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—
TERMINAL BOARD (TB1) IN
UNIT CONTROL BOX
21
22
23
EQUIP GND
11
12
13
LEGEND
CAP — Capacitor
EQUIP — Equipment
GND — Ground
NEC — National Electrical Code
Field Wiring
Factory Wiring
Fig. 9 — Main Power Supply Wiring
Table 7 — Electrical Data (3 Ph/60 Hz)
UNIT COMPRESSOR FAN MOTORS (Single-Phase)
541A
120
180
FLA — Full Load Amps (fan motors)
ICF — Maximum Instantaneous Current Flow during start-up
LRA — Locked Rotor Amps
MCA — Minimum Circuit Amps per NEC Section 430-24
MOCP — Maximum Overcurrent Protection (fuse only)
RLA — Rated Load Amps (compressor)
Model
501 208-230 187 253 62.5 178 100 43.6 170
601 460 414 528 29.1 81 40 20.0 77 2.3 1.9
501 208-230 187 253 87.5 274 125 63.6 266
601 460 414 528 40.7 124 60 29.3 120 2.3 1.9
Name-
plate
(LRA of compressor plus total FLA of fan motors)
Volts
Supplied*
MCA ICF
Min Max 12
LEGEND
DISCONNECT PER NEC
OR LOCAL CODE
MOCP
(Amps)
Fuse Only
RLA LRA
Total
Fans
2
2
*Units are suitable for use on electrical systems where voltage supplied
to the unit terminals is not below or above the listed limits.
NOTES:
1. MCA and MOCP values are calculated in accordance with NEC
(National Electric Code), Article 440.
2. Motor RLA and FLA values are established in accordance with
UL (Underwriters’ Laboratories) Standard 1995.
FLA (ea)
Fan No.
4.3 3.7
4.3 3.7
—9—
E. Control Circuit Wiring
Unit internal control circuit voltage is 24 volts. See Table 8
for recommended thermostats. Connect thermostat assembly
and other accessories as shown in unit label diagram and
Fig. 10. Refer to installation instructions shipped with indoor unit. See Fig. 11 for field-supplied airflow switch wiring
if airflow switch is used. The control wiring entrance is located on right corner post of 541A unit. See Fig. 1. Wiring
connects to a terminal block located at extreme right of control box.
Transformers no. 1 and 2 are wired for a 230-v unit. If a 208/
230-v unit is to be run with a 208-v power supply, the transformers must be rewired as follows:
1. Remove cap from red (208 v) wire.
2. Remove cap from orange (230 v) spliced wire.
3. Replace orange wire with red wire.
4. Recap both wires.
IMPORTANT: BE CERTAIN UNUSED WIRES ARE CAPPED.
Failure to do so may damage the transformer.
Route thermostat cable or equivalent single leads of no. 18 AWG
(American Wire Gage) colored wire from subbase terminals
through conduit in unit to low-voltage connections as shown
on unit wiring diagram and Fig. 10.
NOTE: For wire runs up to 50 ft, use no. 18 AWG insulated
wire (35 C minimum). For 51 to 75 ft, use no. 16 AWG insulated wire (35 C minimum). For over 75 ft, use no. 14 AWG
insulated wire (35 C minimum).All wire larger than no. 18AWG
cannot be directly connected to the thermostat and will require a junction box and a splice at the thermostat.
F. Electric Resistance Crankcase Heater
The crankcase heater is inserted into the compressor crankcase. The crankcase heater is operated from the normally closed
contacts of the control relay (CR1) and is automatically
energized when compressor stops. This heater keeps crankcase warm to prevent oil dilution by refrigerant, ensures good
lubrication, and minimizes loss of oil during start-up.
G. Airflow Switch
Bryant recommends an indoor airflow switch (field supplied)
be installed and interlocked with the outdoor unit. This prevents the outdoor unit from operating if indoor airflow fails
(broken fan belt, etc.). Operation of the compressor in vacuum
can damage bearing surfaces. Install indoor airflow switch in
a convenient location at the indoor supply air duct and wire
per Fig. 11.
