Carrier 50DP User Manual

Carrier Parkway • Syracuse NY 13221

Single-Package Cooling Units

INSTALLATION

Rigging and Unit Placement — Inspect unit for

transportation damage. File any claim with trans
portation agency. Do not drop unit. Keep unit
upright. Use spreader bars over unit to prevent

sling or cable damage. Rollers may be used to move

unit across a roof. Level unit by using unit frame as

a reference; unit leveling tolerance is ±1/16 in. per
linear ft in any direction. See Fig. 1 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. 1. Refer to rigging
instructions on unit. Refer to Accessory Roof Curb

Installation Instructions for additional information
as required.

Roof Curb — Assemble and install accessory roof

curb in accordance with instructions shipped with

this accessory. Refer to Fig. 2. Accessory roof curb

and information required to field fabricate a roof
curb of 2 in. X 12 in. planks is shown in Fig. 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 tolerance is ±1/16 in. per linear ft in

any direction. This is necessary to permit unit
drain to function properly.

Parrlor Pnrnnratinn 1Q7Q

Fig. 1 — Rigging Details

Form 50DP-9SI

Table 1 — Physical Data

UNIT SIZE 50DP
OPERATING WT (lb)

Unit

With Economizer

Roof Curb

COMPRESSOR

No. ... Type 2 ... P64

Oil (oz)

REFRIGERANT (Capillary Control) R-22

Charge (lb) Sys 1*, Sys 2

OUTDOOR COIL

Rows 2
F ins/in.
Total Face Area (sq ft)

OUTDOOR AIR FAN

Nominal Cfm

No. ... Diam (in.)

Motor Hp (1075 Rpm) 1/2

INDOOR COIL

Rows
F ins/in.
Total Face Area (sq ft)

INDOOR BLOWER

Qty ... Size (in.)
Nominal Cfm

Rpm Range
Max Allowable Rpm
Motor Pulley Pitch Diam (in.)

Fan Pulley Pitch Diam (in.)

Belt, No. ... 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)

Motor Hp (Service Factor)

HIGH PRESSURE SWITCH

Cutout (psig)
Reset (psig) 320

LOW PRESSURE SWITCH (Liquid Line)

Cutout (psig)
Reset (psig)

AIR INLET SCREENS

Economizer, No. ... Size (in.)

INDOOR AIR FILTERS (Type)

No. ... Size (in.)

Std 753-1066

Std 2 4-3.4

Std

Std 1 (1.25)

012

1350
1500

200

Hermetic -

76 ea

7 9, 6.6

14

18.9

9000

2 ..22

2

14

14.7

2 .. 10x10

4000

878-1191

1550

2.8-3.8

5.5

5.5

1 ... V .. 41

62
63

5
753
878

1-1/2 (1.20)

2 ... 16x20x2

4 .. 16x25x2 4 ... 16x23x2

- 2 Cy t inders

10% efficient — 2-in. D isposable Fiber Glass

014

1410
1560

200

2 ... P77

76 ea

R-22

8 3, 8.3

Copper Tube, Aluminum Plate Fins/in.

3

14

18 9

Prope 1 ler Type.

8000

2 22

1/2

Copper Tube, Aluminum Plate Fins/in

3

15

13.8

........................ _ .... .

Centrifugal, Adjustable Belt Drive

.............................................

2 10x10

5000
805-1093
978-1265

1550

2 8-3.8

3.4-4 4

6.0

6.0

1 ... V . 43

58
57

5
805
978

2 (1.15)
3 (1.15)

2 ... 20x25x1

1 .. 20x20x1

2 16x20x2

Direct Drive

428

27
60

016

1590
1740

200

Semi-Hermetic — 6 Cylinders

1 . 06DA537

160

R-22

23.2, -

3

14

18 9

12,000
2 ... 26

1

3

14

16.5

2 .. 10 X 10

6000

916-1 186

1158-1428

1550

3.4-4.4

4.3-5.3

6.4

6.4

1 . V ... 45

54
55

5

916

1158
3 (1 15)
3 (1 15)

4 ... 20x20x2

4 .. 16x20x2

t

•System 1 consists of upper portion of outdoor coil and lower portion of indoor coil

Roof Mount — Check building codes for weight

distribution requirements. Unit weight is shown in
Table 1.

