Carrier 542E User Manual

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Page 1

installation, operation,

and maintenance instructions

542E

Sizes 024 thru 060

PACKAGED HEAT PUMPS

NOTE TO INSTALLER: Leave these instructions with the

unit after installation.

NOTE: The installation of this unit must conform to the

guidelines presented in these unit Installation Instructions. Read and become familiar with this publication before start ing installation.

INTRODUCTION

Models 542D and 542E Packaged Heat Pumps are fully selfcontained combinatipn heating/cooling units designed for outdoor installation. Model 542E may be installed either on a rooftop or ground-level slab. See Figure 1. Model 542D is used with an accessory roof-mounting curb (P/N 304851-

302) and incorporates a down-discharge/return-air plenum as an integral part of the unit. See Figure 2.

These units are factory-charged with R-22 refrigerant. Installation is simple: connect condensate drain, air ducts,

high- and low-voltage.wiring, and install a field-supplied air filter (except for model 542D which has factory-supplied air filters).

All units can be connected into existing duct systems that

are properly sized and designed to handle an airflow of 350 to 450 ffimin per each 12,000 Btuh of rated unit capacity. See

Table I for indoor airflow requirements.

Accessory UL-listed, field-installed, supplemental electric heat packages are available in a variety of KW and voltage options. These electric resistance heaters mount inside the unit blower compartment.

A full line of rooftop system accessories is available for field installation. These accessories include plenums with facto

ry-supplied air filters (plenum not required with Model 542D), roof-mounting curbs, horizontal and downflow economizers, barometric relief dampers, concentric diffuser boxes, and flexible duct packages. Filter racks with air filters are available for rooftop or ground-level installation.

NOTE: When installing any accessory item, see the Installa tion Instructions packaged with the accessory.

IMPORTANT-READ BEFORE INSTALLING

1. This installation must conform with all applicable local and national codes.

2. The power supply (volts, hertz, and phase) must corres pond to that specified on unit rating plate.

3. The electrical supply provided by your utility must be sufficient to handle the load imposed by this unit.

4. Refer to the 542D or 542E dimensional drawing for loca tions of electrical inlets, condensate drain, duct connec tions, and required clearances before setting unit in

place.

5. Styrofoam shipping blocks located between compressor

and divider panel and between accumulator and divider panel must be removed. A failure to remove these blocks can result in undesirable vibration noises being transmitted into the conditioned space.

& 542D060

Cancels: 40542DP6-A

Figure 1—Model 542E

Figure 2—Model 542D060 Mounted on

Accessory Roof-Mounting Curb

GENERAL

Models 542D and 542E Packaged Heat Pumps have been designed and tested in accordance with ARI Standards 24077 and 270-75, and these units are UL-listed.

This publication contains the following sections:

I. Moving and Setting Unit in Place

II. Condensate and Defrost Disposal HI. Duct Connections IV. Electrical Connections

V. Preparing Unit for Startup VI. Startup and Adjustments

VII. Sequence of Operation

VIII. Care and Maintenance

40542DP16-A

6/1/80

A79110

A79111

BDP Company, Division of Carrier Corp.

Page 2

542E REQUIRED CLEARANCE (Inches)

Top of unit Duct side of unit

Compressor access door access end...........................12

side

..................................

.........................

.........................................

CONTROL ACCESS DOOR

COMPRESSOR ACCESS DOOR

48 Blower access door end 12 End opposite blower

30 Bottom of unit above

anticipated snow level.... 6

______

OUTDOOR FAN

ELECTRIC HEAT HIGH-VOLTAGE INLET WITH MULTIPLE KNOCKOUTS

A79071

542E DIMENSIONS (Inches)

Size

024 & 030 60-3/16 32-3/16

036

60-3/16 32-3/16 24-13/16

c D E F

24-13/16

042, 048, & 060 68-3/16 40-3/16 30-13/16

L M N

Sizes

024 & 030 18-1/8

036

042, 048, & 060

18-1/8

25 1-1/2

1-1/2 15-3/32 12-9/16

15-3/32 12-9/16

1-1/2

20-3/32 15-1/8

21 11-1/2 13-5/16 21 13-3/4 13-5/16 21 16-3/8 17-5/16

14-1/2

28-9/16 14-1/2 28-9/16 37-1/8 2 7/8 18-1/2 34-9/16

G H J

57 57 4-5/8 6-15/16 65 5-1/8

37-1/8 2 7/8 44-1/4

Figure 3—542E Dimensional Drawing

TABLE l-RATiNGS, PERFORMANCE, & RECOMMENDED FILTER SIZES

MODEL

SIZE SERIES

Rated Heating Capacity @ 47°F (Btuh)*

Total Power Consumption (Watts)* COP*

Rated Heating Capacity® 17°F (Btuh)*

Total Power Consumption (Watts)* COP*

024

A A A

030

26,000 30,000

2850 3450 3850

2.7 2.5

13,500 16,000 18,000

2350 2900

1.7 1.6

Rated Cooling Capacity @ 95°F (Btuh)* 25,500 30,000

Total Power Consumption (Watts)* EER 7.6

Rated Indoor Airflow (Ft^/Min)*

3350 3900

7.7 7.5

850 1050 Rated External Statio Pressure (In. wc)* 0.10 0.15 ARI Sound Rating Humbert 19 19 Recommended Minimum Filter Size (Sq ln.)t

Standard-Type Cleanable-or High-Capacity-Type 265

408 504

328

* Rated in accordance with ARI Standard 240-77. t Rated in accordance with ARI Standard 270-75. f Recommended field-supplied filter sizes shown are based on a velocity of 300 ft/min at the rated indoor airflow.

**Two 20 X 20 X 1 air filters are furnished with Model 542D060.

ttTo achieve the performance ratings indicated, the fresh-air and exhaust openings of the plenum section must be sealed airtight, the

fresh-air damper must be insulated, and the plenum section must be supported by a curb around an opening to the indoor airspace.

542E

036

35,000

042

A A

42,000

4600

2.7 2.7 2.8 21,000

3000

3700

1.8 1.7 1.8

35,000

4650

41,000

5150

8.0

1300

0.15

1535

0.15

19 18 18

624 406

737 479

6-7/8

6-15/16

7-1/2

27-7/8 27-7/8

7/8 35-3/16

048

48,000

060 060

A A

58,000

5100 6300

2.7

25,000 31,000

4150 5300

5420

58,00011

6300tt

2.7t-

31,00011

530011

1.7 1.711

47,000 57,000

6100 7600

57,00011

7600-t

7.7 7.5 7.511

1700 2000 200011

0.20

0.20 0.2011 20 20

816 530

960 624

** **

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Figure 4—542D060 Dimensional Drawing

TABLE ll-ELECTRICAL DATA-MODEL 542E-SIZES 024 THRU 042

MODEL

SIZE SERIES

Unit Volts—Phase (60Hz) Operating Voltage Range Total Unit Amps Max Branch Circuit Fuse Size (Amps) Unit Ampacity for Wire Sizing Minimum Wire Size (AWG)*

Maximum Wire Length (Ft)*

J024 J030 J036 1 P036

208-230-1 208-230-1 208-230-1

197-253 197-253

197-253

16.7 22.7 23.9 30 45

20.2 27.5 10 10

115 85

542E

208/230-3 230-1

187-253 207-253 187-253

45 25

14.8

28.7 21.0 50 40

29.2 17.8 34.9 10

12 8 10

80 95 112

B042 1 P042

208/230-3

25.2 107

TABLE lll-ELECTRICAL DATA-MODELS 542E048, 542D060, & 542E060

MODEL

SIZE SERIES

Unit Volts—Phase (60Hz) Operating Voltage Range Total Unit Amps Max Branch Circuit Fuse Size (Amps) Unit Ampacity for Wire Sizing Minimum Wire Size (AWG)*

Maximum Wire Length (Ft)*

B048 P048

230-1

207-253 187-253

31.9 60

38.9 27.1 13.2 49.8 35.6 8

101 100 181 123

542E

A A A

E048 060 P060

208/230-3 460-3 230-1 208/230-3

414-506 207-253

22.4

10.9

45 20 60 10

14 6

* Use only copper wire for field connections to unit. Wire size is based on 60 or 75°C copper conductor at 86°F (30°C) ambient tempera

ture and ampacity shown in table. If other than 60 or 75°C copper conductor is used, if ambient temperature is above 86°F, or if voltage drop of wire exceeds 2% of unit rated voltage, determine wire size from ampacity shown and the National Electrical Code. Wire lengths shown are measured one way along the wire path between unit and service panel for minimum voltage drop.

542E 542D & 542E

187-253 414-506

40.9

30.1 13.7 50 25

8 12

119 229

E060

460-3

15.7

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Page 4

USE SPREADER BARS TO PROTECT UNIT

Figure 5—542E Suggested Rigging

USE SPREADER BARS TO PROTECT UNIT

A79148

I. MOVING AND SETTING UNIT IN PLACE

CAUTION: Use spreader bars when rigging the unit to be

lifted to protect the top and sides. Model 542E must be

rigged for lifting as shown in Figure 5. Model 542D must be rigged for lifting as shown in Figure 6. Use extreme caution to prevent damage when moving the unit. It must remain in an upright position during all rigging and moving opera tions. The unit must be level for proper condensate drainage; therefore, the ground-level pad or accessory roof mounting curb must be level before setting the unit in place. When a field-fabricated support is used instead of the ac cessory curb, ensure that the support is level and properly supports the unit and plenum.

When selecting an installation site, locate the unit on the side opposite the prevailing wind to assure proper operation of the defrost cycle and to avoid snow drifts that could block the outdoor coil. Be sure that the unit is installed at least 6

inches above the highest probable snow level to prevent block age of the outdoor coil and to assure proper drainage of de frosted ice.

