Carrier 50DPE014 Dimensions and installation guide

HEATING & COOLING
50DPE014
50DP016,020
Single-Package Cooling Units
Installation, Start-Up and Service Instructions
CONTENTS
Page
SAFETY CONSIDERATIONS. !
INSTALLATION .1-10
Step 1 — Provide Unit Support. 1
• ROOF CURB
• ALTERNATE UNIT SUPPORT
Step 2 — Rig and Place Unit. I
• POSITIONING
• ROOF MOUNT
Step 3 — Field Fabricate Ductwork.6
Step 4 — Make Unit Duct Connections.6
Step 5 — Trap Condensate Drain .6
Step 6 — Make Electrical Connections.7
• FIELD POWER SUPPLY
• FIELD CONTROL WIRING
Step 7 — Make Outdoor Air Inlet
Adjustments.7
• MANUAL OUTDOOR AIR DAMPER
• OPTIONAL ECONOMIZER
Step 8 — Install Outdoor Air Hood. 10
START-UP.10-13
SERVICE.14-16
SAFETY CONSIDERATIONS
Installation and servicing of air conditioning equip¬
ment can be hazardous due to system pressure and elec¬
trical components. Only trained and qualified service
personnel should install, repair or service air conditioning
equipment.
Untrained personnel can perform basic maintenance
functions of cleaning coils and filters and replacing
filters. All other operations should be performed by
trained service personnel. When working on air condi¬
tioning equipment, observe precautions in the literature,
tags and labels attached to the unit and other safety pre¬
cautions that may apply.
Follow all safety codes. Wear safety glasses and work
gloves. Use quenching cloth for unbrazing operations.
Have fire extinguishers available for all brazing
operations.
A WARNING ,
Before performing service or maintenance operations
on unit, turn off main power switch to unit. Electrical
shock could cause personal injury.
INSTALLATION
Step 1 — Provide Unit Support
ROOF CURB — Assemble and install accessory roof
curb in accordance with instructions shipped with this
accessory. Accessory roof curb and information required
to field fabricate a roof curb are shown in Fig. 1 and 2.
Install insulation, cant strips, roofing and flashing as
shown. Ductwork can be installed to roof curb before unit
is set in place. Curb should be level. Unit leveling toler¬
ance is ± 1/16 in. per linear ft in any direction. This is
necessary to permit unit drain to function properly. Refer
to Accessory Roof Curb Installation Instructions for
additional information as required.
ALTERNATE UNIT SUPPORT — When the curb
cannot be used, support unit with sleepers using unit curb
support area. If sleepers cannot be used, support long
sides of unit with a minimum of 3 equally spaced 4-in. x
4-in. pads on each side.
Step 2 — Rig and Place Unit — Inspect unit for
transportation damage. File any claim with transporta¬
tion agency. Do not drop unit, keep upright. Use spreader
bars over unit to prevent sling or cable damage. Rollers
may be used to move unit across a roof. Level by using
unit frame as a reference; leveling tolerance is ± 1/16 in.
per linear ft in any direction. See Fig, 3 for additional
information. Unit weight is shown in Table 1.
Four lifting holes are provided in ends of unit base rails
as shown in Fig. 3. Refer to rigging instructions on unit.
POSITIONING — Provide clearance around and above
unit for airflow, safety and service access (Fig. 4).
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Bookll |4 PC111 Catalog No 565-104 PrintedinUSA Form 50DP-26SI Pg 1 7-88 Replaces: 50DP-25SI
Tab |lb|6b

NOM lf*4"
(32) x (102)
TYP. 4 PLACES
ROOF OPENINGS
Dimensions
millimeters.
Attach all ductwork to roof curb
Field installation of sidewall insulation
is mandatory
INSULATION FIELD SUPPLIED
(SEE NOTE 3)
Fig. 1 — Roof Curb Details
INDOOR AIR INDOOR AIR
FAN MOTOR FAN MOTOR
50DPE0I4, 50DP0I6 50DP020
(50PQ900I5I) TRANSITION DUCT
Fig. 2 — Side Supply/Return Curb Details
Do not install unit in an indoor location. Do not locate
unit air inlets near exhaust vents or other sources of
contaminated air.
Although unit is weatherproof, guard against water
from higher level runoff and overhangs.
ROOF MOUNT — Check building codes for weight dis¬
tribution requirements. Unit weight is shown in Table 1.
RIGGING WEIGHTS* (lb)
MODEL
COIL FIN MATERIAL
OUTDOOR/INDOOR
AI/AI
Cu/AI Cu/Cu
50DPE014 1880 1960
2040
50DP016
1880 1960
2040
50DP020
2390
2520 2630
‘Includes economizer weight
NOTE Rig by inserting hooks into unit base rails as shown Main¬
tain a distance of 120 in (3048 mm) from top of unit to eyehook
Use corner post from packaging to protect coil of unit from
damage by rigging cable. Use bumper boards for spreader bars
CAUTION!
All panels must be in place when rigging.
Fig. 3 — Rigging Details
2