Alternate Unit Support Methods — Where 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.

Positioning — Provide clearance around and above

unit for airflow, safety and service access. (Fig. 3)

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.

Outdoor Air Intake — The unit can be equipped

with an outdoor air damper (economizer) which

mixes outdoor air with return air.

Field-Fabricated Ductwork — Secure all ducts to

building structure. Use flexible duct connectors
between unit and ducts as required. Insulate and
weatherproof all external ductwork, joints and
roof openings with flashing and mastic in accord
ance with applicable codes.

Ducts passing thru • an unconditioned space

must be insulated and covered with a vapor barrier.

A minimum clearance is not required for any

air duct installation.

Outlet grilles must not lie directly below unit

discharge.

Unit Duct Connections — Unit is shipped for

thru'the-bottom duct connections. Ductwork

openings are shown in Fig. 2 and 3. Duct connec
tions are shown in Fig. 4. Field-fabricated con
centric ductwork may be connected as shown in

Fig. 5. Attach all ductwork to roof curb and roof

curb basepans.

Concentric duct details are shown in Fig. 6.
Also, refer to installation instructions shipped with
accessory roof curb.

Economizer Section — Remove filter access panel.

Check that outdoor air damper is closed and return
air damper is open.

Economizer operation and adjustment is de
scribed in Start-Up, Economizer Operation; and

Service, Economizer Adjustment, respectively.

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Fig. 2 — Roof Curb Details — 50DP012,014,016

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ÎS«PΫSUÎ.AriON

FiElP StJPPCiED

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7 2S?5i>Af«/aX)N0M}2Ef?ti00a. .

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[^IMOOOR Ai'?FLOW

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Fig. 3 — Physical Data and Dimensions

>Aa£RNAT£ AiRfLOW

------

! SPACE RECUIREC FOR

.....J SERVSCE AND AtRFUOW

Outside Air Damper (25% ventilation dir) -- Outside

air damper can be adjusted to permit up to 25%
outdoor air entry into return air compartment.

Outdoor Air Hood Installation (Fig. 3) — The

outdoor air hood is common to 25% air ventilation
and economizer. The economizer and all electrical
connections are factory installed and adjusted. The
hood assembly, outdoor air inlet screen(s) and
required hardware are shipped in a carton located
on outdoor fan section and must be field installed.

Using screws in carton install hood as follows;

1. Assemble hood top cover, side panels and
bottom track angle (Fig. 7).

Loosen base unit top cover sheet metal screws

2.

located above outdoor air inlet opening.

3.

Match notches in hood top cover to unit top

cover screws. Insert hood flange between unit

top cover flange and unit. Tighten screws.

4

Secure hood sides and bottom track angle to
unit. The screw on unit that matches bottom
track angle center hole must be removed prior
to assembly. Re-use screw to secure bottom
track angle to unit.

Insert outdoor air filters and spacer in hood

5.
filter tracks. NOTE: Hood may also be installed
by individually attaching hood parts to base
unit following sequence above.

6. Attach filter retainers to bottom track angle.

Indoor Blower — Blower belts and pulleys are

factory installed. Belts are secured to pulleys with
tape. Remove tape and, if required, adjust as
described in Service, Indoor Blower Adjustment.

Condenser Air Fans and Motors are factory set.

Refer to Service, Condenser Air Fan Adjustment as
required.

NOTE: Do not drill in this area, damage to basepan may result in
water leak

Fig. 5 — Concentric Duct Air Distribution

NOTE: Do not drill in this area, damage to basepan may result in
water leak

Fig. 4 — Air Distribution — Thru-the-Bottom

NOTE: Dimension A, A1 and B, B1 are obtained from field-supplied

ceiling diffuser

Fig. 6 — Concentric Duct Details

Condensate Drain — See Fig. 3 and 8 for drain

locations. Plugs are provided in both drain holes
and at least one must be removed when unit is
operating. Two 3/4-in. half couplings are provided
inside the unit evaporator section for the con
densate drain connection(s). 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 pro
vide a straight path down thru holes in the unit
base rails (see Fig. 9). A trap at least 4 in. deep
must be used and must be protected against
freeze-up. If only one drain connection is trapped,
other connection must be plugged.

