Carrier ROOMTOP 50AH024 Dimensions and installation guide

Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
PC 111 Catalog No. 535-00076 Printed in U.S.A. Form 50AH-12SI Pg 1 8-02 Replaces: 50AH-9SI
Book 1 4
Ta b 2 b 7 a
Installation, Start-Up, and
Service Instructions
CONTENTS
SAFETY CONSIDERATIONS . . . . . . . . . . . . . . . . . . . . . . 1
GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
Step 1 — Receive and Inspect Unit . . . . . . . . . . . . . . . 1
Step 2 — Protect Unit from Damage . . . . . . . . . . . . . . 1
Step 3 — Provide Unit Support . . . . . . . . . . . . . . . . . . . 1
Step 4 — Rig and Place Unit . . . . . . . . . . . . . . . . . . . . . 4
Step 5 — Make Piping Connections . . . . . . . . . . . . . . 4
Step 6 — Install Ductwork . . . . . . . . . . . . . . . . . . . . . . . . 4
Step 7 — Make Electrical Connections . . . . . . . . . . . 4
Splitting Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Field Control Wiring. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Thermostat Wire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Step 8 — Adjust Fan Speed . . . . . . . . . . . . . . . . . . . . . . 5
START-UP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6,7
SERVICE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7,8
SAFETY CONSIDERATIONS
Installing and servicing air-conditioning equipment can be
hazardous due to system pressure and electrical components.
Only trained and qualified service personnel should install,
repair, or service air-conditioning equipment.
Untrained personnel can perform basic maintenance func-
tions such as cleaning coils and filters and replacing filters. All
other operations should be performed by trained service per-
sonnel. When working on air-conditioning equipment, observe
precautions in the literature and on tags and labels attached to
unit.
Follow all safety codes. Wear safety glasses and work
gloves. Use quenching cloth for unbrazing operations. Have
fire extinguisher available.
NOTE: Ensure voltage on unit agrees with voltage listed on
the unit rating plate.
GENERAL
The 50AH024,036,048, and 060 units are single-package,
indoor, horizontally mounted air conditioners of 2, 3, 4 and
5 tons capacity, respectively. The 50AH units are ASHRAE
(American Society of Heating, Refrigeration and Air Condi-
tioning Engineers) 90.1 compliant.
These units can be mounted as factory-shipped single-
package units or can be separated and mounted as a split
system. If unit is split, the condenser section can be mounted
horizontally.
All units are designed to be ducted on both the condenser
and evaporator sides. Centrifugal blowers are used to ensure
quiet air delivery to the conditioned space. Sound level
requirements should be determined before final unit installa-
tion site is chosen.
Unit servicing is relatively simple since access to the con-
denser and evaporator motors, blowers, belt, and pulley is
gained through removable swing doors located on bottom of
unit. These doors may also be used for cleaning of condenser
coils. Unit side panels provide access to control box and pres-
sure switches.
Refrigeration cycle components (e.g., compressor, filter
drier, etc.) can be serviced upon removal of the base unit from
the space.
INSTALLATION
The 50AH units are intended for indoor installation only.
Step 1 — Receive and Inspect Unit — Unpack and
check unit against shipping order. Inspect carefully for
concealed shipping damage. If unit is damaged or incomplete,
file claim with transportation company and advise Carrier
immediately.
Step 2 — Protect Unit from Damage — To main-
tain warranty, unit must be protected against theft and vandal-
ism and stored indoors at all times.
Step 3 — Provide Unit Support — Refer to Fig. 1
and 2 for unit dimensions and component locations. Refer to
Table 1 for unit sizes and weights.
Each unit requires the following field-supplied items:
4 — threaded suspension rods (3/8-in.-16 SAE Grade 1
minimum)
4—washers
4 — locknuts
Install the 4 field-supplied rods by suspending them from a
suitable ceiling support. Locate rods to mate with 4 outside cor-
ner rigging holes shown in Fig. 1 and 3.
The ceiling and ceiling supports of existing buildings may
require reinforcements; follow all applicable codes.
Before performing service or maintenance operations on
unit, turn off main power switch to unit. Electrical shock
can cause personal injury.
Determine building alterations required to run piping, wir-
ing, and ductwork. Follow dimensional drawings carefully
for ductwork, piping locations, electrical wiring, and over-
all unit dimensions. Read all installation instructions before
starting installation.
