Bryant 541A User Manual

installation, start-up and
service instructions

SPLIT SYSTEM
HEAT PUMP UNITS

Cancels: II 541A-120-1 II 541A-120-2

541A

Sizes 120,180
10 to 15 Tons

12/15/98

CONTENTS

Page

SAFETY CONSIDERATIONS ........................1

INSTALLATION ................................1-10

I. Step 1 — Complete Pre-Installation Checks .....1

II. Step 2 — Rig and Mount Unit .................1

III. Step 3 — Complete Refrigerant Piping

Connections ...............................2

IV. Step 4 — Complete Electrical Connections .....8

PRE-START-UP ................................10-12

START-UP ....................................12-14

SERVICE .....................................14,15

TROUBLESHOOTING ...........................16-19

START-UP CHECKLIST ....................CL-1, CL-2

SAFETY CONSIDERATIONS

Installing, starting up, and servicing this equipment can be
hazardous due to system pressures, electrical components and
location of equipment (roofs, elevated structures, etc.).

Only trained, qualified installers and servicemechanicsshould
install, start up, and service this equipment.

Untrained personnel can perform basic maintenance func­tions, such as cleaning coils and filters and replacing filters.
All other operations should be performed by trained service
personnel.

When working on the equipment, observe precautions in the
literature and on tags, stickers, and labels attached to the
equipment.

• Follow all safety codes.

• Wear safety glasses and work gloves.

• Keep a quenching cloth and fire extinguisher handy.

• Use care in handling, rigging, and setting bulky

equipment.

WARNING:

to equipment is shut off before performing mainte­nance or service.

IMPORTANT: Follow unit location, height proximity, and pip­ing requirements in this booklet carefully to enhance system
efficiency and to avoid system failure. Read entire booklet be­fore starting installation.

I. STEP 1 — COMPLETE PRE-INSTALLATION CHECKS
A. Uncrate Unit

Remove unit packaging except for thetopskidassembly, which
should be left in place until after the unit is rigged into
position.

To prevent electric shock, be sure power

INSTALLATION

B. Inspect Shipment

File claim with shipping company if shipment is damaged or
incomplete.

C. Consider System Requirements

• Consult local building and electrical codes for special in­stallation requirements.

• Allow sufficient space for airflow clearance, wiring, refrig­erant piping, and servicing unit. See Fig. 1 and 2.

• Ensure unit weight will be properly supported. See
Table 1.

• Unit may be mounted on a level pad directly on the base
channels or mounted on raised pads at support points. See
Fig. 3 and Table 2 for weight distribution based on recom­mended support points.

NOTE: If vibration isolators are required for a particular in­stallation, use data in Table 2 to make proper selection.

• Accessory mounting legs (Part No. 309273-227) are recom­mended for elevation of unit for improved air circulation
and better condensate drainage. Legs also minimize inter­ference from ice build-up, snow, leaves, and debris. See
Fig. 1.

II. STEP 2 — RIG AND MOUNT UNIT

CAUTION:

prior to rigging. Be careful rigging, handling, and in­stalling unit. Improper unit location can cause system
malfunction and material damage. Inspect base rails for
any shipping damage and make sure they are fastened
securely to unit before rigging.

A. Rigging

Units are designed for overhead rigging only. For this pur­pose, the transverse base rails extend beyond sides of unit,
with holes provided in end plates to attach clevis for secur­ing cables. Rig with top skid packaging assembly in place to
prevent unit damage by rigging cable. For coil face protec­tion, place plywood sheets against the sides of unit, behind
cables. Run cables to a central suspension point so that the
angle from the horizontal is not less than 45 degrees. Raise
and set unit down carefully.

If it is necessary to roll unit into position, mount unit on field­supplied longitudinal rails using a minimum of 3 rollers.AP­PLY FORCE TO THE RAILS, NOT THE UNIT. If unit is to
be skidded into position, place it on a large pad and drag the
pad. DO NOT APPLY ANY FORCE TO THE UNIT.

Raise from above to lift unit from rails or pad when placing
unit in final position.

Be sure unit panels are securely in place

Table 1 — Physical Data

UNIT 541A 120 180

OPERATING WEIGHT (lb) 750 803
REFRIGERANT R-22 R-22

Operating Charge (lb)* 30 37

COMPRESSOR Recip Hermetic; 1750 Rpm

Model No. 06DF824 06DF537
Cylinders 66
Oil (pts) 10 10
Crankcase Heater (Watts) 180 180

OUTDOOR AIR FANS Direct Drive — Axial Flow

Number 22
Speed (rpm) 1075 1075
Diameter (in.) 26 26
Motor Hp
Airflow (cfm) 11,000 11,000
kW (total) 1.46 1.46

