Carrier 38AD Dimensions and installation guide

Condensing Units
Air-Cooled — Remote
INSTALLATION
Lifting Unit — Do not sling unskidded unit. Use
spreader bars to prevent slings from damaging unit
panels. Do not roll unskidded unit on pipes or
rollers.
Skid Removal — Remove the 4 bolts holding top
frame in place and lift frame from unit.
Remove compressor compartment end panel.
Raise and block up compressor end of unit about
10 inches. Remove 4 bolts and nuts, 2 in end
corners and 2 where compressor and condenser
sections meet. Lower unit. Raise and block
opposite end. Remove remaining 2 bolts and nuts.
Position Unit so air flow is unrestricted for at least
2 ft on each side, 3 ft on each end, and for at least
5 ft above unit top. See Fig. 1.
Erect Unit using legs attached to unit base skid.
Block up or suspend unit. Bolt leg to each
corner of unit. Bolt 2 legs to bottom of unit where
compressor and coil sections meet. Lower unit.
Compressor Mounting — As shipped, compressor is
held tight by self-locking bolts.
BEFORE STARTING UNIT - Loosen self-locking
bolts until the flanged washer is still snug but can
be moved sidewise. Do not remove shipping bolts.
V KtGGiNG POINTS <4) HOLES
LEGEND
1 -3/8~>rs. ODE Suction Line Conn. 2-1/2-in. Oiaro Hote
5/8-in. ODE Liquid Line Conn. 7/8-in. Diem Hote
3/4-in. Thermostat Conn. 7/8-in. Diem Hote
D — l-T/4-in. Electrical Conn. 1-3/4-in. DiarrrHote
E — 3/4-in. Fan Coil Control Wire Conn. 7/8-in. Diam Hole
Certified dimension drawings are avaite&te on request.
Fig. 1 — Physical Data and Dimensions
© Carrier Corporation 1971
Form 38AD-4SI

Table 1 — Physical Data (60-Hz)
UNIT 38AD 012
014
016
OPER WT (lb)
770
805 970
REFRIGERANT
22 22
22
COMPRESSOR
Recip Hermetic 6 Cyl; 1750 Rpm
Model No. 06DD328
06DD537 06DD537
Oil (pts) Suniso 3GS
or Capella Bl
10
10
10
Crankcase Htr Watts
75
75
75
Unloader Setting
Load
70 ± 1 psig
70 ± 1 psig
70 ± 1 psig
Unload
60 ± 2 psig
60 ± 2 psig 60 i 2 psig
OUTDOOR AIR FANS
Axial
Flow; Direct Drive
No. ...Rpm 2...1085
2 ..1085
3...1120
Diam (in.)
22 22
22
Motor Hp (NEMA)
l / 2
%
l / 2
Nom Cfm Total
8800 8000
13,000
CONDENSER COIL
Face Area (sa ft)
Storage Cap. (lb)*
19 1 19.1
26.2
17.7
26.5
51
CONTROLS
Pressurestat Settings
High Cutout
400 ± 5 psig
400 ± 5 psig
364 ± 5 p s i g
Cut-In
300 ±20 psig
300 ± 5 psig
264 ± 15 psig
Low Cutout
29 ± 5 psig
29 ± 5 psig
29 ± 5 p sig
Cut-In
64 ± 10 psi g
64 + 10 psig
64 ± 5 psig
Fan-Cycling Thermo.
No. 2 Opens
Closes
60 ± 2 F
60 ± 2 F
70 F
65 ± 4 F
65 ± 4 F
75 F
No. 3 Opens
— -
57 F
Closes - -
62 F
FUSIBLE PLUG
200 F
200 F
200 F
*Storage capacity is with condenser 80% full of liquid R-22 at 130 F
for 38AD012 and 014, and 120 F for 38AD016.
Fan-Cycling Thermostat temperature sensing bulb
and coiled capillary are taped to compressor conduit
in compressor compartment for shipment. Carefully
remove tape and uncoil capillary. Route bulb and
capillary behind compressor and out of compressor
compartment thru space under right-hand condenser
coil. Do not kink or damage capillary or sensing bulb.
