped disassembled.

2.Dimensions in ( ) are in millimeters.

3 Roofcurb: 16 gage steel.

4.A 90 degree return duct elbow shall be provided for vertical

Fig. 2a — Roof Curb Details, 48LJ/50LW024 Units

NOTES:

1.Roofcurb accessory 50DJ900391 is shipped disassembled.

2.Dimensions in ( ) are in millimeters.

3Roofcurb: 16 gage steel.

4A 90 degree return duct elbow shall be provided for vertical return units equipped with power exhaust

5.A 90 degree supply duct elbow shall be provided for units

equipped with electric heat

NOTE: To prevent the hazard of stagnant water build-up in the drain pan of the evaporator section, unit can only be pitched as shown. See Table 1 for allowable B tolerances.

			DIMENSIONS (degrees and In.)
UNIT	B				C			D
	Deg		In.*	Deg		In.*	Deg		In.*
48U	1 38		4.00
50LJ	1.00		3.25	.50		.75	.50		.75
50LW	1.38		4.00

'From edge of unit to horizontal

Fig. 3 — Unit Leveling Tolerances

Condensate Drain — See Fig. 5a - 5c for drain location. A drain assembly consisting of a 10-gage plate with PA in. half coupling welded to it is shipped inside the base unit, taped to the basepan in the filter section. Open the access panel marked FILTER SECTION and fine drain assembly and the 4 screws required to mount it in the lefthand comer. After unit has been set in place on the roof, remove drain assembly and attach it to the bottom of the unit base rail using the screws provided. See Fig. 4. Use a trap at least 4-in. deep and protect against freeze-up.

On slab mount applications, and when mounted on sleepers, seal hole in bottom of base rail and attach drain assembly as low as possible to side of base rail.

NOTE: Drain hole must be drilled in rail. There is no factorysupplied drain hole in the side of the base rail.

Outdoor-Air Inlet Adjustments

ECONOMIZER SETTINGS

Enthalpy Sensor (Fig. 61 — This sensor is located on the partition separating the outdoor air from the return air. See Fig. 7. The enthalpy setting adjustment is on the top of the economizer motor. See Fig. 8. For maximum benefit of out­ door air, set enthalpy control to the A setting. See Fig. 8 and 9.

Mixed-Air Thermistor — The mixed-air thermistor (MAT) set point adjustment is on the top of the economizer motor. This motor is located in the retum-air section, and is accessed by opening the access panel marked FILTER SECTION. See Fig. 8. Set MAT set point adjustment dial to the desired setting. The factory setting is 55 F ± 5° F; the range is 40 to 90 F. The MAT is located on the filter rack.

Minimum Damper Position Set Point — The minimum po­ sition adjustment is located on the cover of the economizer motor. See Fig. 8. Adjust by setting the fan switch to ON position (continuous fan operation), and setting the system selector switch to OFF position. Then turn adjustment screw slowly until the dampers assume the desired vent position. Do not manually operate the damper motor, damage to the motor my result.

BOTTOM OF BASE RAIL

Fig. 4 — Condensate Drain Piping Details

UNIT SIZE	WEIGHT*		A			B				C		D		E			F			G
	Lb	Kg	mm		Ft-in.	mm		Ft-in.	mm	Ft-in.	mm	Ft-in.	mm		Ft-in.	mm		Ft-in.	mm	Ft-in.
48LJD024	2895	1313.0	1813		6-1%	2182		7-1%	682	2-2%	3909	12-9%	534		1-9	2187		7-2%4	807	2-7%
48LJE024	2975	1349.4	1813		6-1%	2182		7-1%	682	2-2%	3909	12-9%	534		1-9	2187		7-2%4	807	2-7%
‘See note 9.
NOTES:		are in miilimeters
1 Dimensions in [

2. Center of gravity.

3 Ailow 12'-0" [3658] at top and 6'-0" [1829] on sides for service and operationai clearance.

4.On multiunit applications allow 12'-0" [3658] between adjacent condens­ ers and economizers.

5.For smaller service and operational clearances, contact Carrier Appli­ cation Engineering Department.

6.Vertical discharge ducts are designed to be attached to accessory roof curb. If unit is mounted on dunnage, it is recommended the ducts be

supported by cross braces as done on the accessory roof curb.

7Always line up condenser end of unit tight against the roof curb.

8.Units with power exhaust require a 90 degree elbow in return air duct.

9.Weight of unit includes optional economizer. For unit without econo­

mizer, deduct 130 lb (59 Kg).