50AH024-060
Single-Package Cooling Units

2
Table 1 — Physical Data
LEGEND
*Shipping weights include base unit plus packaging.
†If components are to be split, additional refrigerant will be needed. Refer to Fig. 4-7
for charging charts.
**Two-speed motor.
††Use Type L copper only.
NOTE: If components are to be split, the maximum length of refrigerant tubing to be
used is 50 equivalent ft, assuming components will be installed in same horizontal
plane. If components are not to be installed in same horizontal plane, contact your
Carrier representative for more information. For additional piping information, refer to
Carrier System Design Manual, Part 3.
UNIT 50AH 024 036 048 060
SHIPPING WEIGHT (lb)* 560 590 690 700
OPERATING WEIGHT (lb)
Base Unit, Evap/Condenser Section 450, 193/256 480, 206/274 580, 250/330 590, 254/336
COMPRESSOR — TYPE Scroll
Quantity...Model (1)...ZR23 (1)...ZR34 (1)...SR48 (1)...ZR57
Oil (oz) 24 42 70 54
HPS Setting (psig)
Cutout 426 ± 7
Reset 320 ± 20
LPS Setting (psig)
Cutout 27 ± 4
Reset 67 ± 7
REFRIGERANT TYPE R-22
Operating Charge (lb)† 5.4 5.5 7.4 7.6
CONDENSATE DRAIN CONNECTION
Size (in.)...Type 3/4...FPT
CONDENSER COIL Copper Tubes — Aluminum Fins
Size (L x H) (in.) 40 x 15 40 x 16 40 x 22
Number of Rows...Fins/in. 4...13.6 4...17 4...13.6
CONDENSER FAN Centrifugal — Direct Drive Centrifugal — Belt Drive
Nominal Cfm 1350 1350 2250 2450
Maximum Rpm 1100 1500
Blower Size (in.) 12 x 6 12 x 9
Pulley Pitch Diameter (in.)
Blower None 5.0 6.0 6.0
Motor (Variable) None 2.4-3.4 1.9-2.9 2.4-3.4
Motor Hp 1/23/411
1/2
Motor Rpm 825 1725 1725 1725
EVAPORATOR COIL Copper Tubes — Aluminum Fins
Size (L x H) (in.) 34 x 15 34 x 16 34 x 22
Number of Rows...Fins/in. 4...14.4 4...15 4...14.4
EVAPORATOR AIR FAN (Standard) Centrifugal — Direct Drive
Nominal Cfm 800 1200 1600 2000
Max Rpm 1100 1150 900/1050**
Blower Size (in.) 10 x 5 10 x 6 10 x 6
Motor Hp (Rpm) 1/6(850) 1/2(1075) 3/4(1050)
EVAPORATOR AIR FAN (Optional)
Not
Available
Centrifugal Belt Drive
Nominal Cfm 1600 2000
Max Rpm 1300
Blower Size (in.) 10 x 8
Motor Hp 11/2
Motor Rpm 1725
Pulley Pitch Diameter (in.)
Blower 4.2
Motor (Variable) 2.4-3.4
INDOOR-AIR FILTERS Factory-Supplied Cleanable Type
Number...Size (in.) 1...14 x 34 x 1 1...21 x 34 x 1
INTERCONNECTING TUBING SIZE (in.)††
Hot Gas 1/21/21/21/2
Liquid 3/83/83/83/8
HPS — High-Pressure Switch
LPS — Low-Pressure Switch
DIMENSIONS (ft-in.)
UNIT
50AH ABCDE
024 2-5 2-15/81- 53/41-2 1-1
036 2-43/42-2 1- 53/41-2 1-1
048 2-5 2-3 1-115/81-87/81-77/8
060 2-43/42-23/41-115/81-77/81-77/8
LEGEND
Center of Gravity
Direction of Airflow
Fig. 1 — Dimensions

3
CONTROL BOX ACCESS PANEL,
COMPRESSOR, LOW- AND HIGH-
PRESSURE SWITCHES AND
SERVICE PORT CONNECTION
ACCESS
JUNCTION BOX
CONDENSER
SIDE ACCESS
PANEL
CONDENSER MOTOR
AND BLOWER ACCESS-ALSO
PROVIDES ACCESS FOR
CLEANING CONDENSER COIL
FILTER
EVAPORATOR MOTOR
AND BLOWER ACCESS-ALSO
PROVIDES ACCESS FOR
CLEANING EVAPORATOR
FILTER DRIER AND
CAPILLARY TUBE ACCESS
ACCESS DOORS
EVAPORATOR MOTOR
CONDENSER MOTOR AND
BLOWER ASSEMBLY
CONTROL BOX
FILTER
DRIER
UNIT WITH FILTER
REMOVED
Fig. 3 — Rigging Details
Fig. 2 — Component Locations
CENTER OF GRAVITY
NOTE: Fasten threaded rods through holes in end frames as shown.