25% AIR OR ECONOMIZER HOOD
[D> INDOOR AIRFLOW
OUTDOOR AIRFLOW
f '> ALTERNATE AIRFLOW
Fig. 4 — Physical Data and Dimensions
^ SPACE REQUIRED FOR
SERVICE AND AIRFLOW
3

Table la — Physical Data — 50DPE014
UNIT SIZE
50DPE014
OPERATING WEIGHT (lb)
Unit (Outdoor Coil/Indoor Coil)
AI/AI
1470
Al/Cu
1550
Cu/Cu
1630
Roof Curb
200
Economizer
110
Electric Heat
65
Alternate Motor and Drive
5
COMPRESSOR
Semi-Hermetic — 6 Cylinders
Quantity
1
Oil (oz)
160
REFRIGERANT
Charge (lb) Sys 1*, Sys 2
20 8
REFRIGERANT METERING DEVICE Capillary Tubes
Upper Circuit
Quantity...Length...ID/OD (in.)
6 25 0 055/0 125
6 25 0 055/0 125
6.25.0 055/0 125
OUTDOOR COIL
Copper Tube, Aluminum or Copper Plate Fins
Rows
3
Fins/in.
Aluminum
136
Copper
124
Total Face Area (sq ft)
189
OUTDOOR AIR FAN
Propeller Type, Direct Drive
Nominal Cfm
12,000
Quantity...Diameter (in.) 2 ..26
Motor Hp (1075 Rpm)
1
INDOOR COIL
Copper Tube, Aluminum or Copper Plate Fins
Rows
3
Fins/in.
Aluminum
14.3
Copper
13 1
Total Face Area (sq ft)
165
INDOOR AIR FANf
Centrifugal, Belt Drive
Quantity...Size (in.)
2 .10x10
Nominal Cfm
5000
Rpm Range Std
805-1093
Opt 978-1265
Max Allowable Rpm
1550
Motor Pulley Pitch Diameter (in.) Std
2 8-3.8
Opt
3 4-4.4
Fan Pulley Pitch Diameter (in.)
6.0
Belt, Quantity...Type...Length (in.)
1. V. 43
Speed Change per Full Turn Std
58
of Moveable Pulley Flange (Rpm) Opt
57
Moveable Pulley Max Full Turns
from Closed Position
Factory Setting — Full Turns Open
3
Factory Speed Setting (Rpm) Std
920
Opt
1092
Motor Hp (Service Factor) Std
2 (1 15)
Opt
3 (1 15)
HIGH-PRESSURE SWITCH
Cutout (psig)
428
Reset (psig)
320
LOW-PRESSURE SWITCH (Liquid Line)
Cutout (psig)
27
Reset (psig)
60
AIR INLET SCREENS
Economizer, Number...Size (in.)
2 20x25x1
1 20x20x1
INDOOR AIR FILTERS (Type)
10% Efficient — Disposable Fiberglass
Number...Size (in.)
2. 20x20x2
3.16x20x2
2 16x25x2
‘System 1 consists of upper portion of outdoor coil and lower portion of indoor coil
tUnits have adjustable standard and alternate drives
4

Table 1b — Physical Data — 50DP016,020
UNIT SIZE
50DP016
50DP020
OPERATING WEIGHT (lb)
Unit (Outdoor Coil/Indoor Coil)
AI/AI
Al/Cu
Cu/Cu
Roof Curb
Economizer
Electric Heat
1470
1550
1630
2i
1
■
1980
2110
2220
00
10
65
COMPRESSOR
Quantity
Oil (oz)
Semi-Hermetic
1
160
: — 6 Cylinders
2
160 ea
REFRIGERANT
Charge (lb) Sys 1*, Sys 2
R-22
21.2
R-22
17.0, 17.0
REFRIGERANT METERING DEVICE
Upper Circuit
Quantity...Length...ID/OD (in.)
Lower Circuit
Quantity...Length...ID/OD (in.)
Capillai
6.40. 0.065/0 125
6..20.0 055/0.125
6.20 0 055/0 125
y Tubes
13.25.0 055/0 125
13 .25 ..0 055/0.125
OUTDOOR COIL
Rows
Fins/in.
Aluminum
Copper
Total Face Area (sq ft)
Copper Tubes, Alumini
3
136
12.4
18.9
jm or Copper Plate Fins
4
13.6
12.4
22.2
OUTDOOR AIR FAN
Nominal Cfm
Number...Diameter (in.)
Motor Hp (1075 Rpm)
Propeller Typ
12,000
2 .26
1
ie, Direct Drive
11,400
2. .26
1
INDOOR COIL
Rows
Fins/in.
Aluminum
Copper
Total Face Area (sq ft)
Copper Tubes, Alumini
3
143
13 1
16.5
um or Copper Plate Fins
4
14.4
13.1
17.9
INDOOR AIR FANf
Quantity...Size (in.)
Nominal Cfm
Rpm Range Std
Opt
Pulley A
Pulley B
Maximum Allowable Rpm
Motor Pulley Pitch Diameter (in.) Std
Opt
Pulley A
Pulley B
Fan Pulley Pitch Diameter (in.)
Belt, Quantity...Type...Length (in.)
Speed Change per Full Turn Std
of Moveable Pulley Flange (Rpm) Opt
Moveable Pulley Max Full Turns
from Closed Position
Factory Setting — Full Turns Open
Factory Speed Setting (Rpm) Std
Opt
Pulley A
Pulley B
Motor Hp (Service Factor) Std
Opt
Centrifuga
2 ..10x10
6000
916-1186
1158-1428
1550
3 4-4 4
4 3-5 3
6.4
1. .V...45
54
55
5
3.5
970
1240
3 {1 15)
il, Belt Drive
2 .12x12
7200
848
1060
1550
32
40
6.6
2 V..45
848
1060
5 (1 15)
HIGH-PRESSURE SWITCH
Cutout (psig)
Reset (psig)
428
320
LOW-PRESSURE SWITCH (Liquid Line)
Cutout (psig)
Reset (psig)
27
60
AIR INLET SCREENS
Economizer, Number...Size (in.)
2. .20x25x1
1...20x20x1
INDOOR AIR FILTERS (Type)
Number...Size (in.)
10% efficient — D
2 20x20x2
3. 16x20x2
2. .16x25x2
isposable Fiberglass
4 20x20x2
4.. 16x20x2
'System 1 consists of upper portion of outdoor coil and lower
portion of indoor coil, except for size 020 which is intertwined
|016 unit has adjustable standard and alternate drives The 020
unit does not have an alternate drive, but has 2 non-adjustable
pulleys Pulley A is installed in unit, pulley B is shipped with unit
5