A. Rooftop Installation

CAUTION: When installing the unit on a rooftop, be sure that the roof will support the additional weight. Refer to the

Product Data Sheet (PDS) for Models 542D and 542E to obtain total weight and corner weight information.

When installing a Model 542D Downflow Unit or a Model 542E End-discharge Unit with an accessory downflow plenum, the accessory roof-mounting curb must be installed on, and flashed into, the roof before unit installation. The instructions for installing the curb are packaged with the curb.

When installing a Model 542E without downflow plenum, place the unit on a level base that provides proper support. On flat roofs, be sure that the unit is located at least 4 inches

above the highest expected water level on the roof to prevent flooding. Consult local codes for additional installation requirements.

B. Ground-Level Installation

Place the unit on a solid, level concrete pad that is a minimum of 4 inches thick and that extends approximately 2 inches beyond the casing on all four sides of the unit. Do not secure the unit to the pad except when required by local codes.

C. Clearances

The required minimum operating and service clearances are shown in Figures 3 and 4. (Refer to the 542D clearances when installing Model 542E with an accessory downflow plenum.)

Figure 6—542D060 Suggested Rigging

CAUTION: Do not restrict outdoor airflow. An air restric

tion at either the outdoor-air inlet (the entire surface of the outdoor coil) or the fan discharge can be detrimental to com pressor life.

The outdoor fan discharges through the top of the unit. Ensure that the fan discharge does not recirculate to the outdoor coil. Do not locate the unit in either a corner or under a complete overhead obstruction. The minimum clearance under a partial overhang (such as a normal house roof overhang) is 48 inches.

Do not locate the unit where water, ice, or snow from an overhang or roof will damage or flood the unit by falling on the top. Do not locate the unit where grass, shrubs, or other plants will interfere with the airflow either into or out of the unit.

II. CONDENSATE AND DEFROST DISPOSAL NOTE: Ensure that defrost and condensate water disposal

methods comply with local codes, restrictions, and practices. Models 542D and 542E dispose of condensate water through

a 3/4-inch MPT plastic drain fitting. To prevent damage dur ing the shipping and moving of the unit, this fitting and a plastic drain pipe are shipped inside the unit compressor compartment (secured with tape). Locate this fitting and 'nsert the nonthreaded end into the plastic drain pipe. See

Figure 8. Insert the plastic pipe over the drain on the drain pan. The pipe and fitting must lay flat against the base for proper drainage. The residual curvature in the pipe must be

in a horizontal plane.

Install a 3-inch trap at the drain fitting to ensure proper drainage. See Figure 7. Make sxire that the outlet of the trap is at least 2 inches lower than the unit drain pan connection to prevent the pan from overflowing. Prime the trap with water.

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LOW-PRESSURE SERVICE FITTING

ACCUMULATOR

ACCUMULATOR FUSIBLE PLUG

DEFROST THERMOSTAT

METERING DEVICE

REVERSING VALVE ASSEMBLY

HIGH-PRESSURE SERVICE FITTING

CAPACITOR(S) (COMPRESSOR a

FAN MOTOR)

BLOWER MOTOR RELAY

BLOWER MOTOR CAPACITOR

DEFROST

RELAY

DEFROST TIMER

TRANSFORMER

LOW-VOLTAGE TERMINAL BOARD

LOW-VOLTAGE INLET HOLE

CHASSIS GROUND CONNECTION

LOW-PRESSURE SWITCH

INDOOR COIL DRAIN PAN

4 MPT PLASTIC DRAIN FITTING

^(SHIPPED TAPED INSIDE

COMPRESSOR COMPARTMENT)

COMPRESSOR

Figure 8—Partial Side'View With Compressor & Control

Access Panels Removed (Model 542E036, 208V-230V—1)

During the heating defrost cycle, defrost water from the melting ice on the outdoor coil flows through the holes in the heat pump base directly below the outdoor coil. When using a field-supplied drain pan to catch the defrost water, be sure that this pan is at least 2 inches high and extends at least 2 inches beyond the width and length of the unit.

If the installation requires draining the condensate and/or defrost water away from the unit, connect a drain tube(s), using a minimum of 7/8-inch OD copper tubing, 3/4-inch galvanized pipe, or 7/8-inch plastic pipe. Do not undersize the tuhe(s). Pitch the drain tube(s) downward at a slope of at least 1 inch in every 10 feet of horizontal run. Be sure to check the drain tube(s) for leaks.

Condensate and defrost water can be drained directly onto

the roof in rooftop installations (where permitted) or onto a gravel apron in ground-level installations. When using a gravel apron, make sure it slopes away from the unit.

III. DUCT CONNECTIONS

Model 542E has duct flanges on the supply- and return-air openings on the side of the unit. See Figure 3 for connection sizes and locations.

Model 542D has duct flanges on the supply- and return-air openings on the bottom of the unit. See Figure 4 for connec tion sizes and locations.

WARNING: The design and installation of the duct system must be in. accordance with the standards of the National Fire Protection Association for installation of nonresidencetype air conditioning and ventilating systems, NFPA No. 90; or residence-type, NFPA No. 90B; and/or local codes and ordinances.

Adhere to the following criteria when selecting, sizing, and installing the duct system:

1. Select and size ductwork, supply-air registeis, and return-air grilles according to ASHRAE recommenda tions and as presented in BDP training materials.

QUICK-START PTC THERMISTOR

■HIGHVOLTAGE PIGTAIL LEADS

A79243

CAUTION: When the duct system fastening holes are being

drilled into the side of Model 542E instead of the unit duct flanges, use extreme care to avoid puncturing the coil or coil tubes.

2. Use a flexible transition between rigid ductwork and unit to prevent transmission of vibration. The transi tion may be screwed or bolted to duct flanges. Use suita ble gaskets to ensure a weather and airtight seal.

NOTE: When using a supplemental electric heater, main tain a minimum clearance of one inch to combustible materials for the first 36 inches of duct and use fireproof material for the transition between the ductwork and unit supply-air duct flange. When using flexible duct (which is not heat resistant), use a 36-inch long sheet metal duct be tween the supply outlet and the flexible duct. Observe the

warning on the unit rating plate.

3. Install an external, field-supplied air filter(s) in the return-air ductwork where it is easily accessible for ser vice. Recommended filter sizes are shown in Table I. (Model 542D has factory-supplied air filters.)

4. Size all ductwork for required indoor airflow of heat pump being installed. This airflow will be adequate for safe electric heater operation (except when using 20KW heater with 030-size unit airflow must be at least 1000 fU/min). Avoid abrupt duct size increases or decreases.

5. Adequately insulate and weatherproof all ductwork

located outdoors. Insulate ducts passing thru an uncon

ditioned space, and use a vapor barrier in accordance

with the latest issue of SMACNA and NESCA minimum installation standards for heating and air conditioning systems. Secure all ducts to the building structure.

6. Flash, weatherproof, and vibration-isolate all openings

in building structure in accordance with local codes and good building practices.

Page 6

HIGH-VOLTAGE PIGTAIL LEADS

BLK

BLK ^

RED

/ r-Tok F1ELD-SUPPL1E(

3-PHASE UNITS ONLY

-FIELD SPLICE

SWITCH

POWER SUPPLY

A79244

Figure 9—Field High-Voltage Connections

IV. ELECTRICAL CONNECTIONS WARNING: The unit cabinet must have an uninterruptedj

unbroken, electrical ground to minimize the possibility of personal injury if an electrical fault should occur. This ground may consist of electrical wire connected to the unit ground lug in the control compartment, or conduit approved for electrical ground when installed in accordance with the National Electrical Code and local electrical codes. A failure to follow this warning could result in the installer being lia ble for the personal injury of others.

CAUTION: A failure to follow these precautions could result in damage to the unit being installed;

1. Make all electrical connections in accordance with the National Electrical Code and local electrical codes governing such wiring.

2. Use only copper conductor for connections between the field-supplied electrical disconnect switch and the unit. DO NOT USE ALUMINUM WIRE.

3. Ensure that high-voltage power to the unit is within the operating voltage range indicated on the unit rating

plate. On 3-phase units, ensure that phases are balanced within 2%. Consult the local power company for correc tion of improper voltage and/or phase balance.

4. Insulate low-voltage wires for the highest voltage con tained within the conduit when low-voltage control wires are run in the same conduit as high-voltage wires.

5. Do not damage internal components when drilling thru any panel to mount electrical hardware, conduit, etc.

6. Make sure that the service conductors used between the electrical service panel and the field-supplied electrical disconnect switch do not have a current capacity less

than the copper wire specified, and do not create a total voltage drop in excess of 2% of the rated voltage of the unit.

NOTE: When using aluminum conductor from the electrical

service panel (power supply) to the disconnect switch (where local codes permit the use of aluminum wire), make the con nections in accordance with the National Electrical Code. Prepare all aluminum wire immediately before installation by “brush-scratching” the wire, then coating the wire with a corrosion inhibitor (such as Pentrox A). Be sure that the entire connection is completely covered to prevent an electrochemical reaction that will cause the connection to fail very quickly. Do not reduce the effective size of the wire by cutting off strands to fit the wire into a connector. Always use properly sized connectors.

A. High-Voltage Connections

The unit must have a separate electrical service with a fieldsupplied, waterproof fused disconnect switch at, or within sight of, the unit. Refer to the imit rating plate for max imum fuse size and minimum circuit amps (ampacity) for

wire sizing. Tables II and III show recommended wire sizes and lengths based on rating plate data.

The field-supplied disconnect switch box may be mounted on the unit over the high-voltage inlet hole in the control cor ner panel. See Figure 3 or 4. Be sure that the disconnect box does not interfere with the removal of the blower access

panel.