OUTDOOR COIL Plate Fins; 15 Per Inch

Rows Deep 23
Face Area (sq ft) 29.2 29.2
Storage Capacity (lb)† 27.2 40.1

CONTROLS

High-Pressure Switch (HPS)

Cutout (psig) 400
Cut-in (psig) 300

Loss-of-Charge Switch

(Liquid Line)

Cutout (psig) 7 6 3
Cut-in (psig) 22 6 5

Head Pressure

(No. 2 Fan Cycling)**

Opens (psig) 160±10
Closes (psig) 255±10

Oil Pressure Switch (Differential)

Set Point (psig)

(Close on Rise) 9.5 6 1
(Open on Fall) 5

Defrost Pressure Switch (HPS2)

Opens (psig) 280 6 10
Closes (psig) 180 6 2

THERMOSTAT

Defrost Switch

Opens (F) 65 80
Closes (F) 27 27

*Approximate charge with 25 ft of interconnecting piping. Use

appropriate charging charts for actual charging of unit.

†Refrigerant storage capacity at 120 F condensing temperature with

condenser 80% full of liquid.

**Head pressure control on cooling cycle only.

1

⁄

2

1

⁄

2

B. Locate Unit

For service access and unrestricted airflow,provide2 ft clear­ance on each end of unit and 3 ft clearance on each side of
unit. Position unit so that there is unrestricted airflow above
unit.

NOTE: Before mounting unit, remove 4 holddown brackets
and release skid.

If conditions or local codes require unit to be fastened to
pad, use the mounting holes in the 4 unit mounting feet (see
Fig. 1).

C. Mount Unit

The unit may be mounted on a solid, level concrete pad, on
accessory mounting legs, or on field-supplied raised supports
at each mounting position. (Note that mounting hardware is
field supplied.)

Weightdistribution (shown in Fig. 3 and Table 2) determines
the type of support required. Bolt unit securely to pad or sup­ports after unit is in position and is level. Be sure to mount
unit level to ensure proper oil return to compressors. Mount­ing holes on unit can be used to secure unit to vibration iso­lators, if required.

D. Compressor Mounting

As shipped, compressor is held down by 4 bolts. After unit is
installed, loosen each bolt using locknut shown in Fig. 4 un-

3

til flat washer (

⁄8in.) can be moved with finger pressure.

III. STEP 3 — COMPLETE REFRIGERANT PIPING

CONNECTIONS

Refrigerant lines must be carefully designed and constructed
to ensure equipment reliability and efficiency. Line length,
pressure drop, compressor oil return, and vertical separation
are several of the design criteria that must be evaluated. See
the following sections.

IMPORTANT: Piping must be properly sized and installed for
the system to operate efficiently.

A. Check Vertical Separation

If there is any vertical separation between the indoor and out­door units, checkT able3 to ensure that the separation is within
allowable limits. Relocate equipment if necessary.

—2—

Fig. 1 — Dimensions

—3—

12 3 45 6 78 9101112

13

14
15

28

27

26

1—Defrost Board/Time GuardT II Control
2—Fuse
3—Fan No. 1
4—Signal-LOC™ Device
5—Outdoor-Fan Relay
6—Outdoor-Fan Contactor
7—Compressor Contactor
8—Fan Motor Capacitors
9—Circuit Breaker

10 — Fan No. 2

38 1/4"

2

LEGEND

11 — Power Terminal Block
12 — Control Terminal Block
13 — Compressor Lockout (CLO2 for

Crankcase Heater)

14 — Control Relay (CR3)
15 — Liquid Line Solenoid
16 — Control Relay (CR2)
17 — No Dump Relay (NDR)
18 — Oil Pressure Switch
19 — Fusible Plug (hidden)

Fig. 2 — Component Locations

4

26 11/16"

UNIT

541A

120 750 147 228 228 147
180 803 158 243 244 158

19202122232425

20 — High-Pressure Switch
21 — Compressor
22 — Capacity Control Solenoid
23 — Filter Drier
24 — Muffler
25 — Oil Solenoid
26 — Reversing Valve
27 — Accumulator
28 — Coil

Table2—Weight Distribution

WEIGHT — lb

Total

Operating

Weight

1234

Support Point

(Fig. 3)

16

17

18

541A120, 180

1

3

Fig.3—Weight Distribution

Table 3 — Maximum Vertical Separation*

OUTDOOR

UNIT
541A

INDOOR

UNIT

524A-H

Above Outdoor

DISTANCE — FT

Unit

Indoor Unit

Below Outdoor

Unit

120 120 50 50
180 180 80 80

*Vertical distance between indoor and outdoor units.

—4—

Fig. 4 — Compressor Mounting

B. Refrigerant Line Design and Sizing

Consider the length of the piping required between the out­door and indoor units. The maximum allowable line length is
100 ft. Select proper liquid and vapor line sizes from Table 4.
Contact your local representative if assistance is required for
design details and proper piping practices.