Use 2 rods on each side of unit for a total of 4.
UNIT 50AH DIMENSIONS (in.)
AB
024 29.0 25.6
036 28.8 26.0
048 29.0 27.0
060 28.8 26.8
All panels must be in place when rigging.

4
Step 4 — Rig and Place Unit — Move and store unit
in horizontal position. Provide space around unit for service,
filter access, ductwork, and overhead clearance as indicated in
Fig. 1.
Using suitable hydraulic lift source, raise unit up to meet
bottom of the 4 threaded rods suspended from ceiling. Center
unit so that the 4 threaded rods can be easily inserted into
the factory-drilled holes at each end. Refer to Fig. 3 for rigging
details.
Apply washers and locknuts on ends of each of the 4 rods.
Tighten locknuts sufficiently so that unit weight is support-
ed entirely by the 4 rods. Level unit within the space by adjust-
ing locknuts.
NOTE: The 2 factory-drilled holes in the middle of unit can be
used for support if a split system application is desired. If
required, an accessory vibration isolator package is available
for use to minimize vibration that may be transmitted to build-
ing structure.
NOTE: For split systems, 8 suspension rods are required.
Refer to Splitting Systems section below.
Step 5 — Make Piping Connections — Two 3/4-in.
pipe thread condensate drain connections are provided below
the evaporator coil. One 3/4-in. pipe thread connection is pro-
vided for condenser coil washdown. One of the evaporator
drains is plugged at the factory; plug must be removed when
making field connections. The condenser washdown pan is
plugged at the factory. This drain is to be used only when con-
denser coil is being cleaned; plug must be replaced when
cleaning is completed.
Step 6 — Install Ductwork — Use flexible ductwork
to attach duct to unit and to help control transmission of vibra-
tions to building structures. Attach ductwork to the return and
supply ends of both coils.
If unit is located with condenser close to outside of building,
install a field-supplied rainhood. Hood intake dimensions
should be same as condenser return-air dimensions. In addi-
tion, install a triple-layer bird screen over rainhood intake to
eliminate possibility of insects, birds, water, or debris from
entering unit. Ensure hood and/or louvers are installed correct-
ly to avoid condenser air recirculation.
Step 7 — Make Electrical Connections — Con-
nect power wiring to junction box located on unit side near
control box access panel. All wiring must comply
with National Electrical Code (NEC) and all local code
requirements.
Operating voltage to compressor must be within voltage
range as indicated on unit nameplate. On 3-phase units, volt-
ages between phases must be balanced within 2% and current
must be balanced within 10%. Contact local power company
for correction of improper voltage or phase imbalance. Unit
failure as a result of operation on improper line voltage or ex-
cessive phase imbalance constitutes abuse and may cause dam-
age to electrical components. Such operation would invalidate
any applicable Carrier warranty.
Install a fused disconnect per NEC on the 5-ton (060)
230-1-60 unit. Refer to unit nameplate and Table 2 for fuse
sizes and wire amperages for all units.
Splitting Systems — The 50AH roomtop units may be
split into 2 sections, if desired, with condensing section
mounted remotely either horizontally or vertically. If sections
are installed in same horizontal plane they may be separated by
up to 50 equivalent ft of tubing. Use type L copper or better.
Condensing section must be located in same plane as, or
above, evaporator section to maintain the liquid refrigerant seal
at the expansion device. This permits expansion device to feed
liquid refrigerant to evaporator coil properly. To split sections
(some of the following steps may be eliminated depending on
particular application):
1. Disconnect all electrical power to unit.
2. Remove 4 bolts connecting the 2 sections.
3. Remove top panels from each section.
4. Recover the refrigerant from the system using both the
high- and low-pressure ports.