Step 3 — Field Fabricate Ductwork — Secure all
ducts to building structure. Use flexible duct connectors
between unit and ducts as required. Insulate and weather¬
proof all external ductwork, joints and roof openings
with flashing and mastic in accordance with applicable
codes.
Ducts passing through an unconditioned space must
be insulated and covered with a vapor barrier.
A minimum clearance is not required on 50DPE014
and 50DP016 units. The 50DP020 units with electric
heat require one-in. clearance the first 24 in. of ductwork.
Outlet grilles must not lie directly below unit discharge.
Step 4 — Make Unit Duct Connections — Unit
is shipped for through-the-bottom duct connections.
Ductwork openings are shown in Fig. 1 and 4. Duct
connections are shown in Fig. 5. Field-fabricated con¬
centric ductwork may be connected as shown in Fig. 6 and
7. Attach all ductwork to roof curb and roof curb base-
pans. Refer to installation instructions shipped with
accessory roof curb.
50DR DPE0I2, 014 50DP0I6
INDOOR FAN MOTOR
NOTE Do not drill in this area, damage to basepan may result
in water leak.
Fig. 5 — Air Distribution — Through-the-Bottom
Step 5 — Trap Condensate Drain — See Fig. 4
and 8 for drain location. Plug is provided in drain hole
and must be removed when unit is operating. One 3/4-in.
half coupling is provided inside unit evaporator section
for condensate drain connection. An 8-1/2 in. x 3/4-in.
diameter and 2-in. x 3/4-in. diameter pipe nipple coupled
to standard 3/4-in. diameter elbows provide a straight
path down through holes in unit base rails (see Fig. 9).
A trap at least 4 in. deep must be used and must be pro¬
tected against freeze-up.
NOTE: Do not drill in this area, damage to basepan may result
in water leak
Fin 6 — Concentric Duct Air Distribution
Shaded area indicates block-off panels
NOTE. Dimension A, A1 and B, B1 are obtained from field-
supplied ceiling diffuser
Fig. 7 — Concentric Duct Details
Fig. 8 — Condensate Drain Details
6