Proceed as follows to complete the high-voltage connections to the unit:

1. Connect ground lead to chassis-ground connection when using a separate ground wire.

2. Connect high-voltage power leads to unit high-voltage pigtail leads. Single-phase units have two black pigtail leads. Three-phase units have two black and one red pig tail lead. See Figure 8, Figure 9, and unit wiring label. Use a suitable wire splice connector or wirenut to make each high-voltage connection. Tape each completed con nection.

B. Special Procedures for 208-V Operation WARNING: Make sure that the power supply to the unit is

switched OFF before making any wiring changes.

When operating sizes 018 thru 036 single-phase units or sizes 036 thru 060 208/230-volt three-phase units at 208 volts, disconnect the red transformer-primary lead from the contactor. See the unit wiring label and Figure 8. Remove the tape and cover from the terminal on the end of the blue transformer-primary lead. Save the cover. Connect the blue lead to the contactor terminal from which the red lead was disconnected.

Using the cover removed from the blue lead, insulate the loose terminal on the red lead. Wrap the cover with electri cal tape so that the metal terminal can not be seen.

NOTE: If a blower motor speed is changed, insulate all

unused motor leads following the same procedures described for the transformer leads.

C. Low-Voltage Connections

The recommended heat pump room thermostats for heat pump operation with or without supplemental electric heaters are P/N 34427DP115 (subbase included) for auto matic system changeover and P/N 34427DP118 (subbase included) for manual system changeover. These thermostats have an emergency heat (EM. HT.) switch and red indicator light.

Heat pump room thermostat P/N 34427DP87 (subbase included) can be used for heat pump operation without sup plemental electric heaters. This thermostat provides for manual system changeover and does not have an emergency heat switch.

NOTE: When a supplemental electric heat package is being used, see the Installation Instructions packaged with the heater to complete system low-voltage wiring connections.

Locate the room thermostat on an inside wall in the space to be conditioned where it will not be subjected to either a cool ing or heating source, or direct exposure to sunlight. Mount the thermostat 4 to 5 feet above the floor.

Use No. 18 AWG color-coded, insulated (35°C minimum) wires to make the low-voltage connections between the ther mostat and the unit. If the thermostat is located more than

100 feet from the unit (as measured along the low-voltage wires), use No. 16 AWG color-coded, insulated (35°C minimum) wires.

A grommeted, low-voltage inlet hole is located in the panel adjacent to the control access panel. See Figure 3 or 4. Run the low-voltage leads from the thermostat, thru the inlet hole, and to the low-voltage terminal board. See Figure 8. Connect the low-voltage thermostat leads to the terminal

-6-

Page 7

Figure 10—Field Low-Voltage Connections Using Room

Thermostat P/N 34427DP115 or P/N 34427DP118

HEAT PUMP LOW-VOLTAGE TERMINAL BOARD

Figure 11—Field Low-Voltage Connections Using Room Thermostat P/N 34427DP87

A79245

АГ9246

board as shown in Figure 10 or 11, depending on which recommended room thermostat is being used.

NOTE: When using thermostat P/N 34427DP115 or

34427DP118, run a thermostat lead from each of the 10 thermostat terminals. Insulate the end of the leads that do

not have a connection point in the unit.

D. Heat Anticipator Settings

The recommended room thermostats have a fixed heat antic ipator for heat pump heating. When using an accessoryelectric heater to provide supplemental heat and emergency heat capability for the system, see the Installation Instruc tions packaged with the heater for setting the adjustable second-stage heat anticipator.

V. PREPARING UNIT FOR STARTUP WARNING/DANGER: A failure to observe the following

warnings could result in serious personal injury:

1. Follow recognized safety practices and wear protective goggles when checking or servicing refrigerant system.

2. Do not operate compressor or provide any electric power to unit unless compressor terminal cover is in place and secured.

3. Do noT remove cdmpro.s.--or terminal cowr uniil all elecrrical sources have bet ;n disconnec red.

4. Relieve all pressure from system before touching or dis turbing anything inside terminal box if a refrigerant

leak is .suspected an)und compressor tcriViinal.s.

0. Do tiot use a torch to remove any coiitporienr. 8\-.41е7П

contains oil and refrigerant under pressure. To remove a component, wear protective goggles and proceed as

follows:

a. 8hur oil' electrical ]io\ver t() unit. b. Relieve all pre.s.suri' t'roui .system. c. Cut component connecting tubing with tubing cut

ter and remove component from unit.

d. Carefully unsweat remaining tubing stubs when

necessary. Oil can ignite when exposed to torch

flame.

A. Prestartup Procedures

Proceed as follows to inspect and prepare the unit for initial startup:

1. Remove all access panels.

2. Remove stryofoam shipping blocks from between com pressor and divider panel, and between accumulator and divider panel

-7-

Page 8

Figure 12—Removing Belt-Drive Blower Shipping Bracket

A80089

3. Read the following instructions on all WARNING, CAUTION, and INFORMATION labels attached to unit; for example, blower rotation labels, etc.

4. Refer to Figure 12 and remove shipping bracket from belt-drive blower units as follows:

a. Locate shipping bracket mounted on blower

housing.

b. Remove two bracket mounting screws from each

side of blower housing.

c. Remove rubber knob and shipping nut from adjust

ing bolt.

d. Discard shipping bracket and nut, then replace rub

ber knob on end of adjusting bolt.

e. See Section VI, part C, to adjust indoor airflow.

5. Make the following inspections:

a. Inspect for shipping and handling damages such as

broken lines, loose parts, disconnected wires, etc.

b. Inspect for oil at all refrigerant tubing connections

and on unit base. Detecting oil generally indicates a refrigerant leak. Leak-test all refrigerant tubing connections, using electronic leak detector, halide torch, or liquid-soap solution. If refrigerant leak is detected, see “Refrigerant Leaks” in the next part of this section.

c. Inspect all field and factory wiring connections. Be

sure that connections are completed and tight.

d. Inspect coil fins. If damaged during shipping and

handling, carefully straighten fins with a fin comb.

6. Verify the following conditions:

a. Make sure that outdoor fan blade is correctly

positioned in fan orifice. Blades should clear motor

by H4 inch.

b. Make sure that air filter (s) is in place.

c. Make sure that condensate drain trap is filled with

water to ensure proper drainage.

d. Make sure that all tools and miscellaneous loose

parts have been removed.

7. Replace all access panels. (Unit is now ready for initial startup.)

B. Refrigerant Leaks

Proceed as follows to repair a refrigerant leak and to charge the unit:

WARNING: Never attempt to repair a soldered connection

while the refrigerant system is under pressure. Severe bodi ly injury may result. Always wear protective goggles when servicing the refrigerant system.

1. Locate leak and ensure that refrigerant system pressure has been relieved.

2. Repair leak, following accepted practices.

NOTE: Install a filter-drier whenever the system has been

opened for repair.

3. Add a small charge of R-22 refrigerant to system and leak-test unit.

4. Evacuate refrigerant system if additional leaks are not found.

5. Charge unit with R-22 refrigerant, using a volumetric charging cylinder or accurate scale. Refer to unit rating

plate for required charge. Be sure to add extra refrigerant to compensate for the internal volume of the filter-drier.

NOTE: See Section VI, part B, for checking and adjusting

refrigerant charge.

VI. STARTUP AND ADJUSTMENTS CAUTION: Complete the required procedures given in Sec

tion V, “Preparing Unit for Startup,” before starting the unit.

Do not jumper any safety devices when operating the unit. Do not operate the compressor until electric power has been

applied to the heat pump for a minimum of 4 hours to ensure that the oif-cycle crankcase heater has sufficiently warmed the compressor oil to free most of the accumulated refrigerant.

Do not rapid-cycle the compressor. Allow 5 minutes between “on” cycles to prevent compressor damage.

A. Checking Unit Operation

Start and check the unit for proper operation as follows:

1. Place room thermostat SYSTEM switch in OFF posi tion. Observe that indoor blower motor starts when FAN switch is placed in ON position and shuts down when FAN switch is placed in AUTO position.

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Page 9

Air Temp at

Indoor Coil

Inlet |°F DB)

TABLE IV-HEATING PERFORMANCE PRESSURES

Pressure

Designation

(Psig)

High Side 250 229

Low Side 69 59

High Side 268

Low Side 70

High Side 280 256 233 211 190 172 155 140 266

Low Side

60 50 40 30 20 10 0

243 220 199 180 162 147 134

60 50 42 34 26 19 15

71 61 51 43 35 27 20 16 73 62 52 43

54ZED24 542E030

Air Temperature at Outdoor Coil

F°DB

-10

209 190 172 155 140 127

49 41 33 25 18 14 71

238 218 201

251 231 211

Air Temperature at Outdoor Coii

60 50 40 30

184 169 155 144 134

50 41 32

72 61

246

195 179

51 42

207 190 176 162 151 261

226

°FDB

10 0 -10

18 13 64 52

165

33 25 19 14 65 53

34 26 20 15

153 142

60 50 40 30 20

232 214 198

247

66 54 48 40 32 26

Air Temperature at Outdoor Coil °FDB

542E036

183 170 158 149 142

46 38 31 25

230 213 198 184 171

243 225

31 25 19 13

209 195 182 171 162

0 -10

161 152

Air Temp at Indoor Coil

Inlet (°FDB|

65 High Side 254

75 High Side

Pressure

Designatiun

IPsig)