Table 4 — Piping Selection and Refrigerant

Charge Data

OUTDOOR

UNIT
541A

120
180

120 30 38 46 48
180 37 45 59 62

LEGEND

L—Liquid Line
V—Vapor Line

*Approximately 4 elbows assumed in determining pipe sizes.

†Maximum length of interconnecting piping is 100 ft.

**Approximate system charge is for estimating only. It includes charge

requirements for one outdoor unit, matching indoor coil, and intercon­necting piping. See Preliminary Charge section on page 10.

NOTE: If there is a vertical separation between indoor and outdoor units,
see Table 3. Double vapor line riser may be required.

LENGTH 0F PIPING — FT*

0-25 25-60 60-100†

Line Size (in. OD)

LVLVLV

5

⁄811⁄

5

⁄813⁄

Approximate System Charge

5

8

⁄813⁄

3

8

⁄415⁄

lb**

8
8

5

⁄815⁄

3

⁄415⁄

8
8

MAXIMUM

LIQUID

LINE OD

(in.)

5

⁄

8

3

⁄

4

Maximum

Charge —

lb

Carefully evaluate any vapor risers at minimum load condi­tions to ensure proper compressor oil return. If the indoor
unit is above the outdoor unit, the riser will function as a hot
gas riser.If the outdoor unit is above the indoor unit, the riser
is a suction riser. Design and construct a double riser if nec­essary. Contact your local representative if assistance is
required.

C. Liquid Line Piping Procedure

Pipe the system liquid line as follows:

WARNING:

Unit is pressurized with a holding charge
of refrigerant. Recover R-22 holding charge before re­moving runaround liquid piping loop. Failure to re­cover holding charge before removing piping loop could
result in equipment damage and severe injury.

1. Open service valves in sequence:
a. Discharge service valve on compressor.
b. Suction service valve on compressor.
c. Liquid line valve.

2. Remove

1

⁄4-in. flare cap from liquid valve Schrader port.

3. Attach refrigerant recovery device and recover holding
charge.

4. Remove runaround loop.

5. Connect system liquid line from liquid connection of out­door (541A) unit to indoor unit liquid line connections.
See Fig. 5 for typical piping and wiring. Select proper
field-supplied bi-flow filter driers and install in the liq­uid line. See Fig. 6. Install a field-supplied liquid mois­ture indicator between the filter drier(s) and the liquid
connections on the indoor (524A-H) unit. Braze or silver
alloy solder all connections. Pass nitrogen or other inert
gas through piping while making connections to pre­vent formation of copper oxide. (Copper oxides are ex­tremely active under high temperature and pressure.
Failure to prevent collection of copper oxides may re­sult in system component failures.)

D. Vapor Line Piping Procedure

Connect system vapor line to the vapor line stub on the out­door unit and the vapor stubs on the indoor unit. At the in­door unit, construct vapor piping branches as shown in Fig. 7
for good mixing of the refrigerant leaving the indoor coil dur­ing cooling. This will ensure proper TXV (thermostatic ex­pansion valve) bulb sensing.

Where vapor line is exposed to outdoor air, line must be in­sulated. See Table 5 for insulation requirements.

—5—

LEGEND

NEC — National Electrical Code
TXV — Thermostatic Expansion Valve

*Field supplied.

Piping

NOTES:

1. All piping must follow standard refrigerant piping techniques.

2. All wiring must comply with applicable local and national codes.

3. Wiring and piping shown are general points-of-connection guides
only and are not intended for, or to include, all details for a spe­cific installation.

4. Filter driers must be bi-flow type suited for heat pump duty.

5. Internal factory-supplied TXVs and check valves not shown.

Fig.5—Typical System Piping and Wiring

—6—

BI-FLOW FILTER DRIER

LIQUID LINE

TXV

A

B

REDUCING TEE

UNIT

541A

120

180

LIQUID

LINE

SIZE (in.)

1

⁄

2

5

⁄

8

1

⁄

2

5

⁄

8

LEGEND

TXV — Thermostatic Expansion Valve

Fig. 6 — Recommended Filter Driers and Installation Locations

A

INDOOR COIL

PART NO.

QUANTITY

REQUIRED

FIGURE

REFERENCE

P504-8084S 2 A
P504-8165S 1 B
P504-8084S 2 A
P504-8085S 2 A

LEGEND

TXV — Thermostatic Expansion Valve

Fig.7—Vapor Line Branch Piping Details

Table 5 — Insulation for Vapor Line Exposed to Outdoor Conditions

LENGTH OF EXPOSED

VAPOR LINE*

ft in.
10
25
35
50

*Recommended vapor line insulation for piping exposed to outdoor conditions to

prevent loss of heating during heating cycle. When vapor line goes through inte­rior spaces, insulation should be selected to prevent condensation on cooling cycle.
Heating capacity should be reduced 1000 Btuh if over 35 ft of vapor line with

3

⁄4in. insulation is exposed to outdoor conditions.