(|")FPT
DRAIN CONNECTION-l-.
(HALF COUPLING) ^ r
BASE RAIL-
LI
TO TRAP <J>
Fig. 9 — Condensate Drain Piping Details
Step 6 — Make Electrical Connections
FIELD POWER SUPPLY — Unit is factory wired for
voltage shown on nameplate. Units are provided with
terminal block.
When installing units, provide a disconnect per NEC
of adequate size (Table 2).
All field wiring must comply with National Electrical
Code and local requirements.
Route power lines through control box end panel — or
unit basepan — (Fig. 4) to terminal connections as shown
on unit wiring diagram and Fig. 10.
i l
TBl
S I
— [ \d)\
EQUIP GND
Fig, 10 — Field Power Wiring Connections
Operating voltage to compressor must be within
voltage range indicated on unit nameplate. On 3-phase
units, voltages between phases must be balanced within
2% and the current must be balanced within 10%.
Use the following formula to determine the % voltage
imbalance.
% Voltage Imbalance
100 x max v °ltag e deviation from average voltage
average voltage
Example: Supply voltage is 460-3-60.
AB = 452 volts
BC = 464 volts
AC = 455 volts
Average Voltage =
452 + 464 + 455
1371
= 457
Determine maximum deviation from average voltage:
(AB) 457 452 = 5 volts
(BC) 464 - 457 = 7 volts
(AC) 457 - 455 = 2 volts
Maximum deviation is 7 volts.
Determine % voltage imbalance:
7
% Voltage Imbalance = 100 xyjyy = 1.53%
This amount of phase imbalance is satisfactory as it is
below the maximum allowable 2%.
IMPORTANT: If the supply voltage phase im¬
balance is more than 2%, contact your local electric
utility company immediately.
Unit failure as a result of operation on improper line
voltage or excessive phase imbalance constitutes abuse
and may cause damage to electrical components. Such
operation would invalidate any applicable Carrier
warranty.
FIELD CONTROL WIRING — Install a Carrier-
approved accessory thermostat assembly according to
installation instructions included with accessory. Locate
thermostat assembly on a solid wall in the conditioned
space to sense average temperature.
Route thermostat cable or equivalent single leads of
no. 18 AWG colored wire from subbase terminals
through conduit in unit to low-voltage connections as
shown on unit label wiring diagram and in Fig. 11.
NOTE: For wire runs up to 50 ft, use no. 18 AWG insu¬
lated wire (35 C minimum). For 50 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).
Set heat anticipator settings as indicated in Table 3.
Settings may be changed slightly to provide a greater
degree of comfort for a particular installation.
Refer to accessory remote control panel instructions
as required.
THERMOSTAT ASSEMBLY
REMOVABLE JUMPER r~°—\
gfipHS |wj] ^ [Yi] @ [G] [$ L [ X ]
is - ffl - is - s irsntr _ Enfns — iirDi
LOW-VOLTAGE TERMINAL BLOCK IN UNIT CONTROL BOX
Fig. 11 — Field Control Thermostat Wiring
Step 7 — Make Outdoor Air Inlet Adjustments
MANUAL OUTDOOR AIR DAMPER All units
(except those equipped with a factory-installed econo¬
mizer) have a manual outdoor air damper to provide
ventilation air. Damper can be preset to admit up to 25%
outdoor air into return air compartment. To adjust,
loosen securing screws and move damper to desired
setting then retighten screws to secure damper (Fig. 12).
OPTIONAL ECONOMIZER
Enthalpy Control Setting (location is shown in Fig. 13) —
For maximum benefit of outside air, set enthalpy control
to the A setting (Fig. 14).
7

25% ADJUSTABLE
AIR DAMPER
SECURING SCREWS
BASE
UNIT
Fig. 12 — 25% Outdoor Air Section Details
COOLING
LOCKOUT
SWITCH
ENTHALPY
CONTROL
DAMPER MOTOR
FILTERS
ECONOMIZER
CONTROL BOX
ECONOMIZER
DAMPER
ASSEMBLY
Fig. 14 — Enthalpy Control Assembly
Mixed Air Thermostat Setting — Set mixed air thermo¬
stat in return air compartment to desired temperature of
air delivered to the conditioned space (not less than 35 F
or condensation in unit will result).
Damper Vent Position Setting
1. Set fan switch at ON (continuous fan operation) and
close night switch if used.
2. Set system selector switch to OFF.
3. Remove cap from vent adjustment screw on damper
motor terminal box cover.
4. Turn adjustment screw slowly until dampers assume
desired vent position. Do not manually operate
damper motor; damage to motor will result.
Fig. 13 — Enthalpy Control Location
(Economizer Damper Assembly — End View)
8

Table 2 — Electrical Data
UNIT
MODEL
VOLTS-PH-HZ
VOLTAGE
RANGE
COMPR
OUTDOOR
FAN
MOTOR
r— -
INDOOR
FAN
MOTOR
—
FACTORY-
INSTALLED
HEATERS
POWER
SUPPLY
Min Max
RLA LRA Qty
FLA Hp
FLA
FLA
kW
Min Ckt 1 MOCP
Amps (Amps)
50DPE014
208/230-3-60 187
253 49 3 191 2
20
30
20
20
20
20
30
30
3 0
30
7 5
106
7 5
75
7 5
7 5
10 6
106
10 6
10 6
_
_
74/ 82
122
122/135
41/ 45
74/ 82
122
122/135
41/ 45
26/31
42*
42/52
14/17
26/31
42*
42/52
14/17
glut
460-3-60
414
508 22 1
86 2 33
2 0
30
2 0
20
20
3 0
30
30
3 4
48
34
34
34
48
48
48
21
39
66
21
39
66
16
30
51
16
30
51
II
575-3-60 518 632
17 9
69 2 26
20
30
2 0
3.0
2 7
3 9
2 7
3.9
37
37
37
37
31 45
32 45
50 50
52 60
50DP016
208/230-3-60
187
253
61
266
2 7 7 30
10 5
74/ 82
122/135
163
163/180
26/31
42/52
56*
56/69
16 217 82 225
2 i7/239 -mmm.
460-3-60
414
508
32 0 120 2
33 30
48
_
39
66
96
30
51
73
H
575-3-60 518 632
25 6
96
2
26 30 39
50 49
38 60
68 70
50DP020
208/230-3-60 187 254
49 3
(ea)
153
(ea)
2 77 5 0 16 7
74/ 82
122/135
163/180
26/31
42/52
56/69
iiH
460-3-60
414
508 199
(ea)
77
(ea)
2 33 5 0 7 6
39
66
96
30
51
73
i B
Fuse only, unshaded values indicate fuses or circuit
breakers may be used
Compr
FLA
Hp
Compressor
Full Load Amps
Horsepower
LRA — Locked Rotor Amps
MOCP — Maximum Overcurrent Protection
RLA — Rated Load Amps
*CSA-approved heaters are rated at 208 volts only
Q