/—CONTROL BOX ACCESS DOOR

POWER IN (SIDE). (SEE VIEW A)

0'-7 13/16:

[199]

0'-3/4' [13] NPT LOW VOLTASE 0'-3 1/2' [89] NPT FIELD POWER

0'-5 13/16' [146]

UNIT SIZE

WEIGHr

A

B

C

D

E

F

Lb

Kg

mm

Ft-ln.

mm

Ft-in

mm

Ft-in.

mm

Ft-in.

mm

Ft-in

mm

Ft-in.

50LJ024

2565

1163.5

1556

5-1V4

1680

5-6V8

3141

10-3'Vi 6

526

1-8"/i6

807

2-7%

2048

6-8%

*See note 10

NOTES:

1.Dimensions in [ ] are in miiiimeters. Center of gravity.

3.Allow 12'-0" [3658] at top and 6'-0" [1829] on sides for service and operational clearance

4.On multiunit applications aliow 12'-0" [3658] between adjacent condensers and economizers

5.For smaller service and operational clearances, contact Carrier Application Engineering Department

6.Vertical discharge ducts are designed to be attached to accessory roof curb If unit is mounted on dunnage, it is recommended the ducts be supported by cross braces as done on the accessory roof curb

7Always line up condenser end of unit tight against the roof curb.

8Units with power exhaust require a 90 degree elbow in return-air duct.

9.Units with electric heat require a 90 degree elbow in supply-air duct.

10 Weight of unit includes optional economizer For unit without economizer, deduct 130 lb (59 Kg)

Fig. 5b — Base Unit Dimensions, 50LJ024 Units

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UNIT SIZE

WEIGHr

\

B

C

D

E

Lb

Kg

mm

Ft-in

mm

Ft-in.

mm

Ft-in.

mm

Ft-in.

mm

Ft-in.

50LW024

2775

1258 7

1803

5-11

2182

7-1%

682

2-2%

3909

12-9%

534

1-9

*See note 10

NOTES:

1.Dimensions in [ ] are in miiiimeters.

2® Center of gravity.

3Allow 12'-0" [3658] at top and 6'-0" [1829] on sides for service and operational clearance.

4On multiunit applications allow 12'-0" [3658] between adjacent condensers and economizers.

5.For smaller service and operational clearances, contact Carrier Application Engineering Department

6.Always line up condenser end of unit tight against the roof curb.

7.Weight of unit includes optional economizer. For unit without economizer, deduct 130 lb (59 Kg)

	-CONTROL BOX ACCESS DOOR
POWER IN (SIDE:	ELECTRIC HEAT CONTROL
(SEE VIEW A)	BOX ACCESS PANEL
0'-7 13/161	-ACCESS PANEL
[193]

0'-3/4' [19] NPT LOW VOLTAGE 0'-3 1/2' [89] NPT FIELD POWER

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Fig. 5c - Base Unit Dimensions, 50LW024 Units

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Fig. 6 — Enthalpy Sensor

ENTHALPY SENSOR

Fig. 7 — Enthalpy Sensor Location

■CONNECTOR

-ENTHALPY

-MINIMUM

POSITION (CLOCKWISE TO INCREASE)

Fig. 8 - Enthalpy Sensor Setting, Mixed Air

Thermistor (MAT) and Economizer Minimum

Position Adjustments (Top of Economizer Motor)

Fig. 9 — Setting "A" Operating Conditions

Install Outdoor-Air Hoods

ECONOMIZER HOODS — These hoods are shipped sep­ arately from the base unit in a carton. This carton contains;

3 preassembled economizer hoods

1 filter angle

3 filter retainers

6 aluminum mesh cleanable filters, 16 in. x 20 in. x 2 in.

2 channel panels "I pj	cross-section
1 channel clip J	®

1 fastener package (taped to a hood)

The fastener package contains;

8 capscrew bolts, V4—20 x '/2-in. long

8 nuts, '/4—20

18 screws, V4 AB x ys-in. long

8.3 ft of '/8-in. thick X '/2-in. wide seal strip with pressuresensitive adhesive on one side.

1.Remove the lag screws holding the economizer hoods and channel panels to the shipping skid. (There are 4 lag screws per side.)

2.Remove the lag screws holding the filter angle and chan­ nel clip to the shipping skid. (There are 2 lag screws per part.)

3.The filters are wrapped to prevent shipping damage. Remove the screws holding the filter retainers to the hoods. (There are 4 screws per retainer.)

4.Remove wrap from filters. Do not reinstall until after the hoods are mounted to the unit.

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