PRE-START-UP
IMPORTANT: Before beginning Pre-Start-Up or Start-Up, re-
view Start-Up Checklist at the back of this book. The checklist assures proper start-up of the system and provides a record
of unit condition, application requirements, system information, and operation at initial start-up.
CAUTION:
system, even momentarily,until the following steps have
been completed. Compressor damage may result.
I. SYSTEM CHECK
1. Check all air handler and other equipment auxiliary
components. If unit has field-installed accessories, be
sure all are properly installed and correctly wired. If
used, airflow switch must be properly installed. See
Fig. 11.
Do not attempt to start the heat pump
2. Backseat (open) compressor suction and discharge valves.
Now close valves one turn to allow refrigerant pressure to reach test gages.
3. Open liquid line service valve.
4. Check tightness of all electrical connections.
5. Compressor oil level should be visible in sight glass.
Adjust the oil level as required. No oil should be
removed unless the crankcase heater has been energized for at least 24 hours. See Start-Up section, Preliminary Oil Charge on page 12.
6. Be sure unit is properly leak checked, dehydrated, and
charged. See Preliminary Charge, this page.
7. Electrical power source must agree with nameplate
rating.
8. Crankcase heater must be firmly locked into compres-
sor crankcase. Be sure crankcase is warm (heater must
be on for 24 hours before starting compressor).
9. Be sure compressor floats freely on the mounting springs
and that upper flat washers can be moved with finger pressure. See Compressor Mounting, page 2, and
Fig. 4 for loosening compressor bolts.
II. LEAK TEST AND DEHYDRATION
Leak test the entire refrigerant system using soap bubbles
and/or an electronic leak detector. Evacuate and dehydrate
entire refrigerant system by use of methods described in
GTAC II, Module 4, System Dehydration.
III. TURN ON CRANKCASE HEATER
Turnon crankcase heater for 24 hours before starting the unit
to be sure all refrigerant is out of the oil. To energize crankcase heater, perform the following steps:
1. Set the space thermostat system switch to OFF, or adjust the temperature so there is no demand for cooling.
2. Close the field disconnect.
3. Leave the compressor circuit breaker off. The crankcase
heater is now energized.
IV. PRELIMINARY CHARGE
Refer to GTAC II, Module 5, Charging, Recovery, Recycling,
and Reclamation for charging methods and procedures. Charge
with R-22 by the liquid charging method (through liquid service valve) on the high side. See approximate refrigerant charge
in Table 4. Charge according to the values in the Charging
Chart, Fig. 12 and 13, page 14.
V. THERMOSTAT ANTICIPATOR ADJUSTMENT
A. Heating/Cooling Thermostat (HH621606)
The thermostat has an adjustable heat anticipator for both
first- and second-stage heating circuits.
B. Settings
Set adjustment lever for first-stage anticipator at 0.79 (lefthand side). Set adjustment lever for second-stage anticipator
(right-hand side) at 0.42.
C. Outdoor Thermostat
Refer to 524A-H accessory heater installation instructions for
details of this thermostat (if used).
—10—
Table 8 — Recommended Thermostat
THERMOSTAT NO. HH621606 (°F)
SUBBASE NO. HH93AZ174*
Type Standard
Display — °F
2 Cooling Stages X
2 Heating Stages X
Auto Changeover X
Fan Switch X*
Emergency Heat X
*Subbase has ON-AUTO fan switch. Use emergency heat relay part no. HN65DZ026.