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, 3, 4.)

All field wiring must comply with National

Electrical Code and local requirements.

Route power lines thru control box end panel
— or unit basepan — (Fig. 3) to terminal
connections as shown on unit wiring diagram and
Fig. 10.

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

drain i| drain hole

CONNECTION (BOTH SIDES)

Fig. 8 — Condensate Drain Details

3'ppT

* rSAÌWCOKfiECTlOÌ'ÌU_____

(HAt.fCOyPt.iSSi p i

SASEftfiit.

r

TO TRAP •5'

r

I

Fig. 9 — Condensate Drain Piping Details

f

VOLTS/PH/HZ

200/3/60

230/3/60

460/3/60 414 508

575/3/60 518 632

VOLTAGE

RANGE

Max RLA LRA

Min

220 24

180

207

253

COMPR

20.9

10.5

8.3

Table 2 — Electrical Data; 50DP012

OUTDOOR

FAN MOTOR

Qty

113 2

98 2

49 2.1

41

2

2 1.8

FLA

4 6

3.8

INDOOR

FAN MOTOR

FLA FLA

Hp

1 3 45

5.5

1.5
1

3 45
1 3.45
1

3 45

1 3.45 156

5.5 39 18.8

1.5

5.5 72

1.5

1.5 5.5

5.5

1.5
1 3.2

1.5 5.1
1

3.2

1

3.2

1

3 2

1.5 5.1
1 5 5.1

1.5 5.1
1 1.6

2.Ó

1.5
1 1.6
1

1 Ó

1 1.6

2.6

1 5

1.5 2.6

2.6 66

1.5
1

1 35
1 7

1 5

FACTORY INSTALLED

HEATERS

Nom Kw

_

—

39
72

117 56.1 155

117

156

— -

47 18.8 65 70
82

135

47 18.8
82 34 2

135 56.1

_

— -

21
39 32.4
66 55 0 85
21
39 32.4 55

“

--

18.8

34 2 100 90

74.8 205

34.2

56.1

74.8

—

34 2

56.1

—

17.1 30

17.1

55.5

-

POWER

Min Ckt

Amps

SUPPLY

Max Fuse

70
70 7$
70 70

• ••

70
100
155
205 175

60

60

1 10

180

65
110
180 i7d

30

35 35

55

35

90
25

25

Amps

70

1 oO

175

9>3

150

' 70'

no

35
3S

50
30
3S
50

30
25

2.5

..........