Low Side 71 62 50 42 32 24

High Side 268 250 230 205 183 169 156 144

Low Side 72 63 51 43 33 25

Low Side 73

60 50 40 30 20 10

234

283 266 243 218 194 180 166 153

542E042 542E048

Air Temperature at Outdoor Coil °FDB

0 -10

216 193 171 159 148

52 44 34 26 19 14

136

18 14 64

60 50 40

262

278

290 266

65 57 49

66 58

TABLE V-COOLING PERFORMANCE PRESSURES

Air Temp at

Indoor Coil

Inlet (°FWB)

Air Temp at Indoor Coil

Inlet l°FWBI

60 High Side

65 High Side 173 187 201 215 231 246 263 280 298

70 High Side 177 191 205 220 235 251 268 285 303 322 193 208 223 240

75 High Side 181 196 210 225 240 256 273 290 308 327 198 214 229 246

Pressure

Designation

IPsigI

55 High Side 157 174 190 207 224 240

Low Side 58 59 60 61 62 63 64 66 67 68 60 62 63 65

60 High Side

Low Side

65 High Side 168 185 200 216 232 247 264 282 298 317 157 173 188

Low Side 70

70 High Side 173

Low Side 77 78 79 80 81 82 83 84 86 87

75 High Side

Low Side 84 85 86 87 88 90 91 93 94 95

Pressure

Oesignation

High Side

Lew Side

Low Side

Low Side 68 69

Low Side 72 73

Low Side 76 77 79 81

65 70 75 80 85 90 95

195

162 179

64 65 66 67 68 69 70 71

71 72

191

206 223 239 253 270

175 192 209

(Psig)

55 70 75 80 85 90 95 100 105 110 65 70 75 80

165 179 192 206 222

60 62 63 65 67 68 70 72 74 75 61 62 63 65 66 68

169 183 196

64 66 67 69 70 72 74 75 77 79 65 66 67 69 70

71 73 74 76

75 77

542E024

Air Tem p at Outdoor Coil |°F DB|

244

212 228

227 242

260 278

542E042

Air Tem p at Outdoor Coil l°F 08) Air Tem p at Outdoor Coil l°F 08)

237 254

210

241

226

82 84

too

258 276 293 313

261 279 296 315

76 77 78 79 80

258

80 82 83 85 87

105 110 55 70 75

304 324 160 177 192 208

288

294 315

270

275 293 312

336

289 308

317

79 81 83 69 70 71 73

91 77

150 166

153

169

74 63 65 66 68 70 72 75

67 69 70 72 74 76 79 81 83 85 71 73

70 72 74 76 78 80 83 85 87 89 74 76

164

180 196 212 228

74 76 78 80 82 84 87 89 91 93 79 81

178 192

197

183

188 203 218

74 75 77 78 80 82

78 80 81

Air Temperature at Outdoor Coll

20 10 0

237 214 193

48 40

251 226

242 220 201

50 42

Air Tem p at Outdoor Coil (°FDBI

196 212 226 246 264 282 302 182

181

185 200 216 230 250 268 286 306 185 199

204

207 224 238 255 272 291 308 330

212 229

235 249 266 283 302 320 340

174 158

204 184 166

41 34

542E030

85 90 95 100 105 110 55 70

235 255 273

220

224 240 259 277 295

244 264 282 300 320 196 212 228

542E048

85 90 95 100 105 110

243 260

72 74 76 78 80 63

76 78

254 271 288 307 326 345 191

260 277 294 312 332 350 198

83 84 86 88 90 92

"FOB

-10 60 50

144 134 268

33 26 19

27 20 13

184 169

35 28

73 75

70 72 74 76 59 61

277

296 314

80 82 84 67

13 66

154 146

21 14 68

79 81 69

291 311

86 88

284 252

158 298

77 67 69 70 72

188 203 219

192 207 223 239

315

65 70 75 80 85 90

176 189 202

335 180 193

185 198

71 73

196 211 227 242 259 276

65 66 6/ 68 /0

69 70

205 219

212

77 79 80 82

5420060. A 542E060

Air Temperature at Outdoor Coil °FDB

40 30 20 10 0 -10

238 210 186 166

57 48 40 32 25 19 13

268 238 212 190

58 49

75 80 85 90 95 100

215 231 246 263 280 298 316 336

71 72 74 76

74 76 78 80 81 83

77 79 81 83

83 84 86 88 89 91

62 63 65 6/ 68

207 222 237 254 270 287 305

212 227 242 259 275 292 31U

74 /5

227 242 258 274 292 310 328 346

224

198 178

54ZE035

Air Tem p at Outdoor Coii l°F OBI

74 75 76 78 79 81

235 251

255 273 290 308 326 346

244 260 278 296 314 332 352

5420060 S 542E060

Air Tem p at Outdoor Coil (°F0BI

217 233 249 266 283 300 320

234 250 266 283 301 319 338

151 142

32 24 19 13

164 154 146

1/4 162

25 20 14

294 312 332

80 82 83

285 303 321 341

268

95 100 105 110

/0 /2 /4

/1 /3 /5 n

/6 /8 80

80 81 83 85

84 85 8/ 89 91

136

156

105 110

85 86

88 89

93 9b

324

329

2. Place SYSTEM switch in COOL position and FAN switch in AUTO position. Set thermostat cooling control below room temperature to start cooling cycle. Observe that compressor, outdoor fan, and indoor blower motors start. Observe that unit shuts down when control set ting is satisfied. Wait 5 minutes for pressures to equalize.

3. Place SYSTEM switch in HEAT position, and leave FAN switch in AUTO position. Increase thermostat

heating control setting gradually until thermostat

“calls” for heat. Observe that compressor, outdoor fan, and indoor blower motor start. If supplemental electric

heater is being used in the system, increase thermostat heating control setting an additional 6 degrees. Observe that the supplemental electric heater energizes. Set control setting below room temperature, and observe that heater deenergizes and that heat pump shuts down.

4. If supplemental electric heater is being used in the

system, leave FAN switch in AUTO position, SYSTEM switch in HEAT position, and move emergency heat switch from NORM, position to EM. HT. position. Set thermostat control setting above room temperature to

start heating cycle. Observe that all supplemental electric heat is energized, that indoor blower motor starts, that emergency heat indicator bulb lights, and that compressor and outdoor fan do not start. When con trol setting is satisfied, observe that heater deenergizes and that blower motor stops; however, indicator light should remain on as long as emergency heat switch is in

EM. HT. position.

5. If autochangeover thermostat P/N 34427DP115 is being used, place both SYSTEM and FAN switches in AUTO position. Observe that heat pump operates in heating mode when heating control selector is set above room temperature, and operates in cooling mode when cooling control selector is set below room temperature.

B. Checking and Adjusting Refrigerant Charge

The refrigerant system is fully charged with R-22 refrigerant, tested, and factory-sealed. For most applica

tions, the factory charge is the correct amount for the best

performance; however, this charge rnay require a slight

adjustment to attain rated performance.

-9-

Page 10

NOTE: Adjustment of the refrigerant charge is not required

unless the unit is suspected of not having the proper charge. An operating pressure/temperature tag is fastened inside

the compressor compartment. (Also see Tables IV and V.) Use this tag to approximate the charge if ARI rating condi tions can not be obtained, when evaluating the refrigerant charge by checking operating pressures and temperatures. This method of evaluating ensures that an optimum refrigerant charge is in the system when the system condi tions and components are normal; however, adjusting the refrigerant charge does not solve or fix system abnor malities.

The amount of refrigerant charge affects how efficiently and economically the unit operates. An overcharged or under charged unit leads to diminished efficiency, high operating costs, and the possibility of premature compressor failure.

CÀUTION; When evaluating the refrigerant charge, an

indicated adjustment to the specified factory charge must

always be very minimal. If a substantial adjustment is indi

cated, an abnormal condition exists somewhere in the

system; such as insufficient airflow across either coil or both

coils. When checking the refrigerant using the temperature/pres-

sure evaluation method, adhere to the following criteria:

1. Check refrigerant charge in cooling mode when outdoor temperature is above 65°F.

2. Check refrigerant charge in heating mode when outdoor temperature is below 65°F.

3. For best results, do not operate unit continuously for

more than 10 minutes if for any reason charge must be checked in opposite mode above or below 65°F.

Proceed as follows to evaluate the system performance and refrigerant charge:

1. Remove caps from low- and high-pressure service fit

tings. See Figure 8.

2. Attach low- and high-side pressure gauge hoses to lowand high-pressure service fittings, respectively. Hoses

must have valve core depressors. Gauges must be cali

brated for accuracy.

3. Set room thermostat below room temperature to start cooling operation or above room temperature to start

heating operation, depending on outdoor temperature. Allow unit to operate until conditions stabilize and pressures level out.

4. Determine and record these conditions:

a. Low- and high-side pressures. b. Dry-bulb temperature of inlet air at outdoor coil.

c. Temperature of inlet air at return-air grille—creí

bulb if operating in cooling mode or dry bulb if operat ing in heating mode.

5. Evaluate system performance and refrigerant charge by

comparing recorded reading with operating pres sure/temperature tag.

6. Make slight adjustment to refrigerate charge when

necessary.

NOTE: If the problem causing the inaccurate readings is a refrigerant leak, see Section V, part B, of these instructions.

high- and low-speed connection (except for 460-V motors

which have only a high-speed connection).

The system airflow for all direct-drive units (except 460-V)

can be changed, when necessary, by changing the blower motor speed connection from the factory setting to the unused speed connection. The factory setting is indicated on the unit wiring label. For operation of units designed for 208-V and 230-V operation, a blower motor speed connection may need to be changed. See unit wiring label. See Section

IV, part B, for the procedure. Model 542D060 and 542E060 3-phase units have belt-drive

blower motors. The system airflow for these units can be changed, when necessary, by adjusting the blower-motor pulley as follows:

CAUTION: Increasing the hlower speed places a heavier

load on the motor and increases the current. Do not exceed the rated full load amperage indicated on the rating plate of the blower motor.