Fig. 10 — Field Wiring Diagram, 541A120 or 180 System with
Standard Thermostat and Electric Heat
—11—
LEGEND
EQUIP — Equipment
GND — Ground
HC — Heater Contactor
IFC — Indoor Fan Contactor
IFM — Indoor Fan Motor
NEC — National Electrical Code
TB — Terminal Block
LEGEND
AFS — Airflow Switch (Sail Switch)
DB — Defrost Board
HR — Heat Relay
NOTES:
1. LocateYEL wire between on DB and terminal 5 of HR and cut.
2. Splice airflow switch (AFS) (field supplied) contact wires (field pro-
Factory Wiring
Field Wiring
Y
vided) to two ends of cut YEL wire as depicted.
Fig. 11 — Field Wiring for Airflow Switch —
541A120,180/524A-H
START-UP
Compressor crankcase heater must be on for 24 hours
before start-up. To energize the crankcase heater,set the space
thermostat above the ambient temperature so there is no
demand for cooling. Close the field disconnect. Leave the compressor circuit breaker off/open. The crankcase heater is now
energized.
After the heater has been on for 24 hours, the unit can be
started. If no time has elapsed since the preliminary charge
step was completed, it is unnecessary to wait the 24-hour
period.
NOTE: Use only approved compressor oil. Approved sources
are:
Petroleum Specialties Inc. ..................Cryol 150A
Texaco, Inc. ...........................Capella WF-32
Witco Chemical Co. .......................Suniso 3GS
Do not use oil that has been drained out, or oil that has been
exposed to atmosphere.
B. Remove Oil
1
Pump down compressor to 2 psig. Loosen the
⁄4-in. pipe plug
at the compressor base and allow the oil to seep out past the
threads of the plug. Retighten plug when level is correct.
NOTE: The crankcase is slightly pressurized. Do not
remove the plug, or the entire oil charge will be lost.
Small amounts of oil can be removed through the oil pump
discharge connection while the compressor is running.
III. START UNIT
Close the field disconnect and set the space thermostats above
ambient temperature so that there is no demand for cooling.
Only the crankcase heaters will be energized.
Next, close the compressor circuit breakers. Place thermostat selector switch at COOL and set space set point below
ambient temperature so that a call for cooling is ensured. If
compressor does not start, set thermostat lower.
NOTE: Do not use circuit breaker to start and stop the compressor except in an emergency.
CAUTION:
Never charge liquid into the low-pressure
side of system. Do not overcharge. During charging or
removal of refrigerant, be sure indoor-fan system is
operating.
I. PRELIMINARY CHECKS
1. Ensure that compressor service valves are backseated.
2. Verify that the compressor floats freely on its mounting
springs.
3. Check that electric power supply agrees with unit nameplate data.
4. Verify that compressor crankcase heater is securely in
place.
5. Check that compressor crankcase heater has been on at
least 24 hours.
6. Check to see if compressor oil level is visible in the sight
glass. If oil level adjustment is required, see the following Preliminary Oil Charge section.
7. Recheck for leaks using same procedure as previously
outlined in Pre-Start-Up section, Leak Test and Dehydration, page 10.
8. If any leaks are detected, evacuate and dehydrate as previously outlined in Pre-Start-Up section, Leak Test and
Dehydration, page 10.
II. PRELIMINARY OIL CHARGE
The compressor is factory charged with oil (see Table1). When
oil is checked at start-up, it may be necessary to add or remove oil to bring it to the proper level. One recommended oil
level adjustment method is as follows:
A. Add Oil
Close suction service valve and pump down crankcase to
2 psig. Wait a few minutes and repeat until pressure remains steady at 2 psig. Remove oil fill plug above the sight
glass, add oil through plug hole, and replace plug. Run compressor for 20 minutes and check oil level.
IV. ADJUST REFRIGERANT CHARGE
NOTE: The remaining start-up procedures and all refriger-
ant charge modifications should be done only under supervision of a qualified refrigeration mechanic.
Withall fans operating, and compressor operating fully loaded,
adjust the refrigerant charge in accordance with the unit charging charts located on the inside of the control box doors and
in Fig. 12 and 13.