Step 8 — Install Outdoor Air Hood — The out¬
door air hood is common to 25% air ventilation and
economizer. If economizer is used, all electrical connec¬
tions have been made and adjusted at the factory.
Assemble and install hood in the field.
NOTE: The hood top cover, upper and lower filter
retainers, hood drain pan and filter support bracket are
secured to the top crate above the condenser fans. The
screens, hood side panels, remaining section of filter
support bracket and all other hardware are in a package
located inside the return-air filter access panel (Fig. 15
and 16).
OUTDOOR AIR HOOD AND
MOUNTING BRACKETS
Fig. 15 — Outdoor Air Hood
Component Location
UNIT TOP CRATE
Fig. 16 — Outdoor Air Hood Components
START-UP
Unit Preparation — Check that unit has been installed
in accordance with installation instructions and appli¬
cable codes.
Compressor Mounting — Loosen compressor hold¬
down bolts until sidewise movement of the washer under
each holddown bolt head can be obtained. Do not
loosen completely as bolts are self-locking and will main¬
tain adjustment.
Internal Wiring — Check all electrical connections
in unit control boxes; tighten as required.
Refrigerant Service Valves — The units have one
service valve on suction line, one on discharge line
and one on liquid line. Be sure valves are open.
Crankcase Heater(s) are energized as long as there is
power to the unit.
NOTE: Unit power must be on for 24 hours prior to
start-up.
1. Assemble hood top cover, side panels, upper filter
retainer and drain pan (Fig. 17).
2. Secure lower filter retainer and support bracket to
unit as shown in Fig. 17.
3. Loosen sheet metal screws for base unit top cover
located above outdoor air inlet opening.
4. Match notches in hood top cover to unit top cover
screws. Insert hood flange between unit top cover
flange and unit. Tighten screws.
5. Insert outdoor air inlet screens and spacer in channel
created by lower filter retainer and filter support
bracket.
6. Attach remaining section of filter support bracket.
Table 3 — Heat Anticipator Settings
UNIT MODEL
VOLTAGES
kW
STAGE 1 STAGE 2
14-17
40
—
208-230/3/60 26-31
40 40
50DPE014
42-52 66
40
1 16
40
—
460/3/60
30 .40
40
51
40 66
26-31
40 66
208-230/3/60
42-52 66 .40
50DP016,020
56-69
66 66
30
40
40
460/3/60
51 40 66
73 .66 66
10