†Closed cell foam insulation with a thermal conductivity of:

0.28 Btu • in/ft2•h•°F.

INSULATION THICKNESS†

3

⁄

8

1

⁄

2

3

⁄

4

3

⁄

4

—7—

E. Provide Safety Relief

A fusible plug is located on the compressor crankcase
(Fig. 8). Do not cap this plug. If local code requires additional
safety devices, install as directed.

Head Pressure Control
Fan cycling for head pressure control is a standard offering

but is functional on the cooling cycle only. Number 2 fan cycles
as a function of liquid pressure. Fan cycling pressure switch
cycles the fan off at 160 ± 10 psig as pressure decreases and
cycles back on at 255 ± 10 psig. Switch is automatically by­passed in heating cycle. Table 6 shows minimum outdoor am­bient air temperature for full cooling capacity.

C. Unbalanced 3-Phase Supply Voltage

Never operate a motor where a phase imbalance in supply
voltage is greater than 2%. Use the following formula to de­termine the percentage of voltage imbalance:

% Voltage Imbalance:
= 100 x

max voltage deviation from average voltage

average voltage

EXAMPLE: Supply voltage is 460-3-60.

AB = 452 v
BC = 464 v
AC = 455 v

Fig. 8 — Location of Fusible Plug

Table 6 — Minimum Outdoor Air

Operating Temperature

UNIT
541A

120

180

*Applies to Cooling mode of operation only.

%

COMPRESSOR

CAPACITY

100 90 35

67 80 45

100 90 23

67 80 36

OUTDOOR COIL

TEMP — F

MINIMUM

OUTDOOR

TEMP — F*

Standard Unit

IV. STEP 4 — COMPLETE ELECTRICAL CONNECTIONS
A. Power Supply

Electrical characteristics of available power supply must agree
with nameplate rating. Supply voltage must be within toler­ances shown in Table 7. Phase unbalance must not exceed
2%. Operation of unit on improper supply voltage or with ex-

cessive phase imbalance constitutes abuse and is not covered
by warranty.

Per local code requirements, provide an adequate fused dis­connect switch within sight of unit and out of reach of chil­dren. Provision for locking switch open (off) is advisable to
prevent power from being turned on while unit is being ser­viced. The disconnect switch, fuses, and field wiring must com­ply with local requirements. Refer to Table 7 for electrical
data. Route power wiring through entrance in right-hand cor­ner post of unit. The power terminal block is sized to handle
either copper or aluminum wires. Unit must be grounded. Af­fix crankcase heater warning sticker to unit disconnect switch.

B. Power Wiring

All power wiring must comply with applicable local require­ments. Install a field-supplied branch circuit disconnect switch
that can be locked off or open. Run power wires from discon­nect switch through unit power opening and connect to ter­minal block inside the unit control box. See Fig. 9.

Average Voltage =

452 + 464 + 455

3

= 457 v

Determine maximum deviation from average voltage:

(AB) 457 − 452 = 5 v
(BC) 464 − 457 = 7 v
(AC) 457 − 455 = 2 v

Maximum deviation is 7 v. Determine percentage of voltage
imbalance:

% Voltage Imbalance = 100 x

7

457

= 1.53%

This amount of phase imbalance is satisfactory as it is
below the maximum allowable of 2%.

IMPORTANT: Contact your local electric utility company
immediately if the supply voltage phase imbalance is more
than 2%.

WARNING:

Unit cabinet must have an uninterrupted,
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 unit
ground lug in control compartment, or conduit ap­proved for electrical ground when installed in accor­dance with NEC (National Electrical Code), ANSI/
NFPA(AmericanNational Standards Institute/National
Fire Protection Association), and local electrical codes.
Failure to follow this warning could result in the
installer being liable for personal injury of others.

IMPORTANT: Operation of unit on improper power supply volt­age or with excessive phase imbalance constitutes abuse and
is not covered by Bryant warranty.

D. General Wiring Notes

1. A crankcase heater is wired in the control circuit so it is
always operable as long as power supply disconnect is
on, even if any safety device is open or unit stop/start
switch is off.

2. The power-circuit field supply disconnect should never

be open except when unit is being serviced or is to
be down for a prolonged period. When operation is
resumed, crankcase heater should be energized for 24 hours
before start-up. If system is to be shut down for a pro­longed period, it is recommended that the suction and
discharge valves be closed to prevent an excessive
accumulation of refrigerant in the compressor oil.

3. Terminalsfor field power supply are suitable for copper,
copper-clad aluminum, or aluminum conductors.

—8—