CAUTION:
Charge unit on cooling cycle only. If unit
is charged on heating cycle, overcharging may occur.
1. Be sure to use Refrigerant-22.
2. Regulate refrigerant drum valve to maintain suction pressure at 80 psig while charging. Charge with vapor only,
at suction side of unit.
NOTE: Do not depend on sight glass when charging unit. Use
charging chart.
Allow system to operate for 20 minutes. Take temperature
and pressure readings at liquid line service valve and check
values with the charging chart.
Plot point on charging chart. If point is above curve, add charge.
If point is below curve, reduce charge until point falls on line.
Record the final refrigerant charge.
If the sight glass is cloudy, check refrigerant charge again.
Ensure all fans are operating. Also ensure maximum allowable liquid lift has not been exceeded. If charged per chart
and if the sight glass is still cloudy, check for a plugged filter
drier or a partially closed solenoid valve. Replace or repair,
as needed.
—12—
V. CHECK HEATING CYCLE OPERATION
Place thermostat selector switch at HEATand reset the space
set point above ambient temperature so that a call for heating is ensured. Compressor will start within 5 minutes. Observe system operation.
VI. CHECK COMPRESSOR OIL LEVEL
After adjusting the refrigerant charge, allow the system to
run fully loaded for 20 minutes. Running oil level should be
within view in the crankcase sight glass. Stop the compressor at the field power supply disconnect and check the crankcase oil level. Add oil only if necessary to bring the oil into
view in the sight glass. If oil is added, run the system for an
additional 10 minutes, then stop and check oil level. If the
level remains low, check the piping system for proper design
for oil return; also check the system for leaks.
If the initial check shows too much oil (too high in the sight
glass) remove oil to proper level. See Preliminary Oil Charge,
page 12, for proper procedure for adding and removing oil.
When the above checks are complete, repeat the procedure
with the unit operating at minimum load conditions.
Unload the compressor by disconnecting the field-control
circuit lead at TB2 .
Reconnect the field-control circuit lead when checks are
complete.
VII. FINAL CHECKS
Ensure all safety controls are operating, control panel covers
are on, and the service panels are in place.
VIII. SEQUENCE OF OPERATION
A. Heating
Place thermostat selector at HEAT and set temperature selector above room ambient.
B. Cooling
Place thermostat selector at COOL and set temperature selector below room ambient.
When thermostat calls for unit operation (either heating or
cooling), the indoor-fan motor starts immediately.The outdoorfan motors and compressor start within 3 seconds to 5 minutes depending on when unit was last shut off by thermostat,
because unit contains a Time Guardt circuit. When firststage cooling is required, thermostat (TC1) closes, causing the
heat pump to start with an unloaded compressor. When TC2
closes, demanding additional cooling, the compressor loads
to full load operation.
During heating, compressor is always fully loaded. When TH1
demands first-stage heating, the heat pump starts within
3 seconds to 5 minutes depending on when unit was last
shut off by thermostat, because unit contains a Time Guard
circuit. (The defrost board has speed terminals to shorten this
cycle.) When TH2 of the thermostat closes, auxiliary heat supply (electric strip heat) is energized in 1 or 2 stages depending on number of stages available and whether outdoor thermostats are closed.
Defrost is achieved by reversal from heating to cooling cycle
and deenergization of outdoor-fan motors, allowing hot refrigerant gas to defrost outdoor coil. Defrost is achieved with
a timer set to initiate defrost every 30, 50 or 90 minutes (factory set at 30 minutes).
Defrost is initiated when refrigerant temperature leaving the
outdoor coil is measured below 27 F, (typically when the outdoor ambient temperature is below 45 F as sensed by the defrost thermostat [DFT]).
Y2
Defrost is terminated when: The refrigerant temperature rises
to 65 F (80 F for 541A180) at the DFT location on the liquid
line; or the refrigerant pressure rises to 280 psig at the HPS2
location on the liquid line; or the defrost timer completes the
10-minute cycle.