5. Cut refrigerant piping in the evaporator section just inside
the partition between the 2 sections.
Table 2 — Electrical Data
LEGEND *Optional evaporator-fan motor nameplate data.
IMPORTANT: Unit must be level to operate properly.
UNIT
50AH
V-P H
(60 Hz)
VOLTAGE RANGE COMPRESSOR FAN MOTORS POWER SUPPLY
Evaporator Condenser Min Ckt
Amps
MOCP
Amps
Min Max RLA LRA Hp FLA Hp FLA
024 230-1 207 254 11.4 56 .17 1.10 .50 3.40 19.0 25
036
230-1 207 254 17.2 96 .50 3.20 .75 6.06 29.5 40
208/230-3 187 254 10.3 77 .50 3.20 .75 3.93 19.9 25
460-3 414 508 5.1 40 .50 1.50 .75 1.97 8.9 15
048
230-1 207 254 24.4 150 .75 4.00 1.0 8.35 42.9 60
208/230-3 187 254 15.5 105 .75 4.00 1.0 3.93 27.3 35
460-3 414 508 7.4 55 .75 2.15 1.0 1.97 13.4 20
048* 208/230-3 187 254 15.5 105 1.5 5.60 1.0 3.93 28.9 35
460-3 414 508 7.4 55 1.5 2.80 1.0 1.97 16.3 20
060
230-1 207 254 28.8 169 .75 4.00 1.5 9.50 49.5 60
208/230-3 187 254 17.3 123 .75 4.00 1.5 4.82 30.4 40
460-3 414 508 9.0 62 .75 2.15 1.5 2.41 15.8 20
060* 208/230-3 187 254 17.3 123 1.5 5.60 1.5 4.82 32.0 40
460-3 414 508 9.0 62 1.5 2.80 1.5 2.41 16.0 20
HACR — Heating, Air Conditioning, and Refrigeration
Hp — Horsepower
FLA — Full Load Amps
LRA — Locked Rotor Amps
MOCP — Maximum Overcurrent Protection (HACR breaker)
RLA — Rated Load Amps

5
6. Unsweat the cut portions of the refrigerant piping in
evaporator section at the closest bell joint. The bell joints
are used to connect field-supplied refrigerant piping to
evaporator section. Cut and braze a length of tubing to ex-
tend refrigerant piping outside the evaporator section.
NEC disconnects are required if units are not installed
within line of sight of each other.
7. Cut condenser-fan motor wiring at the partitions separat-
ing condenser and evaporator sections.
8. In the condenser section, install a junction box adjacent to
the D-shaped grommet.
9. Install evaporator and condensing sections in desired
locations. Refer to Steps 10-12 below.
10. Use appropriate length of no. 16 American Wire Gage
(AWG) (minimum), 4/64-in. insulated copper wire to re-
connect cut condenser-fan motor wires. Make connec-
tions in junction boxes installed in earlier steps. Follow
all applicable electrical codes.
11. Use sufficient length of refrigerant piping to reconnect
piping cut in previous step. Refer to Carrier System
Design Manual, Part 3, for additional piping data. Liquid
line tubing is 3/8-in. OD copper tubing, and hot gas line is
1/2-in. OD copper tubing.
12. Replace top panels on each section.
13. Recharge unit with R-22 following Charging Charts
(Fig. 4-7) in these instructions.
After splitting sections, additional refrigerant must be added
to system to ensure proper refrigerant charge. The amount of
refrigerant to be added depends on length of tubing added to
system and operating temperatures of system. Refer to Carrier
System Design Manual, Chapter 3. Allow unit to operate at
least 10 minutes before adjusting refrigerant charge.
Since standard roomtop unit has negligible line losses, split-
ting the system can increase line loss and decrease system
capacity. Capacity reduction can be determined by referring to
Carrier System Design Manual.
Field Control Wiring — Install a Carrier-approved
accessory thermostat assembly according to installation
instructions provided by thermostat manufacturer. Locate
thermostat assembly on a solid wall in the conditioned space
away from drafts to sense average room temperature.
Using thermostat cable or equivalent single leads of no. 18
AWG colored wire, route cable or wire from the subbase termi-
nals, up and through connector on unit side (below power lead
junction box) and connect to low-voltage terminal block inside
the control box.