1. Turn off power at disconnect switch.

2. Relieve belt tension, then remove drive belt from motor pulley.

3. Loosen setscrew in movable flange on motor pulley and turn flange either in to increase airflow or out to decrease

airflow.

4. Make sure that setscrew is over flat surface on pulley

hub and tighten setscrew.

5. Replace belt and adjust belt tension for approximately

one inch of sag under normal finger pressure midway between pulleys.

Tables VI and VII show the air delivery performance at various external static pressues. Determine the airflow for the system being installed as follows;

1. Start the unit and measure static pressure in duct

system at unit.

2. Refer to Table VI or VII and determine airflow at static

pressure measured.

NOTE: Be sure that all supply- and return-air grilles are open, free from obstructions, and adjusted properly.

When using an accessory electric heater, the system airflow

can also be determined by measuring the temperature rise through the unit, then using the following formula:

AIRFLOW (ftVmin) =

where, KW = Heater nominal KW at 240 or 480V TR = Measured temperature rise Y =

200V 208V

2195

NOTE: Value Y varies with the operating voltage at the heater.

Interpolate to determine the value of Y for voltages not shown.

2374 2655

220V 230V 240V 440V 460V

2902

480V 3160

C. Indoor Airflow & Airflow Adjustments CAUTION; The recommended indoor airflow is 350 to 450

ft®/min per each 12,000 Btuh of rated unit capacity. Inade quate airflow can cause unsatisfactory operation and per formance.

Model 542E, sizes 024 thru 048, and single-phase 060-size units have direct-drive blower motors. All motors have a

CAUTION: When using an accessory electric heater, the

system airflow must be sufficient to prevent the heater limit switches from tripping off. W'hen using the 20-KW single phase heater, the system airflow must be at least 1000 ft^/min.

-10-

Page 11

TABLE VI-AIR DELIVERY (FtVMin) AT INDICATED EXTERNAL STATIC PRESSURE & VOLTAGE*

Blower

Model

542E024 Low

542E030

542E036

542E042 Low

542E048

542E060

(Single-

Phase

Units)

* Deduct field-supplied air filter pressure drop & heater loss (when used) to obtain available external static pressure for ducting, t Heating airflow values are with a dry coil. Cooling airflow values are with a wet coil.

NOTE: Shaded portions of this table fall below 350ft^/min per 12,000 Btuh of rated cooling capacity. Indoor coil icing may ocur at airflows

below this point. Dashes are used in those areas of the table that fall beyond the capability of the indoor blower motor.

Motor

Speed

High 208 Heating

Low

High

Low

High 208 Heating 1685

High 208 Heating

Low

High 208 Heating

Low 230 Heating

High 230 Heating 2700

Opera

ting

Voltage

208 230

230 208 230 Heating 208 Heating 230 Heating 208 Heating 230 Heating

230 Heating 208 Heating 230 Heating

230 460 Heating

Applica-

Heating Cooling Heating Cooling

Cooling Heating Cooling Heating Cooling

Cooling

Cooling Cooling Cooling 1225

Cooling Cooling 1565 Cooling Cooling 1370 Cooling Cooling 1825 Cooling 2030 Cooling 1650 Cooling 1860 Cooling

Heating 2270

Cooling 2180 Cooling 2000 Cooling Cooling 2550

tiont

External Static Pressure—Inches wc

0.0 0.1

880 835 850 810

965 925

940 900

1015 970

985 1070 1040

995

980

1070 1055 1165 1150 1260 1245 1280

1485 1400

1850 1670 1400 1360 1315

1655 1615 1895 1840 1780

2125 2065 2005 1690 1635 1575 1905 1855 1800 2005

1955 1905

2070 2000 2250

2180 2135 2085

940 1030 1000

965

945 910 865 820 760 1050 1025 1030 1005

■ 1145 1130 1105 1075 1035

1245 1225 1200 1165 1225 1235 1185 1140 1435 1380 1350 1300 1630 1510 1455 1785 1720 1615 1560

1330 1280 1610 1560 1505 1435 1360 1270 1565 1510 1450 1380 1305 1205 1050

1770 1710 1645 1570 1490 1395 1270 1970 1905 1835 1760 1675 1575 1440 1595 1535 1475 1405 1810 1755

1955 1900 1845 1780 1705

2195 2120 2110 2040 1960 1880

1930 1855 2205 2160 2110 2050 1990

2625 2550 2465 2380 2285 2475 2395 2315 2220 2120 2005

0.2

790 770 880 855 810 920 870 890 840 785 985 940 885 955 910 855 800 930 890 845 785

1125

1200 1170 1185 1135

1575

1850 1790 1725 1650 1560 1430

1925 1845 1760 1665

0.3 0.4 0.5 0.6

740 725 835

995 960 915 970 930 880 800 680

1095 1065 1020 955 845

1095 1325 1265 1250 1190 1510 1395 1325 1250 1160 1650 1575 1495 1425

M265v

1230 : 1165 : ■ 1085 955

1715 1645 1570 1480 1365 1935 1860 1510

1740 1675 1600 1510 1690 1625 1545 1445 1290

2040 1955 1870 1765 1650

1775 1690 1595 1490 1355 2030 1970 1900 1815 1700

690 675 615 550 465 780 720 655 755 815 750 685 605

1135 1080 1005 875 1080 1020 955 875 1040 985 920 850

1440 1360 1275 1160

1:205: 1130 : 1015-

1440

630 565 470

700 635 730 665 585

830 765 680

980

1125

1200 1125 1050 970

1490 1395 1280 1345 1250 1100

1775 1360 1270 : 1140

1325

1785 1685 1570

735 705 680 840 730

900

1065 970

1115

1685 1570

1,230

1625 1510

1560 1915 1830

2175 2055

0.7

575 560

660 590 560

770

1025

1045

■ ■

: 1140

1100

:1370

1425

1860

D. Unit Controls

All compressors have the following internal protection con trols:

1. High-Pressure Relief VaZue—This valve opens when the pressure differential between the low and high side becomes excessive.

2. Compressor Ckterload—This internal overload interrupts power to the compressor windings when either the cur rent or internal temperature become excessive, and au tomatically resets when the internal temperature drops to a safe level. This overload may require up to 60 minutes (or longer) to reset; therefore if the internal overload is suspected of being open, disconnect the electrical power to the unit and check the circuit thru

the overload with an ohmmeter or continuity tester.

3. Low-Pressure Switch—This switch with automatic reset interrupts the compressor control circuit when the

refrigerant high-side pressure becomes too low. It pro tects the compressor from damage attributable to loss of the refrigerant charge.

4. TimelTemperature Defrost System—The defrost control system consists of a defrost timer, a defrost thermostat switch, and a defrost relay. The system initiates defrost cycle operation every 90 minutes if a coil icing condition exists. See the defrost cycle sequence of operation in Section VII.

5. Crankcase Heater—This device prevents overdilution of compressor oil with refrigerant during shutdown

, periods, thereby extending the life of the compressor.

See the crankcase heater sequence of operation in Sec tion VII.

6. Compressor Quick-Start Components—These components are used with all single-phase units to improve com pressor starting characteristics.

-11-

Page 12

TABLE VII-MODEL 542D060 & 542E060-

3-PHASE UNITS-MOTOR PULLEY SETTINGS

FOR AIR DELIVERY AT INDICATED EXTERNAL

SP & VOLTAGE WITH WET COIL

{ 208 Volts—Standard Motor Pulley & Belt |

Airflow

(Ft3/Min)

1750 1875 — — 5 2000 - - 4-1/2 3-1/2 2-1/2 2 2125 — 5 2250

1 230 Volts—Standard Motor Pulley & Belt )

Airflow

(Ft3/Min)

1750 1875 — — 2000 2125 5 4-1/2 4 2250 4-1/2 4

1 460 Volts—Standard

Airflow

(Ff3/Min)

1750 —

1875 2000 2125 2250

1 208 Volts—Optional Motor Pulley & Belt {

Airflow

(Ff3/Min)

1600 5 4 1650 1700 1750 3-1/2 1800 3-1/2

1 230 Volts—Optional Motor Pulley & Belt |

Airflow

(Ft3/Min)

16ÜÖ 5

1650 4-1/2 3-1/2 3 2 2 1-1/2 1 1700 4 1750 1800 3-1/2

1 460

Airflow

(Ff3/Min)

1600 1650 1700 3-1/2 1750 1800 3-1/2 2-1/2 2 1-1/2 1 1/2 0

1 208 Volts-Standard Motor Pu ley & Be

Airflow

(Ff3/Min)

1750 1875 5 2000 2125

2250

Airflow

(Ff3/Min)

1750 — 5 1875 5 4 3 2 1-1/2 2000

2125 3 2 2250

1 460 Volts—Standard Motor Pulley & Beit |

Airflow

(Ff3/Min)

1750 —

1875 5 2000 2125 3 2250

542E060 STANDARD DRIVE RANGE

0.30

T.O.

— —

—

4-1/2

0.40 0.45 0.50

T.O. T.O. T.O.

— —

— 5

0.30 0.40 0.50 0.60 0.70

T.O. T.O. T.O.

— — — — —

—

0.50 0.60 0.70 0.80

0.40

T.O. T.O. T.O. T.O. T.O.

— 4-1/2 3-1/2

3-1/2 2-1/2 1-1/2 1/2

— 5 —

4-1/2 4 3-1/2 3 3

4 3-1/2

—

— 5 3-1/2 3

—

4-1/2

0.55 0.60 0.65 0.70

T.O. T.O. T.O. T.O.