Table 4 — Air Quantity Limits
UNIT MODEL
MIN CFM
MAX CFM
50DPE014 3750
6250
50DP016
4500
7500*
50DP020 5400
9000
Mndoor Fan Max Watts = 3000
Indoor Air Fan — Fan belts and pulleys are factory
installed. Belts are secured to pulleys with tape.
Remove tape and, if required, adjust as described in
Service, Indoor Air Fan Adjustment.
50DP020 has 2 non-adjustable pulleys. Pulley A is
installed in unit. Pulley B is shipped in cardboard box
taped to vestibule below main control box.
Outdoor Air Fans and Motors are factory set. Refer
to Service, Outdoor Air Fan Adjustment as required.
Return Air Filters — Check that correct filters are
installed in filter tracks. See Table 1. Do not operate unit
without return air filters.
Outdoor Air Inlet Screens — Outdoor air inlet
screens must be in place before operating unit.
Economizer Section — Remove filter access
panel. Check that outdoor air damper is closed and return
air damper is open.
Economizer operation and adjustment is described in
Start-Up, Economizer Operation; and Service, Econo¬
mizer Adjustment, respectively.
Base Unit Operation
COOLING — Unit power on. System selector switch at
COOL; fan switch at AUTO.; thermostat at a setting
below room temperature.
50DPEQ14 and 50DP016 — Compressor starts unloaded
on closure of No. 1 contact in thermostat.
Additional rise in room temperature closes contact
No. 2 in thermostat which de-energizes the unloader coil.
Compressor is now fully loaded.
Check cooling effects at a setting below room tempera¬
ture. Check unit charge. Refer to Service, Refrigerant
Charge.
Reset thermostat at a temperature above room tem¬
perature. Compressor(s) will shut off.
50DP020 — Upon a rise in room temperature, cooling
contact No. 1 in the thermostat closes, energizing the
first-stage cooling contactor and the indoor fan con¬
tactor. The first-stage compressor, outdoor fan motor
and indoor fan motor start and run.
Upon a further rise in room temperature, cooling
contact No. 2 in the thermostat closes, energizing the
second-stage cooling contactor. The second-stage
compressor starts and runs.
To Shut Off Unit — Set system selector switch at OFF
position or reset thermostat above room temperature.
Units with Signal-LOC ™ protection device shut down on
any safety trip and thermostat light comes on. Determine
reason for safety trip. Restart compressor(s) by resetting
circuit breaker at unit.
HEATING — Turn on main power to unit. Set system
selector switch at HEAT, fan switch at AUTO.; and
thermostat at a setting above room temperature. First
stage of electric heater elements are energized on closing
of heating contact No. I in thermostat. On a further fall
of room temperature, heater contact No. 2 closes ener¬
gizing second-stage electric heater elements.
To Shut Off Unit — Set system selector switch at OFF.
VENTILATION AIR CIRCULATION (Continuous
Fan) — Unit power on. System selector switch at OFF,
HEAT or COOL; fan switch set at ON. Indoor fan con¬
tactor is energized through the switch on the thermostat,
and the indoor fan runs continuously.
AUTOMATIC CHANGEOVER (with Automatic
Changeover Thermostat) — System selector switch set
at AUTO. When temperature of conditioned space rises
to cooling selector lever setting, unit automatically
switches from heating mode to cooling mode. When tem¬
perature of the conditioned space falls to the heating
selector lever setting, unit automatically changes from
cooling mode to heating mode. The thermostat is inter¬
locked so that cooling and heating systems do not operate
at the same time.
HEAD PRESSURE CONTROL All units have fan
cycling thermostats which, at 55 F, shut off one outdoor
fan motor. This permits unit to operate down to 40 F
outdoor air temperature.
Economizer Operation — If unit is equipped with
modulating outdoor air control (economizer), it should
operate as follows:
COOLING MODE — Indoor and outdoor fans and com¬
pressor energize when there is a call for cooling and
enthalpy of outdoor air is above enthalpy control setting.
The economizer damper moves to VENT position.
Indoor fan starts and economizer damper opens fully
on a first-stage call for cooling when enthalpy of outdoor
air is below the enthalpy control setting. Compressor
remains off.
Compressor is energized and mechanical cooling
integrates with economizer cooling upon a second-
stage call for cooling. If outdoor air temperature falls
below 50 F, cooling lockout switch prevents compressor
from operating.
Economizer damper modulates when mixed air tem¬
perature is below mixed air thermostat setting.
A freeze protection thermostat (FPT) is located on the
indoor coil. It detects ice buildup and turns off the
compressor, thus allowing the coil to clear. Once ice
melts, the compressor can be re-energized.
HEATING MODE' — Outdoor air damper stays at
VENT position while indoor air fan runs.
NOTE: If fan switch is at ON position, and room thermo¬
stat is satisfied, damper goes to ventilation position.
11

Variable Volume Units — Units suitable for use with
variable volume air handling systems are equipped with 2
electric unloaders on the compressor. The control panel
for these units (Fig. 18) consists of a step controller, a
proportional thermostat, a 7-day timer and a power
switch.
Before starting unit, open compressor service valves
and liquid line shutoff valve. Be sure compressor crank¬
case heaters have been on for 24 hours and that crankcase
oil level indicates half full.
CONTROL SEQUENCE CHECKOUT
1. Turn on unit main power supply. Be sure unit is ready
to operate.
2. Set variable volume control panel POWER switch
at ON.
3. If supply air leaving unit is above 50 F (or other field-
set temperature), step controller will operate to de¬
energize compressor unloader solenoids (compressor
loads up) until set temperature is achieved. An interval
of 13.5 minutes is required to maximum loading
position. Refer to unit label diagram for unloader
sequencing. Also see Fig. 19.
4. Step controller, 7-day timer and proportional thermo¬
stat are factory set and adjusted. If other settings
or changes in adjustment are required, refer to dis¬
cussion of these items.
SEVEN-DAY TIMER ADJUSTMENT — Factory
settings are ON — 6:30 A.M.; OFF — 7:30 P.M. for each
of 7 days.
1. On the timer dial face (Fig. 18), loosen the thumb¬
screws which position the system ON and OFF
trippers.
2. Set trippers at desired system ON and OFF time
settings and tighten thumbscrews. Skipping a day(s) is
accomplished by removing trippers from the dial.
3. Set the timer by turning the dial face clockwise until
fixed pointer indicates correct day and time. Do not
turn dial face counterclockwise. Do not move fixed
pointer.
PROPORTIONAL THERMOSTAT — The propor¬
tional thermostat, Fig. 18, monitors temperature of the
conditioned air leaving unit. On signal from the thermo¬
stat, sequence motor operates cam switches to load or
unload compressor to maintain thermostat setting.
Thermostat is factory set at 50 F ± 6 F but may be reset
between 0°F and 100F as follows:
Temperature Setting — Turn knob on front of case until
pointer indicates desired set point temperature. This is
the center point of proportional range.
Range Adjustment — Remove cover and turn adjustment
wheel until pointer indicates desired range.
If sequencer motor shaft constantly moves back and
forth, increase proportional thermostat range (about 5 F
at a time) until system is stable.
TERMINAL POWER PROPORTIONAL
BLOCK NO I SWITCH THERMOSTAT
Fig. 18 — Control Panel, Variable Volume Limits
12