Position sensing bulb in inlet airstream. With
mounting clamp and hardware provided in parts
package, secure sensing bulb to lower tube sheet near
compressor so that it does not touch coil fins. Be sure
airstream across bulb is unrestricted and that bulb
does not receive direct sunlight.
Refrigerant Line Sizes will depend on length of piping
required between condensing unit and evaporator.
Consideration must be given to liquid lift and to
compressor oil return (see Table 2). Refer to Part 3 of
Carrier System Design Manual for design details and
line sizing.
Refer to Evaporator Installation Instructions for
additional information.
Refrigerant Drier and Moisture Indicator — A filter-
drier and a liquid-moisture indicator are shipped with
unit for field installation (Table 2). Install according
to manufacturer’s instructions.
Receiver — No receiver is provided with unit. It is
recommended that one not be used.
Piping Procedure — Do not remove plastic dust plugs
from suction and liquid line stub in compressor
compartment until piping connections are ready to be
made. Pass nitrogen or other inert gas thru piping
while brazing, to prevent formation of copper oxide.
Install field-supplied thermostatic expansion
valve(s) to evaporator section. If two thermostatic
expansion valves are installed for two-step cooling,
install field-supplied liquid line solenoid valve
ahead of second expansion valve.
Install filter-drier in the common liquid line just
ahead of both expansion valves.
Table 2 — Liquid Line Data
UNIT
MODEL
38AD
MAX
ALLOW.
LIQUID
LIFT
(ft)
LIQUID LINE
Max Allow.
Press. Drop
(psi)
Max Allow.
T emp
Loss
(F)
Fi Iter-Drier
and Sight Glass
Flare Conn.*
(in.)
012
75 7
1.5
%
014 50 7
1.5
5 /»
016
78 7
1.0
%
*lnlet and outlet
Safety Relief — A fusible plug is located on com¬
pressor crankcase (Fig. 2). Do not cap this plug.
If local code requires additional safety devices,
install them as directed.
Fig. 2 — Tee Connection
Power Wiring — Unit is factory wired for voltage
shown on nameplate. 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, especially if
disconnect is not visible from unit. Disconnect
switch, fuses, and field wiring must comply with
National Electrical Code and local requirements.
Route power wires thru openings in unit
bottom panel to connections in unit control box as
shown on unit label diagram and Fig. 3. Unit must
be grounded.
Affix crankcase heater power warning sticker to
unit disconnect switch.
Fig. 3 — Main Power Supply

Table 3 — Electrical Data (60-Hz)
V/PH
MWA ICF FU
COMPR
Norn
Min-Max
FLA
LRA
410
208/3
187-229
68 198 80
49.3
191
510
230/3
198-254 62 179 70
44 3 172
U 1 z
610
460/3
414-506
31 89 35
22.2 86
no
575/3
518-632 24
71
30 17.9
69
400 208/3 187-229 86 184 100
63.6
266
3 2
500 230/3 198-254
78 166 90
57. % 3 2
600 460/3
414-506
39 123 45
28 6
120 1 6
100
575/3 518-632 32
99
35
22.9
96
1.0
fTjTSJ
208/3
187-229
86
184
100
64.0
266
3 2
Kin
230/3 198-254
78 166 90
58.0: Mii/240
3.2
K 11
460/3
414-506 39 123 45
29.0
120
1.6
Euj
575/3
518-632 32
99
40 23.0
96 1 0
Values are for part-winding start.
FLA — Full Load Amps
FU — Fuse (max allowable amps; dual element)
ICF — Max Instantaneous Current Flow (during start-up; sum of
compressor LRA plus F LA of all other motors in the unit)
LRA — Locked Rotor Amps
MWA — Minimum Wire Amps per NEC
*Units 38AD012 and 014 have two; unit 38AD016 has three.
Control Circuit Wiring — Control voltage is 115
volts. Install a field-supplied 115-volt thermostat
with minimum rating of one amp (Fig. 4).
If a 24-volt thermostat assembly is to be used,
install Accessory Relay Package 38AD900001 (Fig.
5) above terminal board (TB2) in unit control box.
Three field-supplied no. 10 sheet metal screws are
required. Control box back panel holes are
predrilled.