4-1/2 4 3-1/2 3

3-1/2 3-1/2

Victor Pulley & Belt |

TO.

4 4

3-1/2

2 1

4-1/2 4 3-1/2

T.O.

3 3 2 2 1

542E060 OPTIONAL DRIVE RANGE

0.20 0.25 0.30 0.35 0.40 0.45

T.O.

4-1/2 3-1/2 3 2 1-1/2

0.20 0.25 0.30 0.35 0.40

T.O.

T.O. T.O.

Volts—Optional Motor Pulley & Beit |

0.20 0.25

T.O. T.O. T.O. T.O. T.O. T.O. T.O.

3-1/2 3 2-1/2 2 1-1/2 1

3-1/2

T.O. T.O.

T.O.

2-1/2

3 3

4 3

2-1/2 2 1-1/2 1 1/2

2-1/2 2 1-1/2 1

2-1/2 2 1-1/2 1 1/2

2-1/2 2 1 1 1/2

2-1/2

2-1/2 2 1-1/2 1 1/2

2 1-1/2 1 1/2 0

2-1/2 2 1-1/2 1

2 2 1 1 1/2

0.30 0.35 0.40 0.45 0.50

2 1-1/2

T.O.

542D060 STANDARD DRIVE RANGE

0.10 0.20 0.30 0.40 0.50 0.60 0.70

T.O. T.O. T.O.

—

2-1/2 2 1 1/2 0

0.10 0.20 0.30 0.40

T.O. T.O. T.O. T.O. T.O.

0.10

T.O. T.O.

4-1/2

3-1/2

4 3-1/2 3 2 1-1/2 1/2 0 2-1/2

1-1/2 1-1/2

0.30 0.40 0.50 0.60

0.20

T.O. T.O. T.O. T.O. T.O.

3-1/2 2-1/2 1-1/2 1 1/2

1-1/2 1 0

1-1/2 1/2 0

T.O.

2 1 1

1/2

1/2 0 —

— — —

230 Volts—Standard Motor Pulley & Belt |

3 2-1/2 1-1/2 1

2 1-1/2 1

3-1/2

2-1/2 2 1 1/2

■t 1

T.O. T.O.

2 1-1/2 1

0,50

2-1/2 1-1/2 1

—

0.90

T.O. 2-1/2 2 2-1/2 1

2-1/2 2

0.80 0.90

T.O. T.O.

1-1/2 1/2

T.O. T.O. 1-1/2 1 1-1/2 1

0.45 0.50

T.O. T.O.

—

0.60 0.70

T.O.

2-1/2

2 1-1/2 2

0.50

1 1/2

1/2

T.O.

0 —

T.O.

1 0

—

0.70

— — -

1/2 —

—

— —

— — —

—

NOTES:

1. Values shown for Model 542E'are without air filter. Values shown for Model 542D are with faotory-supplied 1-inch air filters. Use values shown for Model 542D when using the accessory field-installed down flow plenium with Model 542E.

2. T.O. = Blower motor pulley turns open.

3. Dashes indicate portions of thè table that are beyond the drive range.

4. Optional drive for Model 542E060: motor pulley P/N 50611B6 & belt P/N 94006

5. Motor pulley factory setting is two turns open.

7. Outdoor Fan Thermostat—This control, which is featured on all 3-phase units, maintains the proper cooling mode condensing temperature by switching the outdoor fan motor to high- or low-speed operation. Low-

speed fan operation permits low-ambient cooling opera tion down to 40°F outdoor temperature.

VII. SEQUENCE OF OPERATION

Do not leave the installation until the heat pump has been

observed throughout one or two complete cycles. The installer should make certain during this time that all com ponents are operating in correct sequence.

The sequences of operation described in this section pertain

.to size 036, 042, and 048 208/230-volt, 3-phase units;

however, the sequence of operation of all units is very simi lar. Refer to the line-to-line wiring diagram in Figure 13.

NOTE: Although the actual unit wiring may vary slightly

from that shown in Figure 13, the sequence of operation will not be affected. The sequences of operation described in this

section pertain to a typical system using room thermostat

P/N 34427DP115 or P/N 34427DP118 for system control, and using an accessory electric resistance heater for supple mental heat.

NOTE; The indoor blower motor will operate continuously,

regardless of the room thermostat SYSTEM switch position, when the FAN switch is in the ON position. The ON position of the FAN switch keeps the circuit through blower relay coil 2A closed and the coil energized. When the FAN switch is in the AUTO position, the blower operates only when the system is started by the room thermostat demand for heat ing or cooling.

A. Crankcase Heater Operation

Compressor crankcase heater llA is connected across nor mally open cmpressor contactor 2D contacts between 13 and

23. When electric power is supplied to the heat pump, and the unit is not operating in either the heating or cooling mode, a completed circuit between power legs LI and L3 per mits current to flow through one leg of compressor motor 3F windings and through crankcase heater 11 A. The high electrical resistance of the crankcase heater causes the heater to heat up, while the compressor motor windings serve only as a means of completing the circuit between LI and L3.

When the heat pump receives a “call” for either heating or cooling, normally open compressor contactor 2D contacts between 13 and 23 close. (See heating and cooling sequences of operation in this section.) Electric current, which always follows the path of least resistance, flows through the closed contacts and through both compressor motor 3F and outdoor fan motor 3D1. The crankcase heater, which offers a much higher electrical resistance than the two motors, receives virtually no electrical current as long as the contactor is energized.

-12-

Page 13

B. Cooling Operation

With the room thermostat SYSTEM switch in the COOL position and the FAN switch in the AUTO position, the cool ing sequence of operation is as follows:

When the room temperature rises to within 2 degrees of the cooling control setting of room thermostat, the thermostat cooling operation bulb tilts and connects thermostat ter minal R to thermostat terminal O. This completed circuit through the thermostat completes the circuit through unit terminal O. Reversing valve solenoid coil 5B and outdoor fan relay coil 2C are now connected across the 24-volt secondary of unit transformer IB.

Energized solenoid coil 5B switches the reversing valve from the normal heating mode position to the cooling mode posi tion. Energized outdoor fan relay coil 2C closes its set of nor mally open contacts between 1 and 3, and opens its set of

normally closed contacts between 1 and 2, permitting two-

speed outdoor fan motor 3D1 to operate on either high or low

speed, depending on the outdoor ambient temperature.

NOTE: When the contacts of outdoor fan relay 2C are in

their normal heating mode positions as shown in Figure 13, fan motor 3D1 operates on high speed, regardless of the out door ambient temperature.

The heat pump is now in the “standby” condition and ready to operate in the cooling mode when the room thermostat “calls” for cooling.

When the room temperature rises to a point that is slightly above the cooling control setting of the thermostat, the ther mostat cooling bulb tilts and thermostat terminal R is auto matically connected to thermostat terminals G and Y. These completed circuits through the thermostat connect indoor blower relay coil 2A (through unit terminal G) and com pressor contactor coil 2D (through unit terminal Y) across the 24-volt secondary of transformer IB.

The set of normally open contacts of energized relay 2A be tween 1 and 3 closes and completes the circuit through

indoor hlower motor 3D2. The motor starts instantly.

The two sets of normally open contacts of energized contac tor 2D between 13 and 23, and 11 and 21, close and complete the circuit through compressor motor 3F and outdoor fan motor 3D1. Both motors start instantly. The current flow through outdoor fan motor 3D1 also flows through fan switching thermostat 7K, which maintains the optimum cooling mode condensing temperature by switching the fan motor to high- or low-speed operation, depending on the out

door ambient temperature. The heat pump is now operating in the cooling mode. The

energized reversing valve is directing the high-temperature, high-pressure discharge gas to the outdoor coil, where the heat is transferred to the outdoor air.

All three energized motors continue to run and the cooling

cycle remains “on” until the room temperature drops to a

point that is slightly below the cooling control setting of the room thermostat. At this point, the thermostat cooling bulb tilts and breaks the circuit between thermostat R to ter minals G and Y. These open circuits deenergize indoor blower relay coil 2A and compressor contactor coil 2D. All closed contacts return to their normally open position, and all three motors stop.

The heat pump has now returned to a “standby” condition, awaiting another “call” for cooling hy the room thermostat. If the room temperature continues to fall, the thermostat cooling operation bulb will tilt and break the circuit be

tween thermostat terminals R and 0. This open circuit deenergizes reversing valve solenoid coil 5B and outdoor fan relay coil 2C. The fan relay contacts open, and the reversing valve switches to the normal heating mode position.

Except for the crankcase heater, all heat pump components are now deenergized. When the room temperature rises again and reaches the room thermostat control points, the cooling sequence will start again. If the room temperature continues to drop, the heat pump will remain “ofT’, and the heating mode will not start until the room thermostat SYSTEM switch is moved to the HEAT position (either HEAT or AUTO when using autochangeover thermostat P/N 34427DP115).

C. Heating Operation

With the room thermostat SYSTEM switch in the HEAT position and the FAN switch in the AUTO position, the heat ing sequence of operation is as follows:

When the room temperature drops to a point that is slightly

below the heating control setting of the thermostat, the

thermostat first-stage heating bulb “tilts” and thermostat terminal R is automatically connected to thermostat ter minals G and Y. These completed circuits through the ther mostat connect indoor blower relay coil 2A (through unit terminal G) and compressor contactor coil 2D (through unit terminal Y) across the 24-volt secondary of transformer IB.

The set of normally open contacts of energized relay 2A be tween 1 and 3 closes and completes the circuit through indoor hlower motor 3D2. The motor starts instantly.