STEP CONTROLLER — The step controller consists of
a reversible electric motor which drives a set of cams that
activate up to 5 snap-acting switches. Each cam is adjust¬
able to operate at any point on the 160 angular degrees of
camshaft rotation. The differential of each system may be
adjusted from a minimum of 5 angular degrees to a maxi¬
mum limited only by the 160 angular degrees of camshaft
rotation.
Rotational direction is controlled by the proportional
thermostat through the step controller feedback poten¬
tiometer and balancing relay.
Determining Switch Settings — Switches are factory set
at angular settings as shown in Fig. 19 (also shown on unit
label diagram). To reset, if desired, determine angular
differential for each switch and between switches. Then
determine minimum differential or throttling range of
proportional thermostat to provide desired step con¬
troller differential or throttling range. This range should
be wide enough to prevent rapid cycling from one
capacity step to another. Then adjust cams to new settings
as required.
MAKE BREAK
POINT POINT
Fig. 20 — Step Controller Cam Adjusting
Details (Motor End View)
Cam Adjustments — The step controller is shipped with
cams set to operate switches (i.e. compressor unloaders)
as shown in Fig. 19. All switches are closed (compressor
unloaded). The shaft is positioned all the way counter¬
clockwise (as viewed from motor end).
Using the following procedure, first adjust all operating
points in one direction of motor drive. Then reverse
motor direction and adjust switch differentials. Use
potentiometer wiper as an approximate indicator of
angular adjustments using angular displacement scale
mounted on potentiometer back plate. Also see Fig. 20.
12 3 4
STEP CONTROL SWITCH
Fig. 19 — Step Controller Sequence
1. Loosen all bushing setscrews with a 1/16-in. Allen
wrench. Loosen all cam hex screws with a 3/16-in.
open-end wrench.
If setscrews are not accessible from top of controller,
operate motor to rotate cams and bushings by shorting
terminals R and B for counterclockwise rotation and
terminals R and W for clockwise rotation.
2. Momentarily de-energize motor to permit motor to
recycle to start position. Jumper terminals R and W to
run motor camshaft to desired position for operating
first switch. Stop motor in this position by removing
jumper between terminals S and T.
3. Starting with first switch, turn cam clockwise until
switch makes an audible “click” as roller moves up cam
rise to higher level. This is the operating point. Lock
bushing setscrews.
4. Set operating point of each of remaining switches in
like manner. Advance motor by momentarily jumper¬
ing terminals S and T.
5. Set switch differential by reversing motor (short
terminals R and B) and running it to desired break
point. Stop motor at this point by de-energizing power
at LI (POWER switch off). Start at last switch and
progress to first switch.
Move differential cam clockwise so that roller is on
high part of cam. Be sure that switch is at make
position. To check this, manually lift roller assembly
to make switch. Move differential cam counterclock¬
wise until roller drops to low level of cam. At this
point, switch should break. Lock the hex screw.
6. Check settings by performing Control Sequence
Checkout.
7. If 115-volt to step controller is de-energized, timer
recycles to start point when power is restored.
13

SERVICE
A WARNING
Before performing service or maintenance operations
on unit, turn off main power switch to unit. Turn off
accessory heater power switch if applicable. Elec¬
trical shock could cause personal injury.
Cleaning — Inspect unit interior at beginning of each
heating and cooling season or as operating conditions
require. Remove unit top panel and/or side panels for
access to unit interior.
INDOOR COIL — Clean with a commercial coil cleaner.
OUTDOOR COIL — Clean outdoor coil annually or as
required by location or outdoor air conditions. Inspect
coil monthly — clean as required.
CONDENSATE DRAINS —Check and clean each year
at start of cooling season. In winter, keep drains and traps
dry or protect against freeze-up.
FILTERS — Clean or replace at start of each heating
and cooling season, or more often if operating conditions
require. Refer to Table 1 for type and size.
OUTDOOR AIR INLET SCREENS — Clean screens
with steam or hot water and a mild detergent. Do not use
throwaway filters in place of screens.
Lubrication
COMPRESSORS — Each compressor is charged with
correct amount of oil at the factory.
FAN SHAFT BEARINGS — No lubrication required.
Bearings are permanently lubricated.
FAN MOTOR BEARINGS — No lubrication of out¬
door fan or indoor blower motors are required for first
5 years of operation. Annually thereafter, clean and
repack bearings with a suitable bearing grease.
5. Set movable flange at nearest keyway of pulley hub
and tighten setscrew. (See Table 1 for speed change for
each full turn of pulley flange.)
To align fan and motor pulleys, loosen fan pulley set¬
screws and slide fan pulley along fan shaft. Make angular
alignment by loosening motor from mounting plate.
Fig. 21 — Indoor Air Fan Pulley Adjustment
(50DPE014 and 50DP016)
To Adjust Belt Tension — Loosen fan motor pivot
bolts. Move motor mounting plate up or down for proper
belt tension (1/2-in. deflection with one finger) and
tighten pivot bolts. Adjust lock bolt and nut on mounting
plate to secure in fixed position.
Outdoor Air Fan Adjustment (Fig. 22) — Shut off
unit power supply. Remove fan top grille assembly and
loosen fan hub screws. Adjust fan height on unit using a
straight edge placed across the fan orifice, tighten
setscrews and replace rubber hubcap to prevent hub from
rusting to motorshaft. Fill hub recess with permagum if
rubber hubcap is missing.
Indoor Air Fan Adjustment — Fan motor pulleys
are factory set for speed shown in Table 1. The 50DP020
units have fixed pulleys. Fan speed can be adjusted
only by changing the pulley. To change fan speed on
50DPE014 and 50DP016:
1. Shut off unit power supply.
2. Loosen belt by loosening fan motor mounting
plate nuts.
3. Loosen movable pulley flange setscrew (see Fig. 21).
4. Screw movable flange toward fixed flange to increase
speed and away from fixed flange to decrease speed.
Increasing fan speed increases load on motor. Do not
exceed maximum speed specified in Table 1.
See Table 4 for air quantity limits.
Fig. 22 — Outdoor Air Fan Adjustment
14