Malfunction
The high-pressure switch, loss-of-charge switch, oil pressure
safety switch, and compressor overtemperature safety are located in a Signal-LOC™ circuit that prevents heat pump operation if these safety devices are activated. A light at the
thermostat energizes when Signal-LOC circuit is affected.The
lockout system can be reset by adjusting the thermostat to
open the contacts (down for Heating mode, up for Cooling mode),
deenergizing the Signal-LOC circuitry. Compressor overcurrent protection is achieved with a circuit breaker which requires manual resetting at the outdoor unit control box.
The unit is equipped with an oil pressure safety switch that
protects the compressor if oil pressure does not develop on
start-up or is lost during operation. The oil pressure switch
is of the manual reset type and therefore must be reset at
the outdoor unit. DO NOT RESET MORE THAN ONCE.
If oil pressure switch trips, determine cause and correct. DO
NOT JUMPER OIL PRESSURE SAFETY SWITCH.
To reset the oil pressure switch:
1. Disconnect power to the unit.
2. Press the RESET button on the oil pressure switch.
3. Reconnect power to the unit.
Unit is equipped with a no-dump reversing valve circuit. When
unit is in Cooling mode, reversing valve remains in cooling
position until a call for heating is requested by thermostat.
When unit is in Heating mode, reversing valve remains in
heating position until there is a call for cooling.
The crankcase heater is in a lockout circuit. If crankcase heater
is defective, compressor is locked off. Heat pump remains off
until corrective action is taken. The lockout circuit cannot be
reactivated by adjusting the thermostat. To reset the crankcase heater lockout, disconnect and then reconnect power to
unit.
C. Liquid Line Solenoid
To minimize refrigerant migration to the compressor during
the heat pump OFF cycle, the unit features a bi-flow liquid
line solenoid valve. The valve opens when the compressor is
energized, and closes when the compressor is deenergized. This
feature reduces compressor flooded starts, significantly increasing compressor life.
D. Accumulator
The unit accumulator controls the rate of liquid refrigerant
to the compressor during heat pump operation. The accumulator features a unique method for returning oil to the compressor.The oil return mechanism is external to the accumulator. The mixture of oil and refrigerant is metered to the
compressor by a brass orifice which is removable and cleanable. The oil return mechanism also contains a solenoid valve
that opens when the compressor is ON and closes when the
compressor is OFF. This keeps the liquid refrigerant stored
in the accumulator from draining to the compressor during
the heat pump OFF cycle, which further protects the compressor against flooded starts.
—13—
Fig. 12 — Cooling Cycle Charging Chart,
541A120
shutdown is caused by manual reset devices (including OPS
[oil pressure switch] and compressor circuit breaker protection). To restart the unit when IP, HPS, or LCS has tripped
(after device has reset automatically), open and then close the
thermostat contacts. Opening and then closing thermostat contacts interrupts and restores 24-v power to the compressor
lockout (CLO), which resets the circuit.
It is necessary to manually reset the compressor circuit breaker
and OPS at the unit if either of these safeties should shut
down the unit.
IMPORTANT: If OPS trips, it must be reset first before mak-
ing and breaking the thermostat contacts to reset CLO. If this
procedure is not followed, the CLO cannot reset.
X. CAUSES OF COMPLETE UNIT SHUTDOWN:
• interruption of supplied power
• open compressor overtemperature protection (IP)
• compressor electrical overload protection (CB)
• open high-pressure or loss-of-charge safety switches
• open oil pressure switch
• open crankcase heater lockout (CLO2)
• open control circuit fuse (FU1 or FU2)
SERVICE
I. COMPRESSOR REMOVAL
See Table 1 for compressor information and Fig. 2 for component location. Follow safety codes and wear safety glasses
and work gloves.
1. Shut off power to unit. Remove unit access panel (front
of unit).