Thermostat Wire — Use 18 gage for 0-ft to 50-ft long
wires and 16 gage for 51- to 75-ft wire lengths.
Step 8 — Adjust Fan Speed — Adjust fan speed to
meet jobsite conditions. Refer to Tables 3-5 to determine fan
speed settings. See Service section of this document for
instructions to adjust fan speed.
EVAPORATOR-FAN MOTORS — The evaporator-fan mo-
tor factory speed setting is shown on label diagram affixed to
base unit. If other than factory setting is desired, refer to label
diagram for motor reconnection.
CONDENSER-FAN MOTORS — The condenser-fan mo-
tors on 50AH036-060 units are belt drive. The 50AH024 has a
direct-drive motor.
Table 3 — Evaporator-Fan Performance
LEGEND
*Standard direct drive indoor-fan motor (IFM). For optional belt drive
IFM performance, see Table 4.
NOTES:
1. Above fan performance is based on wet coil and deducted casing
losses, and clean factory-installed permanent cleanable filter.
2. Evaporator fans are direct drive (except 048, 060 optional indoor-
fan motor).
3. Interpolation is permissible, do not extrapolate.
Table 4 — Optional Belt-Drive
Evaporator-Fan Performance
NOTE: Pulley setting must be adjusted to limit cfm to 450 cfm/ton
maximum. Unit operation beyond that limit may result in blow-off and
condensate problems.
AIRFLOW
(cfm)
UNIT SIZE — 50AH
024 036 048* 060*
ESP Fan
kW ESP Fan kW ESP Fan kW ESP Fan kW
600 .60 .20 ———— ——
700 .54 .22 ———— ——
800 .43 .24 ———— ——
900 .29 .26 .69 .44 —— ——
1000 .11 .29 .57 .46 —— ——
1100 ——.42 .49 1.10 .45 1.11 .52
1200 ——.23 .52 1.01 .49 1.045 .55
1300 —— ——.90 .51 .97 .57
1400 —— ——.79 .55 .88 .59
1500 —— ——.67 .58 .78 .62
1600 —— ——.54 .61 .67 .64
1700 —— ——.39 .64 .53 .67
1800 —— ——.22 .67 .52 .70
1900 —— ——.03 .70 .40 .74
2000 — — —— —— .28 .78
ESP — External Static Pressure (in. wg)
kW — Total Fan Motor Power Input (kilowatts)
AIRFLOW
(cfm)
UNIT SIZE — 50AH
048 060
ESP Fan kW ESP Fan kW
1800 ————
1850 ————
1900 ————
1950 .81 1.03 ——
2000 .72 1.05 ——
2050 .63 1.07 ——
2100 .55 1.08 1.02 1.17
2150 .47 1.11 .93 1.21
2200 .42 1.14 .84 1.24
2250 .34 1.17 .75 1.27

6
Table 5 — Condenser-Fan Performance
LEGEND
kW — Total Fan Motor Power Input (kilowatts)
NOTES:
1. Above fan performance is based upon coil and deducted casing losses only.
2. External static pressure (ESP) is measured in inches water gage (in. wg).
3. Interpolation is permissible. Do not extrapolate.
4. Condenser fan on unit size 024 only, is direct drive.
5. Minimum one turn open of motor pulley is required on unit sizes 036 and 060.
6. Number of turns open applies to field setting of motor pulley.
7. Factory setting as follows: 036, 4 turns open; 048, 2 turns open; 060, 5 turns open.
8. Care should be taken when hoods and/or louvers are installed to avoid condenser air recirculation.
START-UP
Unit Preparation — Make sure unit has been installed in
accordance with installation instructions and applicable codes.
Compressor Mounting — Compressors are internally
spring mounted. Do not loosen or remove compressor hold-
down bolts.
Internal Wiring — Check all electrical connections in
unit control boxes and tighten as required.
Refrigerant Service Valves — Each unit system has
3 Schrader-type service ports, one on the suction line, one on
the compressor discharge line, and one for low-ambient damp-
er kit. Be sure that caps on the ports are tight. One Schrader-
type valve is located under both the high-pressure switch and
low-pressure switch.
Compressor Rotation — On 50AH036-060, 3-phase
units, it is important to be certain compressor is rotating in the
proper direction. To determine whether or not compressor is
rotating in the proper direction:
1. Connect service gages to suction and discharge pressure
fittings.