The two sets of normally open contacts of energized contac tor 2D between 13 and 23, and 11 and 21, close and complete the circuit through compressor motor 3F and outdoor fan motor 3D1. Both motors start instantly. Outdoor fan motor 3D1 operates on high speed, regardless of the outdoor tem perature, because outdoor fan relay contacts 2C are in their normal heating mode positions, as shown in Figure 13. In these normal positions, the line-voltage circuit to fan motor 3D1 is always to the high-speed motor windings, regardless

of the switching action of fan switching thermostat 7K. The heat pump is now operating in the heating mode. The

nonenergized reversing valve is in the normal heating mode position and the high-temperature, high-pressure discharge gas is being directed to the indoor coil, where the heat is transferred to the indoor air.

All three energized motors continue to run, and the heating cycle remains “on” until the room temperature rises to a point that is slightly above the heating control setting of the

room thermostat. If the outdoor temperature has dropped to

the point where the heating capacity of the heat pump can not maintain the desired indoor room temperature, the

second-stage heating bulb will tilt when the indoor tem perature continues to drop to a point that is slightly below the factory differential setting of the room thermostat. Thermostat terminal R is automatically connected to ther mostat terminals W1 and W2. These completed circuits through the thermostat connect the relay coil (or coils if using a two- or three-bank heater) of the supplemental electric heater across the 24-V secondary of heat pump transformer IB. The electric heater energizes to provide sup plemental electric heat to the system.

NOTE: See the Installation Instructions packaged with the electric heater for a more comprehensive description of the electric heater sequence of operation.

When the room temperature rises to a point that is slightly

above the second-stage control setting, the second-stage heating bulb will tilt and break the circuit between ther

mostat terminal R to terminals W1 and W2. The supplemen tal electric heat deenergizes. When the room temperature continues to rise to a point that is slightly above the heating control setting of the room thermostat, the first-stage heat ing bulh tilts and breaks the citcuits between thermostat terminal R to terminals G and Y. These open circuits

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Page 14

deenergize indoor blower relay coil 2A and compressor con tactor coil 2D. All closed contacts return to their normally open position and all three motors stop.

The heat pump has now returned to a “standby” condition awaiting another “call” for heating by the room thermostat. Except for the crankcase hater, all heat pump components

are now deenergized. If the room temperature continues to rise, the heat pump will remain “off” and the cooling mode will not start until the room thermostat SYSTEM switch is moved to the COOL position (either COOL or AUTO when using autochangeover thermostat P/N 34427DP115).

D. Defrost Cycle

The defrost control circuit consists of defrost timer 3M, defrost thermostat switch 7M, and defrost relay 2P. The defrost timer is factory-set for 90-minute intervals of elapsed running time, which results in optimum heating mode efficiency for most installations; however, the adjusta ble cam can be reset for a 30-minute interval when abnormal climatic conditions dictate. These conditions include excessive outdoor humidity at low outdoor temperatures or any condition that results in frequent incomplete de frosting.

CAUTION: Kever adjust the factory-set 9()-minute interval

unless an observed defrosting problem exists. An occasional deposit of frost on the outdoor coil, after a full 10-minute time-terminated defrost cycle, does not indicate that a problem exists. Frequent deposits of frost on the outdoor coil that occur throughout a wide range of outdoor temperatures indicate that a problem does exist.

With the heat pump operating in the heating mode, the defrost cycle sequence of operation is as follows:

Defrost thermostat 7M switches to the closed position when the outdoor coil refrigerant temperature drops to approx imately 30°F. When defrost timer 3M completes 90 minutes of elapsed running time, the normally open timer contacts between 3 and 4 close for approximately 10 seconds. If defrost thermostat is not closed during the 10-second inter val, the defrost cycle does not begin and the defrost control does not “look” for frost for another 90 minutes of elapsed running time.

When normally open defrost timer contacts between 3 and 4 close for their 10-second interval, and defrost thermostat switch 7M has switched close, the defrost control circuit is completed and defrost relay coil 2P is energized.

Energized defrost relay coil 2P switches all of its contacts and each of the following events occur simultaneously:

1. Normally open, high-voltage, defrost relay contacts be tween 7 and 9 close before defrost timer 3M contacts be tween 3 and 4 complete their 10-second interval. The defrost control circuit is maintaned and defrost relay coil 2P remains energized.

2. Normally closed, high-voltage, defrost relay contacts between 7 and 8 open and the circuit through outdoor fan motor 3D1 is broken. The motor stops running.

3. Normally open, low-voltage, defrost relay contacts be tween 1 and 3 close and complete the circuit to revers ing valve solenoid 5B. The reversing valve switches from the normal heating mode position to the cooling mode position and the hot discharge gas is directed to the outdoor coil to melt the frost on the coil.

4. Normally open, low-voltage, defrost relay contacts be tween 4 and 6 close. Unit terminal E is now connected to unit terminal W1 and the first bank of supplemental

electric heat is automatically energized. Terminals W1 and W2 of the room thermostat are internally con nected; therefore, any additional banks of supplemental electric heat are also automatically energized.

The system is now heating the conditioned space with the supplemental heaters while the outdoor coil is defrosting. When the outdoor coil refrigerant temperature rises to ap proximately 67°F, defrost thermostat 7M switches to the open position to terminate the defrost cycle; however, if the defrost thermostat 7M has not terminated the defrost cycle within a 10-minute interval, normally closed timer 3M con tacts between 3 and 5 automatically open and terminate the defrost cycle.

When the defrost cycle is terminated by either the defrost

thermostat or the timer contacts, defrost relay 2P is deenergized. Outdoor fan motor 3D1 restarts and reversing valve solenoid 5B is deenergized. The reversing valve

switches to the nrmal heating mode position. The supple mental electric heaters are deenergized if the room ther mostat is not “calling” for second-stage heating.

The system has now returned to normal heating mode opera tion. After 90 minutes of elapsed running time, defrost timer 3M will automatically make another check to determine if the outdoor coil requires defrosting.

E. Emergency Heat Operation

Thermostats P/N 34427DP115 and 34427DP118 have an emergency heat switch (EM. HT.) which can be used if there is a heat pump malfunction. When the switch is moved from the NORM, position to the EM. HT. position, the compressor and outdoor fan are deenergized, and the unit operates on electrical resistance heat only.

F. Automatic Changeover Operation

When using autochangeover thermostat P/N 34427DP115, switching to either heating or cooling is automatically con trolled by the room thermostat when the SYSTEM switch is in the AUTO position.

To prevent unwanted cycling between heating and cooling mode operation, the heating and cooling temperature selec tion levers provide for a 4°F minimum temperature setting differential. For most installations, this differential will probably be set closer to 10°F to comply with recommended guidelines for energy conservation.

With both the SYSTEM and FAN switches in the AUTO position, the heat pump will start operation in the heating mode when the room temperature drops to a point that is slightly below the heating control setting, or will start operation in the cooling mode when the room temperature rises to a point that is slightly above the cooling control set ting.

VHI. CARE AND MAINTENANCE

To ensure continuing high performance, and to minimize the possibility of premature equipment failure, periodic mainte nance must be performed on this equipment. This packaged heat pump should be inspected at least once each year by a service person who is properly trained and equipped.

NOTE TO EQUIPMENT OWNER: Consult your local Dealer

about the availability of a maintenance contract. WARNING: The ability to properly perform maintenance on

this equipment requires certain expertise, mechanical skills, tools, and equipment. If you do not possess these, do not at tempt to perform any maintenance on this equipment other

than routine filter maintenance. A FAILURE TO HEED THIS WARNING COULD RESULT IN SERIOUS PER SONAL INJURY AND POSSIBLE DAMAGE TO THIS EQUIPMENT.

The minimum maintenance requirements for this equip ment are as follows:

1. Inspect air filter(s) each month. Clean or replace when necessary.

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Page 15

LEGEND

I B-Transformer 2A-lndoor Blower Relay SPST (N.O.) 2C-Outdoor Fan Relay SPOT 2D-Compressor Contactor DPST (N.O.)

2P-Defrost Relay TPDT 3D1-Outdoor Fan Motor 3D2-lndoor Blower Motor 3F-Com pressor 3M-Defrost Timer 4A1-Fan Motor Capacitor 4A2-Blower Motor Capacitor 5B-Reversing Valve Solenoid 7K-Fan Switching Thermostat

SPOT

7M-Defrost Thermostat

Switch (N.O.)

7P-Low-Pressure Switch

SPST (N.O.)

II A-Crankcase Fleater

2. Inspect coils, drain pan, and condensate drain annually. Clean when necessary.

3. Inspect blower motor and wheel for cleanliness, and check lubrication annually. Clean and lubricate when necessary.

4. Check electrical connections for tightness and controls for proper operation annually. Service when necessary.

WARNING: A failure to follow these warnings could result in serious personal injury:

1. Disconnect electrical power to the unit before perform

ing any maintenance or service on the unit. (There may be more than one disconnect switch.)

2. Use extreme caution when removing panels and parts.

As with any mechanical equipment, personal injury can result from sharp edges, etc.

A. Unit Top Removal WARNING: Removal of the unit top must never be at

tempted by anyone other than qualified technicians. CAUTION: The outdoor fan and motor are fastened to the

unit top. When removing the top, use extreme care to not

pull the fan motor leads loose.

NOTE: When performing maintenance or service procedures

that require removal of the unit top, be sure to perform all of the routine maintenance procedures that require top removal; including coil inspection and cleaning, and conden sate drain pan inspection and cleaning.

When performing maintenance and service procedures that require unit top removal, refer to the following top removal procedures:

1. Disconnect electric power to unit.

2. Remove all screws that secure unit top, including screws around four sides and those on top that screw into internal divider panels. Save all screws.

3. Tape all side panels at each seam near unit top. Use tape strips that are at least 5 inches long to prevent sides from falling when top is removed.