2. Recover refrigerant from system using refrigerant
recovery methods described in Training booklet GTAC
II, Module 5, and in accordance with local and national standards.
3. Disconnect compressor wiring at compressor terminal
box.
4. Remove bolts from suction and discharge service valves.
5. Remove 2 bolts and 2 screws from compressor mounting plate.
Fig. 13 — Cooling Cycle Charging Chart,
541A180
E. Oil Charge (Table 1)
Allow unit to run for about 20 minutes. Stop unit and check
compressor oil level. Add oil only if necessary to bring oil into
view in sight glass. Refer to Preliminary Oil Charge section
on page 12. Use only approved compressor oil.
F. Check Operation
Ensure operation of all safety controls. Replace all service panels. Be sure that control panel cover is closed tightly.
IX. RESTART
Manual reset of the 24-v control circuit is necessary if unit
shutdown is caused by automatic reset devices (including IP
[internal compressor overcurrent protection], HPS [highpressure switch], and LCS [loss-of-charge switch]) or if
—14—
CAUTION:
compressor may cause higher levels of vibration when
unit is restored to service.
6. Remove crankcase heater from compressor base.
7. Remove compressor from unit.
8. Remove compressor holddown bolts and lift compressor off mounting plate.
9. Clean system. Add new liquid line filter drier.
10. Install new compressor on compressor mounting plate
and position in unit. Connect suction and discharge lines
to compressor.Secure mounting plate with compressor
to unit. Ensure that compressor holddown bolts are in
place. Connect wiring. Install crankcase heater.
11. Evacuate and recharge unit.
12. Restore unit power.
Excessive movement of copper lines at
II. CRANKCASE HEATER
The crankcase heater prevents refrigerant migration and compressor oil dilution during shutdown when compressor is not
operating.
Close both compressor service valves when crankcase heater
is deenergized for more than 6 hours.
III. OUTDOOR UNIT FANS
Each fan is supported by a formed-wire mount bolted to the
fan deck and covered with a wire guard. The exposed end of
the motor shaft is covered with a rubber boot. In case a fan
motor must be repaired or replaced, be sure the rubber boot
is put back on when the fan is reinstalled and be sure the fan
guard is in place before starting the unit. Figure 14 shows
the proper position of the mounted fan.
IV. LUBRICATION
A. Fan Motors
Fan motors have permanently sealed bearings. No further lubrication is required.
B. Compressor
Compressor has its own oil supply. Loss of oil due to a leak in
the system should be the only reason for adding oil after the
system has been in operation. See Start-Up, Preliminary Oil
Charge.
Fig. 14 — Outdoor Unit Fan
V. CLEANING COILS
The coils can be cleaned with a vacuum cleaner, washed out
with low velocity water, blown out with compressed air, or
brushed (do not use wire brush). Fan motors are dripproof
but not waterproof. Do not use acid cleaners.
Clean coil annually or as required by location or outdoor air
conditions. Inspect coil monthly and clean as required. Fins
are not continuous through coil sections. Dirt and debris may
pass through first section, become trapped between the 2 rows
of fins (541A120) or 3 rows of fins (541A180), and restrict condenser airflow. Use a flashlight to determine if dirt or debris
has collected between coil sections.
Clean coils as follows:
1. Turn off unit power.
2. Remove screws holding rear corner posts and top cover
in place. Pivot top cover up 12 to 18 in. and support with
a board or other adequate rigid support. See Fig. 15.
3. Remove clips securing tube sheets together at the returnbend end of the coil. Carefully spread the ends of
the coil rows apart by moving the outer sections. See
Fig. 16.
4. Using a water hose or other suitable equipment, flush
down between the sections of coil to remove dirt and
debris.
5. Clean the remaining surfaces in the normal manner.
6. Reposition outer coil sections. Reinstall clips which secure tube sheets, and replace top cover and rear corner
posts.