2. Energize the compressor.
3. The suction pressure should drop and the discharge pres-
sure should rise, as is normal on any start-up.
If the suction pressure does not drop and the discharge pres-
sure does not rise to normal levels:
1. Note that the condenser fan may also be rotating in the
wrong direction.
2. Turn off power to the unit and tag disconnect.
3. Reverse any two of the unit power leads.
4. Reapply power to the unit; remove tag.
5. Verify correct refrigerant pressures.
The suction and discharge pressure levels should move to
their normal start-up levels.
NOTE: When the compressor is rotating in the wrong direc-
tion, the unit will sound louder than normal and will not
provide cooling.
Cooling — To start unit, turn on main power supply. Set
system selector switch at COOL position and fan switch at
AUTO. position. Adjust thermostat to a setting below room
temperature. Compressor, condenser and evaporator motors
start on closure of contactors.
TO SHUT OFF UNIT — Set system selector switch at OFF
position or reset thermostat at a position above room tempera-
ture. Units are equipped with either Time Guard® II control
(50AH024,048,060 — single-phase only) or Cycle-LOC™
protective device (all other units).
UNIT
50AH
AIRFLOW
(cfm)
EXTERNAL STATIC PRESSURE (in. wg)
0.0 0.1 0.2 0.3 0.4 0.5 0.6
Turns kW Turns kW Turns kW Turns kW Turns kW Turns kW Turns kW
024
1525 Note 4 .66 ————————————
1475 ——Note 4 .64 ——————————
1400 — ———Note 4 .63 ————————
1350 — —————Note 4 .62 ——————
1300 — ———————Note 4 .62 ————
036
1650 2 .84 ————————————
1600 ——2.82——————————
1550 — ——— 2.80————————
1500 3 .72 ———— 2.781.84————
1450 4 .63 3 .70 ———— 2 .76 1 .83 ——
1400 ——4 .61 3 .68 —————— 1.81
1350 5 .51 ———— 3.67—— 2.73——
1300 ——5 .50 4 .57 —— 3.65—— 2.71
048
2700 2 .90 ————————————
2600 ——2.87——————————
2550 3 .81 ————————————
2450 ——3 .77 2 .83 1 .89 ——————
2350 — ————— 2.801.86————
2300 4 .68 —— 3.74———— 0.90——
2200 ——4.66———— 2 .77 1 .82 0 .86
060
3100 3 1.34 ————————————
3000 ——31.32——————————
2900 — ————— 21.39——————
2850 4 1.11 —— 31.24————————
2750 ——41.07———— 21.32————
2700 — ————— 31.17——————
2650 — ——————————— 11.37
2600 5 .95 —— 41.01———— 21.26——
2550 — ——————— 31.12————
2500 ——5.92——————————
2450 — ————— 4.97———— 21.21
2400 — ——— 5.90———— 31.08——

7
Time Guard® II control automatically prevents compressor
from restarting for at least 5 minutes after a shutdown, prevent-
ing short cycling of compressor if thermostat is rapidly
changed.
Cycle-LOC™ protective device shuts unit down on any
safety trip. The protective device causes an indicator light on
the thermostat to light upon safety trip. Be sure to check reason
for safety trip before restarting unit. Compressor restart is
accomplished by manual reset at the thermostat by turning the
selector switch to OFF and then to ON position.
SERVICE
Filters — Filters are cleanable and should be inspected and
cleaned at regular intervals monthly or as conditions require.
Filters can be washed with water or vacuumed as needed. They
are located in front of the evaporator coil and may be removed
by sliding them horizontally out to edge of unit. See Fig. 1 and
2. No tools are required for installation or removal of filters.
Condenser Coil — The condenser coil is accessible
through the bottom access door marked condenser section, or
through side access panel on condenser section, or through side
access panel on condenser section. Use a stiff brush when
cleaning coil. Be careful not to bend aluminum fins.
Connect the condenser washdown pan drain connection
(3/4-in. FPT) to the building drain using a 3/4-in. MPT hose. En-
tering through unit bottom condenser access door, use a water
hose or other suitable equipment to flush out dirt and wash
down coil. Be careful not to force water spillage out of con-
denser washdown pan.