Economizer Adjustment
1. Set enthalpy control at its highest setting. If outdoor
temperature is above 70 F, perform the following:
install jumper between enthalpy control terminals 1
and 2 (red and yellow wires).
2. Set system selector switch at COOL and set cooling
selector lever at lowest setting. (Cooling mode may be
simulated by removing thermostat wires from termi¬
nals Y1 and Y2 [if used] and installing jumper between
Y1 and R.)
3. Set mixed air thermostat (MAT.) at lowest setting.
Outdoor air damper goes to fully open position
(indoor air damper closes).
4. Set mixed air thermostat at highest setting. Outdoor
air damper goes to fully closed position (indoor air
damper opens).
5. Adjust mechanical linkage for correct positioning
if necessary. If cooling was simulated in 2, remove
jumper and reconnect thermostat wire(s).
Power Failure — Dampers do not have a spring
return. In event of power failure, dampers remain in
position until power is restored. Do not manually
operate damper motor.
50DP020 Indoor Air Fan Motor Removal
NOTE: To remove belts only, follow steps 1 - 4.
1. Remove filter and supply air section access panels.
Remove center post (Fig. 4).
2. Loosen adjusting nuts A and E, Fig. 23.
3. Push motor away from indoor coil to zero adjustment.
Tighten nut A.
4. Remove belts from pulleys.
5. Remove holddown screws at B and C. Loosen screw
at D.
6. Holding motor and pulley securely, slide motor
mount assembly out of unit along slide tracks.
NOTE: To reinstall motor, reverse above procedure.
Fig. 23 — 50DP020 Indoor Fan Motor Section
Refrigerant Charge — Amount of refrigerant charge
is listed on unit nameplate and in Table 1. Refer to Carrier
Standard Service Techniques Manual, Chapter 1,
Refrigerants.
Unit panels must be in place when unit is operating
during charging procedure.
NO CHARGE — Use standard evacuating techniques.
After evacuating system, weigh in the specified amount of
refrigerant. (Refer to Table 1.)
LOW CHARGE COOLING — Using appropriate cool¬
ing charging chart, Fig. 24 or 25, add refrigerant until
conditions of the chart are met. Note that charging charts
are different from ones normally used. Charts are based
on charging units to correct superheat for various
operating conditions. An accurate pressure gage and
temperature sensing device are required. Connect tem¬
perature sensing device to service port on suction line and
insulate it so that outdoor ambient temperature does not
affect reading. Indoor air cfm must be within normal
operating range of unit.
TO USE COOLING CHARGING CHART — Take
outdoor ambient temperature and read the suction
pressure gage. Refer to chart to determine correct
suction temperature. If suction temperature is high, add
refrigerant. If suction temperature is low, carefully blow
some of the charge. Recheck suction pressure as charge
is adjusted.
Example: Fig. 24 — 50DPE014
Outdoor Temperature.85 F
Suction Pressure. 75 psig
Suction Temperature should be.60 F
(Suction Temperature may vary ± 5 F.)
If Chargemaster® charging device is used, temperature
and pressure readings must be accomplished using
appropriate charging chart.
Fig. 24 — Cooling Charging Chart —
50DPE014, 50DP016
15

SUCTION LINE TEMPERATURE (F)
Fig. 25 — Cooling Charging Chart — 50DP020
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
PC111 Catalog No 565-104 PrintedinUSA Form50DP-26SI Pg16 1090 7-88 Replaces: 50DP-25SI
Book 1 4
Tab
1b 6b