7. Restore unit power.
Fig. 15 — Pivot and Support Top Cover
Fig. 16 — Coil Cleaning (541A120 Shown)
—15—
—16—
TROUBLESHOOTING CHART — HEATING CYCLE
LEGEND
CCH — Crankcase Heater
N.C. — Normally Closed
NOTE: See Fig. 17 for diagram showing
heating cycle operation.
—17—
TROUBLESHOOTING CHART — COOLING CYCLE
LEGEND
CCH — Crankcase Heater
TXV — Thermostatic Expansion Valve
NOTE: See Fig. 18 for diagram showing cooling cycle operation.
1. Hotgas from compressor flows through the reversing (4-way) valve
and is directed to the indoor coil header.At the header refrigerant
is directed to the indoor coil where it is condensed and subcooled
and then exits through the indoor coil check valve to the liquid
line. (The TXVs stop the refrigerant flow during the heating cycle.)
2. The refrigerant then feeds the outdoor coil by way of filter-drier, a
distribution manifold, and then through capillary tubes on each
circuit.
LEGEND
TXV — Thermostatic Expansion Valve
NOTES:
1. Check valves are designated ‘‘A’’ through ‘‘D.’’
2. Illustrations are typical and do not portray exact coil circuiting.
3. Check valve positions: open, closed.
Fig. 17 — Typical Heat Pump Heating Operation Schematic
(541A120 Shown)
3. Eachcircuit evaporates the refrigerant and all the circuits are combined in the outdoor header (with some of the circuits flowing through
the check valve ‘‘A’’).
4. The refrigerant then flows through the reversing (4-way) valve,
accumulator and back to the compressor.
—18—
1. Hotgas from compressor flows through the reversing (4-way) valve
and is directed to the outdoor coil header.At the outdoor coil it is
condensed and subcooled through converging circuits.
2. Checkvalve ‘‘A’’ directs all hot gas flow into circuits in bottom face
of outdoor coil. Refrigerant condenses in these circuits and then
exits into an intermediary collection header.
3. Refrigerant is directed from intermediary header to circuits in
upper face where further condensing is accomplished.
4. Refrigerant exits upper coil section into the top half of the vapor
header (above check valve ‘‘A’’) and is then redirected to a final
(subcooling) pass in center of coil face (120) or exits header via
outlet tube (180).
LEGEND
TXV — Thermostatic Expansion Valve
NOTES:
1. Check valves are designated ‘‘A’’ through ‘‘D.’’
2. Illustrations are typical and do not portray exact coil circuiting.
3. Check valve positions: open, closed.
Fig. 18 — Typical Heat Pump Cooling Operation Schematic
(541A120 Shown)
5. Refrigerant leaves the outdoor coil by way of check valve ‘‘B’’ to
the liquid line.
6. The refrigerant then flows through the filter drier and feeds the
indoor coil by way of the TXV and feeder valves.
7. Each circuit evaporates the refrigerant and the circuits are combined in the indoor coil header.
8. The refrigerant then flows through the reversing (4-way) valve,
accumulator and back to the compressor.
—19—
Copyright 1998 Bryant Heating & Cooling Systems CATALOG NO. 5354-100
START-UP CHECKLIST
A. Preliminary Information
OUTDOOR UNIT: MODEL NO.
INDOOR UNIT: MODEL NO.
ADDITIONAL ACCESSORIES
SERIAL NO.:
SERIAL NO.:
B. Pre-Start-Up
OUTDOOR UNIT
IS THERE ANY SHIPPING DAMAGE? (Y/N)
IF SO, WHERE:
WILL THIS DAMAGE PREVENT UNIT START-UP? (Y/N)
CHECK POWER SUPPLY. DOES IT AGREE WITH UNIT? (Y/N)
HAS THE GROUND WIRE BEEN CONNECTED? (Y/N)
HAS THE CIRCUIT PROTECTION BEEN SIZED AND INSTALLED PROPERLY? (Y/N)
ARE THE POWER WIRES TO THE UNIT SIZED AND INSTALLED PROPERLY? (Y/N)
HAVE COMPRESSOR HOLDDOWN BOLTS BEEN LOOSENED (Snubber washers are snug, but not tight)?