115-Volt Accessories
Winter Start Control (if required) — Reset and
relocate the unit low pressurestat and install
field-supplied defrost thermostat (Carrier part no.
50BB900001).
LOW PRESSURESTAT - Isolate compressor by
frontseating discharge and suction service valves.
Relieve compressor pressure. Reset the unit low
pressurestat to 5 psig. Disconnect the low pressure¬
stat capillary from compressor crankcase and cap
the unused 1 /4-in. flare fitting on the compressor.
Backseat liquid line service valve to shut service
port. Connect the low pressurestat capillary to the
liquid line service valve service port. Open service
port and compressor service valves.
DEFROST THERMOSTAT - Control is not water¬
proof or moisture resistant. Protect control against
direct contact with moisture or condensation of
moisture on switch insulator. Mount control with
approximately 2 in. of top of thermostat capillary
passing thru lower part of evaporator coil and with
remainder of capillary inserted between fins on
entering air side of coil. Connect thermostat
electrical contacts into indoor cooling thermostat
circuit or in series with compressor holding coil.
NOTE: Defrost thermostat must be used on all
systems operating with outdoor temperatures
below 45 F.
24-Volt Accessories
Motormaster® (32 Series) Head Pressure Controller
— Refer to Installation Instruction shipped with
this accessory plus the following information.
Control box and sensor (thermistor) location
is shown in Fig. 6.
Electrical connections are shown in Fig. 7.
Refer to unit label diagram as required.
Fig. 6 — Motormaster® Control Box and
Sensor Location
3
473

Fig. 7 — Motormaster® Electrical Connections
On 208-, 230- and 460-volt units, outdoor fan
motor no. 1 (OFMi) is suitable for use with Motor-
mastei® without modification.
On 575-volt units, install a field-supplied 1 kva
transformer (Carrier part no. HT01AH959) and
replace 575-volt outdoor fan motor no. 1 with
230-1-60 motor (Carrier part no. HC44VL851 or
HC44VE851) and add field-supplied capacitor
(Carrier part no. HC96FH007).
INITIAL START-UP
Evacuate and Dehydrate the entire refrigerant
system by either of the methods described in the
Carrier Standard Service Techniques Manual,
Chapter 1, Section 1-7.
Leak Test the entire refrigerant system by the
pressure method described in the Carrier Standard
Service Techniques Manual, Chapter 1, Section 1-6.
Use R-22 at approximately 25 psig backed up with
an inert gas to a total pressure not to exceed 245
psig.
Before Starting Unit check the following:
1. Compressor oil level must be at least within
sight in each compressor crankcase. Add oil if
necessary.
2. Compressor hold-down bolts must be snug but
not tight. Refer to Installation Instructions or
tag on compressor foot.
3. All internal wiring connections must be tight;
all barriers and covers must be in place.
4. Electrical power source must agree with unit
nameplate rating.
5. All service valves must be open.
6. Crankcase heater must be firmly locked into
the compressor crankcase.
Energize Branch Circuit — Set room thermostat
above ambient. Close field disconnect switch. Be
sure that compressor crankcase heaters are opera¬
ting. Allow crankcase heaters to operate a mini¬
mum of 24 hours before starting unit.
To Start Unit set room thermostat below ambient.
After starting unit there will be a delay of at least
15 seconds before compressor starts.
To Charge System — Add refrigerant to system
using weight method as described in Standard
Service Techniques Manual plus the following:
1. Before starting compressor, charge system with
initial charge for liquid seal (Table 4).
2. Start condensing and evaporator units and
charge to a clear sight glass using Charging by
Sight Glass procedure. Restrict air flow thru
condenser coil with a sheet of plywood or
cardboard to achieve condensing temperature
shown in Table 4.
3. Add additional refrigerant vapor as shown in
Table 4 to fill subcooler coils using Charging by
Weight Procedure.
After Charging System 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. If oil is added, run unit for
additional 10 minutes. Stop unit and check oil
level. If level is still low, add oil only after
determining that piping system is designed for
proper oil return and that the system is not leaking
oil. Check the operation of all safety controls.
Replace all service panels. Be sure that control
panel cover is closed tightly.