4. Lift top from unit carefully. Set top on edge and ensure that top is supported by unit side that is opposite duct

(or plenum) side. Use extreme care to prevent damage to

fan blades, motor, insulation, and coils.

5. Carefully replace and secure unit top to unit, using screws removed in step 2 when maintenance and/or service procedures are concluded. (Be sure to use origi nal screws that have rubber washers to seal out water when securing top to internal divider panels.)

Figure 13—Typical Line-to-Line Wiring Diagram

B. Air Filter

CAUTION: Never operate the unit without a suitable air

filter in the return-air duct system. Always replace the filter with the same size and type. See Table I for recommended filter sizes. '

Inspect air filter(s) at least once each month and replace

(disposable-type) or clean (cleanable-type) at least twice

during each heating and cooling season or whenever the

filter (s) become clogged with dust and lint. Model 542E units do not have factory-supplied air filters.

The field-supplied air filter(s) may be either disposable or cleanable. Model 542D units have two factory-supplied, dis posable-type air filters located in the plenum section of the unit. Remove the access door on the return-air inlet side of the plenum to gain access to the filters. See Figure 4. Re place these filters with the same size and type when necessary.

C. Direct-Drive Indoor Blower and Motor

For longer life, operating economy, and continuing efficien cy; clean accumulated dirt and grease from the blower wheel and motor annually.

Lubricate the motor every 5 years if the motor is used inter mittently (thermostat FAN switch in AUTO position), or every 2 years if the motor is used continuously (thermostat FAN switch in ON position).

WARNING: Disconnect electrical power to the unit before cleaning and lubricating the blower motor and wheel.

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Page 16

Clean and lubricate the direct-drive blower motor and wheel as follows;

1. Remove and disassemble blower assembly as follows; a. Remove blower and control access panels. b. Refer to unit wiring label and disconnect blower

motor leads from their termination points in unit control hox. (Be sure to mark wiring label ap propriately if lead terminations were changed to adjust indoor airflow and changes were not previous ly marked.)

c. Remove blower assembly from unit. Be careful not to

tear insulation in blower compartment.

d. Ensure proper reassembly by marking blower wheel

and motor in relation to blower housing before dis assembly.

e. Loosen setscrew (s) that secures wheel to motor

shaft, remove screws that secure motor mount brackets to housing, and slide motor and motor mount out of housing.

2. Lubricate motor as follows; a. Thoroughly clean all accumulations of dirt or grease

from motor housing.

b. Remove dust caps or plugs from oil ports located at

each end of motor.

c. Use a good grade of SAE 20 nondetergent motor oil

and put one teaspoon, 5cc, 3/16 oz., or 16 to 25 drops in each oil port.

d. Allow time for oil to he absorbed by each bearing,

then wipe excess oil from motor housing.

e. Replace dust caps or plugs in oil ports.

3. Remove and clean blower wheel as follows; a. Ensure proper reassembly by marking wheel orien

tation and cutoff plate location.

b. Remove screws holding cutoff plate, and remove

plate from housing.

c. Lift wheel from housing. When handling and/or

cleaning blower wheel, be sure not to disturb balance weights (clips) on blower wheel vanes, and be sure not to drop or bend wheel.

d. Remove caked-on dirt from wheel and housing with

a brush. Remove lint and/or dirt accumulations from wheel and housing with vacuum cleaner, using soft brush attachment. Remove grease and oil with mild solvent.

e. Reassemble wheel and cutoff plate into housing.

4. Reassemble motor into housing. Be sure setscrew (s) are tightened on motor shaft flats and not on round part of shaft.

5. Reinstall blower assembly into unit and reconnect all

blower motor leads to proper termination points in unit control box. Replace panels.

6. Restore electrical power to unit. Start unit and check

for proper blower rotation and motor speed.

D. Belt-Drive Indoor Blower and Motor (Size 060, 3phase unit)

For longer life, operating economy, and continuing efficien cy; clean accumulated dirt and grease from the blower wheel and motor annually.

Lubricate the motor every 5 years if the motor is used inter mittently (thermostat FAN switch in AUTO position), or every 2 years if the motor is used continuously (theromostat

FAN switch in ON position).

NOTE: Motor may have prelubricated bearings and no oil

ports. When lubrication is required for this type motor, send the motor to a motor repair shop.

WARNING: Disconnect electrical power to the unit before

cleaning and lubricating the blower motor and wheel.

Clean and lubricate the belt-drive blower motor and wheel as follows:

1. Lubricate motor with oil ports as follows; a. Thoroughly clean all accumulations of dirt or grease

from motor housing.

b. Remove dust caps or plugs from oil ports located at

each end of motor.

c. Use a good grade of SAE 20 nondetergent motor oil,

and put one teaspoon, 5cc, 3/16 oz., or 16 to 25 drops in each oil port.

d. Allow time for oil to be absorbed by each bearing,

then wipe excess oil from motor housing.

e. Replace dust caps or plugs in oil ports.

2. Remove and clean blower wheel as follows: a. Refer to unit wiring label, and disconnect blower

motor leads from their termination points in unit control box.

b. Remove blower assembly from unit. Be careful not to

tear insulation in blower compartment. c. Relieve belt tension, then remove belt from pulleys. d. Ensure proper reassembly by marking wheel orien

tation and cutoff plate location. e. Remove screws holding cutoff plate, and remove

plate from housing.

f. Loosen shaft retainer ring setscrew (located on

wheel side of bearing). Loosen two blower wheel

setscrews. Note location of all spacer washers and

retainer rings for proper reassembly, then remove

pulley and shaft from blower assembly.

g. Lift wheel froih housing. When handling and/or

cleaning blower wheel, be sure not to disturb

balance weights (clips) on blower wheel vanes, and

be sure not to drop or bend wheel.

h. Remove caked-on dirt from wheel and housing with

a brush. Remove lint and/or dirt accumulations from wheel and housing with vacuum cleaner, using soft brush attachment. Remove grease and oil with mild solvent. Reassemble wheel, pulley, shaft, and cutoff plate into housing.

i. Reinstall blower assembly. Replace belt and adjust

tension for approximately one inch of sag under nor mal finger pressure midway between pulleys. Recon nect blower motor leads in control box.

E. Outdoor Coil, Indoor Coil, and Condensate Drain Pan

Inspect the outdoor coil, indoor coil, and condensate drain pan at least once each year. Proper inspection and cleaning requires the removal of the unit top. See part A of this sec tion.

The coils are easily cleaned when dry; therefore, inspect and clean the coils either before or after each cooling season. Remove all obstructions including weeds and shrubs that interfere with the airflow through the condenser coil. Straighten bent fins with a fin comb. If coated with dirt or lint, clean the coils with a vacuum cleaner, using the soft brush attachment. Be careful not to bend the fins. If coated with oil or grease, clean the coils with a mild detergent-andwater solution. Rinse coils with clear water, using a garden hose. Be careful not to splash water on motors, insulation, wiring, or air filter (s). For best results, spray outdoor coil fins from inside to outside the unit. Be sure to clean between the inner and outer coils, and to flush all dirt and debris from the unit base.

Inspect the drain pan and condensate drain line when inspecting the coils. Clean the drain pan and condensate drain by removing all foreign matter from the pan. Flush the pan and drain tube with clear water. Do not splash water

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Page 17

TABLE Vlll-TROUBLESHOOTING CHART-HEATING CYCLE

on the insulation, motor, wiring, or air filter(s). If the drain tube is restricted, clear it with a “plumber’s snake” or simi lar probe device.

F. Outdoor Fan CAUTION: Keep the outdoor fan free from all obstructions

to ensure proper operation. Never place articles on top of the unit.

A80090

Inspect the fan blades for cracks or bends each year. Ensure

that blades clear the motor by H4 inch. If the blade assembly

has slipped down the motor shaft, adjust the fan position on the motor shaft by loosening the setscrew (s) then moving the blade assembly up. Be sure that the setscrew(s) is on the flat(s) of the motor shaft before tightening.

G. Electrical Controls and Wiring

Inspect and check the electrical controls and wiring annu-

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Page 18

TABLE IX-TROUBLESHOOTING CHART-COOLING CYCLE

ally. Be sure to disconnect the electrical power to the unit. Remove the control, blower, and compressor compartment access panels to locate all the electrical controls and wiring. Check all electrical connections for tightness. Tighten all screw connections. If any smoky or burned connections are noticed: disassemble the connection, clean all the parts, restrip the wire end, and reassemble the connection properly and securely.

After inspecting the electrical controls and wiring, replace

all the panels. Start the unit, and observe at lease one com plete cooling cycle and one complete heating cycle (tem perature permitting) to ensure proper operation. If discre pancies are observed or a suspected malfunction has occured, check each electrical component with the proper electrical instrumentation. Refer to the unit wiring label when making these checkouts.

NOTE: Refer to the sequences of operation in this publica tion as an aid in determining proper control operation.

H. Refrigerant Circuit

Inspect all refrigerant tubing connections and the unit base for oil accumulations annually. Detecting oil genrally indi cates a refrigerant leak.

If oil is detected or if diminished performance is suspected, leak-test all refrigerant tubing; using an electronic leak detector, halide torch, or liquid soap solution. If a refrigerant leak is detected, see Section V, part B, “Refrigerant Leaks,” in this publication.

If no refrigerant leaks are found and diminished perfor mance is suspected, see Section VI, part B, “Checking and Adjusting Refrigerant Charge,” in this publication.

I. Indoor Airflow

The indoor airflow does not require checking unless improper performance is suspected. If a problem exists, he

sure that all supply-and return-air grilles ae open and free from obstructions, and that the air filter (s) is clean. When

necessary, refer to Section VI, part C, of this publication to check the system airflow.

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