(Y/N)
CONTROLS
ARE THERMOSTAT AND INDOOR FAN CONTROL WIRING
CONNECTIONS MADE AND CHECKED? (Y/N)
ARE ALL WIRING TERMINALS (including main power supply) TIGHT? (Y/N)
HAS CRANKCASE HEATER BEEN ENERGIZED FOR 24 HOURS? (Y/N)
INDOOR UNIT
HAS WATER BEEN PLACED IN DRAIN PAN TO CONFIRM PROPER DRAINAGE? (Y/N)
ARE PROPER AIR FILTERS IN PLACE? (Y/N)
HAVE FAN AND MOTOR PULLEYS BEEN CHECKED FOR PROPER ALIGNMENT? (Y/N)
DO THE FAN BELTS HAVE PROPER TENSION? (Y/N)
HAS CORRECT FAN ROTATION BEEN CONFIRMED? (Y/N)
PIPING
HAVE LEAK CHECKS BEEN MADE AT COMPRESSOR, OUTDOOR UNIT, INDOOR UNIT,
TXVs (Thermostatic Expansion Valves), SOLENOID VALVES, FILTER DRIERS, AND FUSIBLE
PLUGS WITH A LEAK DETECTOR? (Y/N)
LOCATE, REPAIR, AND REPORT ANY LEAKS.
HAVE ALL COMPRESSOR SERVICE VALVES BEEN FULLY OPENED (BACKSEATED)? (Y/N)
HAS LIQUID LINE SERVICE VALVE BEEN OPENED? (Y/N)
IS THE OIL LEVEL IN COMPRESSOR CRANKCASE VISIBLE IN THE COMPRESSOR SIGHT GLASS?
(Y/N)
CHECK VOLTAGE IMBALANCE
LINE-TO-LINE VOLTS: AB
(AB + AC + BC)/3 = AVERAGE VOLTAGE =
MAXIMUM DEVIATION FROM AVERAGE VOLTAGE =
VOLTAGE IMBALANCE = 100 X (MAX DEVIATION)/(AVERAGE VOLTAGE) =
IF OVER 2% VOLTAGE IMBALANCE, DO NOT ATTEMPT TO START SYSTEM!
CALL LOCAL POWER COMPANY FOR ASSISTANCE.
VAC VBC V
V
V
CL-1
%
C. Start-Up
CHECK INDOOR FAN SPEED AND RECORD.
CHECK OUTDOOR FAN SPEED AND RECORD.
AFTER AT LEAST 10 MINUTES RUNNING TIME, RECORD THE FOLLOWING MEASUREMENTS:
COOLING HEATING
OIL PRESSURE
SUCTION PRESSURE
SUCTION LINE TEMP
DISCHARGE PRESSURE
DISCHARGE LINE TEMP
ENTERING OUTDOOR AIR TEMP
LEAVING OUTDOOR AIR TEMP
INDOOR ENTERING-AIR DB (dry bulb) TEMP
INDOOR ENTERING-AIR WB (wet bulb) TEMP
INDOOR LEAVING-AIR DB TEMP
INDOOR LEAVING-AIR WB TEMP
COMPRESSOR AMPS (L1/L2/L3) / / / /
CHECK THE COMPRESSOR OIL LEVEL SIGHT GLASSES; ARE THE SIGHT GLASSES SHOWING
OIL LEVEL IN VIEW? (Y/N)
NOTES:
CUT ALONG DOTTED LINE CUT ALONG DOTTED LINE
Copyright 1998 Bryant Heating & Cooling Systems CATALOG NO. 5354-100
CL-2
----------------------------------------------------------------------------------------
Loading...