Table 4 — Charging Data (R-22)
UNIT
MODEL
38AD
REFRIG CHG (lb)
CONDENSING
TEMPERATURE
DURING
CHARGING
(F)
Initial
For
Liquid
Seal
Sub
Cool er*
012
10
3
130
014
13
2
130
016
14
6
120
*For maximum system capacity without receiver
NOTE:
Values shown do not include charge requirements for cooling
coils and system piping
SERVICE
Capacity Control is accomplished by a suction
pressure actuated unloader which controls two
cylinders. Unloaders are factory set, as shown in
Table 1, but may be field adjusted.
CONTROL SET POINT (cylinder load point) is
adjustable from 0 to 85 psig. To adjust, turn
control set point adjustment nut (Fig. 8) clockwise
to its bottom stop. In this position, set point is 85
psig. Then, turn adjustment counterclockwise to
desired control set point. Every full turn counter¬
clockwise decreases set point by 7.5 psig.
4
474

CONTROL
SET POINT
ADJUSTMENT
NUT
PRESSURE
DIFFERENTIAL
ADJUSTMENT
SCREW
VALVE BODY
DIFFERENTIAL SCREW
SEALING CAP
(CAP MUST BE REPLACED
TO PREVENT REFRIGERANT LEAKAGE)
Fig. 8 — Compressor Capacity Control Unloader
PRESSURE DIFFERENTIAL (difference between
cylinder load and unload points) is adjustable from
6 to 22 psig. To adjust, turn pressure differential
adjustment screw (Fig. 8) counterclockwise to its
back stop position. In this position, differential is 6
psig. Then, turn adjustment clockwise to desired
pressure differential. Every full turn clockwise
increases differential by 1.5 psig.
Compressor Lockout Circuit — Units 38AD012
and 014 have a control to provide positive com¬
pressor lockout protection if an overcurrent or
overtemperature device trips out. The over current
protection devices (thermally actuated, automatic
reset overloads) are located in compressor terminal
box. Also, an overtemperature thermostat is im¬
bedded in compressor motor windings on “across-
the-line start” units. The “part-winding-start” units
have a thermostat externally mounted on compres¬
sor body.
TO RESTART COMPRESSOR - After determin¬
ing cause of compressor lockout and performing
required corrective action, push reset button on
control box door.
The lockout circuit will automatically reset
after shutdown due to power failure.
Time Guard Circuit for each compressor provides
for a 5-minute delay before restarting compressor
after shutdown for any reason. On start-up, the
Time Guard Timer causes a delay of 15 seconds
after thermostat closes, and fans start before
compressor will start. On 38AD012 and 014;460-
and 575-volt units outdoor air fan no. 2 starts up
with compressor. On compressor shutdown the
timer recycles for 4 minutes 45 seconds. During
this time the compressor cannot restart.
Head Pressure Control — A feeler bulb in the
condenser inlet airstream senses temperature of air
entering condenser to control no. 2 fan on
38AD012 and 014 and no. 2 and 3 on 38AD016.
Qpen and close temperatures of switch are shown
in Table 1.
Be sure that feeler bulb is not in direct contact
with coil surface. See INSTALLATION, Fan
Cycling Thermostat.
MOTORMASTER® SOLID STATE HEAD PRES¬
SURE CONTROLLER (32 Series accessory) may
be used on these units. Controller modulates rpm
of no. 1 condenser fan motor from zero to full
speed to provide condensing pressure control and
operation at lower ambient temperatures.
On 460-volt units, install a field-supplied trans¬
former and rewire condenser fan motor no. 1 for
230 volts.
On 575-volt units, install a field-supplied trans¬
former and replace 575-volt motor with 230-volt
motor (Carrier part no. HC44VL851 or
HC44VE851).
Crankcase Heater prevents refrigerant migration
and compressor oil dilution during shutdown
whenever compressor is not operating.
Both compressor service valves must be closed
whenever crankcase heater is de-energized for more
than six hours.
Fan Adjustment - Turn unit power off. Remove
fan guard and loosen hub setscrew. Adjust fan until
top surface of hub is 3/8 in. below top of venturi
rim as shown in Fig. 7. Then, tighten setscrew on
flat of motor shaft. Replace rubber hubcap. If
rubber hubcap is missing, seal fan hub recess with
permagum to prevent hub from rusting to motor
shaft.