Evaporator Coil — The evaporator coil is accessible for
cleaning through the bottom access door marked “Evaporator
Section.” When necessary, wash coil with a commercial clean-
er (Oakite 164) or dishwasher detergent using a pressurized
spray canister. Flush coil from return-air duct side and take
care not to get water in ductwork or unit insulation.
Condensate Drain — Clean and empty drain pan at
least once a year to prevent sludge build-up.
Lubrication — Lubrication of the condenser and evapora-
tor motors is not necessary since both are equipped with
permanently lubricated bearings. Do not oil.
Motor Speed Adjustment — Direct-drive evaporator
motors require no adjustment.
Unit 50AH024 Condenser Motor — Condenser
motor is direct drive, single speed and requires no adjust-
ment.
Unit 50AH036-060 Condenser Motor — All
50AH036-060 units contain belt-driven adjustable-pulley con-
denser fan systems. 50AH036 unit fan motors are shipped with
adjustable pulley at 4 turns open. All 50AH048 unit fan motors
are shipped with adjustable pulley 2 turns open and 50AH060
are shipped at 5 turns open, and can be adjusted to increase fan
speed.
Blower Wheel Servicing — In-space servicing is rec-
ommended for the evaporator and condenser blowers. Both are
removed by loosening and removing the 4 screws that hold
them in place. In both cases, the entire assembly is then moved
outside of the base unit. Once outside, the blower wheel and
condenser shaft bearings and/or evaporator motor can be
serviced.
Blower Belt Adjustment — Inspect blower belt for
wear, proper belt tension, and pulley alignment as conditions
require or at the beginning of each heating and air conditioning
season. Refer to Step 8 — Adjust Fan Speed on page 5 for ad-
justment and alignment procedures.
Control Box Side Access Panel — The control box
side access panel is held in place with 1/4-in. self-retaining fas-
teners. When these fasteners are pulled, the access panel can be
turned around 180 degrees so that its metal lip will line up with
the metal lip on bottom of unit. This enables the access panel
cover to hang down, exposing the base unit wiring diagram and
enabling the service person to work more freely.
Refrigerant Charge — Amount of refrigerant charge is
listed on unit nameplate (also refer to Table 1). Refer to Carrier
GTAC II; Module 5; Charging, Recovery, Recycling, and Rec-
lamation manual and the following procedure.
Unit panels must be in place when unit is operating during
charging procedure. Unit must operate for at least 10 minutes
before adjusting charge.
NO CHARGE — Use standard evacuating techniques. After
evacuating system, weigh in the specified amount of refriger-
ant. (Refer to Table 1.)
LOW CHARGE COOLING — Using Cooling Charging
Charts, Fig. 4-7, vary refrigerant until the conditions of the
appropriate chart are met. Note the charging charts are differ-
ent from type normally used. Charts are based on charging the
units to the correct superheat for the various operating condi-
tions. Accurate pressure gage and temperature sensing device
are required. Connect the pressure gage to the service port on
the suction line. Mount the temperature sensing device on the
suction line and insulate it so that surrounding ambient temper-
ature does not affect the reading. Indoor-air cfm must be within
the normal operating range of the unit.
TO USE COOLING CHARGING CHART — Take the ambi-
ent temperature and read the suction pressure gage. Refer to
appropriate chart to determine what suction temperature
should be. If suction temperature is high, add refrigerant. If
suction temperature is low, carefully recover some of the
charge. Recheck the suction pressure as charge is adjusted.
Example: (Fig. 5)
Ambient Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .85 F
Suction Pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 psig
Suction Temperature should be. . . . . . . . . . . . . . . . . . . . . . .47 F
(Suction Temperature may vary ± 5 F.)
ELECTRIC SHOCK HAZARD
Open all remote disconnects and tag before
servicing this equipment.
IMPORTANT: If repairs to refrigerant cycle compo-
nents (e.g., compressor, filter drier, etc.) are required,
recover all refrigerant from the system by using both
high- and low-pressure ports. Then remove base unit
from the space.

Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
PC 111 Catalog No. 535-00076 Printed in U.S.A. Form 50AH-12SI Pg 8 8-02 Replaces: 50AH-9SI
Book 1 4
Ta b 2 b 7 a
Copyright 2002 Carrier Corporation
Fig. 4 — Charging Chart — 50AH024 Fig. 6 — Charging Chart —50AH048
Fig. 5 — Charging Chart — 50AH036 Fig. 7 — Charging Chart — 50AH060