Lubrication
FAN MOTORS have sealed lubricated bearings. No
provisions for lubrication are made.
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.
Fig. 9 — Fan Adjustment
5

To Add or Remove Compressor Oil
1. Pump down compressor to 2 psig and close
suction and discharge service valves. Vent re¬
maining pressure in compressor to atmosphere.
2. Add oil thru oil filler connection.
3. To remove oil, remove compressor crankcase oil
drain plug.
Refer to Carrier Standard Service Techniques
Manual, Chapter 1, for complete instructions on
checking, adding or removing compressor oil.
Cleaning Coils — The coils can be cleaned with a
vacuum cleaner, washed out with water, blown out
with compressed air, or brushed. Fan motors are
drip proof but not waterproof.
TROUBLESHOOTING GUIDE
COMPRESSOR DOES NOT RUN
Contactor Open
Power off — restore power.
Fuses blown — replace with correct fuses.
Control circuit breaker open - check for short circuit in
control wiring.
Transformer dead — replace transformer if primary
windings are receiving power.
Thermostat circuit open — check thermostat setting.
Timer motor defective — replace timer.
Compressor lockout circuit open — check for excessive
compressor current draw (140% FLA max allowable) or
excessive motor temperature (motor thermostat opens).
After corrective action, press reset button.
Low-pressure switch open — check for refrigerant
undercharge or obstruction of indoor air flow.
High-pressure switch open — check for refrigerant
overcharge or obstruction of outdoor air flow.
Connections loose — tighten all connections.
Compressor stuck — see 06D service literature.
Contactor Closed
Compressor leads loose — check connections.
Motor windings open — see 06D compressor service
literature.
Single phasing - replace blown fuse.
Contactor Closed Then Open
If compressor lockout circuit is open — see Contactor
Open.
If compressor lockout circuit is closed — see Compressor
Cycles on High- (or Low-) Pressure Switch.
COMPRESSOR CYCLES ON HIGH-PRESSURE
SWITCH
Condenser Fan On
High-pressure switch faulty — replace switch.
Air flow restricted — remove obstruction.
Air recirculating — clear airflow area.
Noncondensables in system — purge and recharge as
required.
Refrigerant overcharge - purge as required.
Line voltage incorrect — consult power company.
Refrigerant system restrictions — check or replace
filter-drier, expansion valve, etc.
Condenser Fan Off
Fan slips on shaft — tighten fan hub setscrews.
Motor not running — check power and capacitor.
Motor bearings stuck — replace bearings.
Motor overload open — check overload rating. Check for
fan blade obstruction.
Motor burned out — replace motor.
COMPRESSOR CYCLES ON LOW-PRESSURE
SWITCH
Evaporator Air Fan Running
Filter-drier plugged — replace filter-drier.
Expansion valve power head defective — replace power
head.
Low refrigerant charge — add charge. Check low-
pressure switch setting.
Air Flow Restricted
Coil iced up — check refrigerant charge.
Coil dirty — clean coil fins.
Air filter dirty — clean or replace filters.
Dampers closed — check damper operation and position.
Evaporator Air Fan Stopped
Electrical connections loose — tighten all connections.
Fan relay defective — replace relay.
Motor overload open — power supply.
Motor defective — replace motor.
Fan belt broken or slipping — replace or tighten belt.
COMPRESSOR RUNS BUT COOLING
INSUFFICIENT
Suction Pressure Low
Refrigerant charge low — add refrigerant.
Low-pressure switch setting too high — adjust to correct
setting.
Head pressure low — check refrigerant charge. Check
condenser air fan thermostat settings.
Air filters dirty — clean or replace filters.
Expansion valve power head defective — replace power
head.
Evaporator coil partially iced — check low-pressure
setting.
Evaporator air flow restricted — remove obstruction.
Suction Pressure High
Compressor valves defective — see 06D service literature.
Heat load excessive — check for open doors or windows.
For replacement items use Carrier Specified Parts.
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Tab 4 Form 38AD-4SI Supersedes 38AD-3SI Printed in U.S.A 474 9-71 Codes B and MS Catalog No. 533—824