«

Compr — Compressor

FLA — Full Load Amps

Hp — Horsepower

— Locked Rotor Amps

LRA

— Rated Load Amps

RLA

• .1 Fuse only; unshaded values indicate fuses or circuit breakers
may be used

Table 3 — Electrical Data; 50DP014

VOLTAGE

VOLTS/PH/HZ

200/3/60 180 220 27.0

230/3/60 207 253 22.8

460/3/60

575/3/60

Compr — Compressor

FLA — Full Load Amps
Hp — Horsepower

RANGE

Min

414

518 632 9.3

COMPR

Max

508 11.6

LRA Qty FLA

RLA

160

137 2

69 2

55

LRA — Locked Rotor Amps
RLA — Rated Load Amps

OUTDOOR

FAN MOTOR

2 4.6

4 5

2.3

2 1 8

INDOOR

FAN MOTOR

FLA

Hp

2.0

3.0

2.0 7 4

2 0

2.0

2.0

3.0 8.4

3.0

3.0
3 0 8.4 156 74 8 210 200

2.Ò 6.6

3.0 8 4

2.0 6 6
2 0
2 0
3 0

3.0

3.0 8.4
2 0 3.3

3.0

2.0

2.0
2 0
3 0 4 2

3.0 4.2

3.0 4.2
2 0

3,0

7 4

8.4

7.4
7 4

7.4

8.4 72

8.4

6.6

6.6

8.4

8.4

4.2
3 3

3.3

3.3

2 3

3.8

FACTORY INSTALLED

HEATERS

FLA Nom Kw

__

— —

39

72 34 2 100
117
156

39

117

_ __

- -

47 18.8 70

82
135

47

82
135

__
— _

21

39
66
21

39 32.4 55
66 55 0

-

Fuse only; unshaded values indicate fuses or circuit breakers

may be used

18.8 80 90

56.1

74.8

18.8 80 ■ ■■ ■ 90

34.2 105
56 1 165 ; 75

34 2
56 1

18.8

34.2

56.1 185

_

17.1

32.4
55 0

17.1 40

-

POWER SUPPLY

Min Ckt

Amps

80 90
80 90

160
205

70
70

Max Fuse

:7L::::A8e.:A.;/

115
180

70

120 DO

35 i 40

40
35
55
90

90

30
30

Amps

LOO

150

200

: 10

Ì Ì0 .

] 75

' / J

..

SO
8C'

30 ■

40
40

60
40
50

SO

30

Table 4 — Electrical Data; 50DP016

VOLTAGE

VOLTS/PH/HZ

208-230/3/60 187 253

460/3/60 414

575/3/60 518

Compr — Compressor LRA

FLA — Full Load Amps RLA

Hp — Horsepower

RANGE

Min Max

508 32 120

632 25.6 96

RLA

61.6

COMPR

LRA

266

Locked Rotor Amps
Rated Load Amps

OUTDOOR

FAN MOTOR

Qty

FLA

2 6.6 3

2

3.3

2 2.6 3

balanced within 10%. Contact local power com
pany for correction of improper voltage or phase
imbalance. Unit failure as a result of operation on
improper line voltage or excessive phase imbalance
constitutes abuse and may cause damage to elec
trical components. Such operation would invali
date applicable Carrier warranty.

Field Control Wiring — Install a Carrier-approved

accessory thermostat assembly according to instal

lation instructions included with accessory. Locate

thermostat assembly on a solid wall in the condi
tioned space to sense average temperature.

Route thermostat cable or equivalent single

leads of no. 18 AWG colored wire from subbase

INDOOR

FAN MOTOR

Hp FLA FLA

10.4

3

4.7

3 8

*Fuse only.

FACTORY INSTALLED

HEATERS

Nom Kw

_ _

72-82
117-135 6.1 165-185 150-175
156-180

34.2 105-120

74.8

—

39
66
96

- -

32.4 55

55.0 90

79.8

POWER SUPPLY*

Min Ckt

Amps

105 125

210-240

55

130

50 45

Max Fuse

Amps

125

200-225

125

terminals thru conduit in unit to low-voltage
connections as shown on unit label wiring diagram

and in Fig. 11. Use no. 16 AWG wire for lengths
exceeding 50 feet. Set heat anticipator settings as
indicated in Table 5. Settings may be changed
slightly to provide a greater degree of comfort for a
particular installation.

Refer to accessory remote control panel in

structions 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

screen(s) must be in place before operating unit.

60
60
90

TBJ.

REMOVABLE JUMPER rr°^ I

THE RMOSTAT ASSEMBLY

Ijji-i-g ® ^ ^ [g]

ao

o cc

O Ili

(/> a

Fig. 10 — Field Power Wiring Connections

START-UP

Unit Preparation — Make sure that unit has been

installed in accordance with installation instruc
tions and applicable codes.

Compressor Mounting — On 50DP012/014 units,

compressors are internally spring mounted. Do not
loosen or remove compressor hold-down bolts. On

50DP016 units, loosen compressor hold-down
bolts until sidewise movement of the washer under
each hold-down bolt head can be obtained. Do not
loosen completely as bolts are self-locking and will
maintain adjustment.

Internal Wiring — Check all electrical connections

in unit control boxes . . . tighten as required.

Refrigerant Service Valves — Each 50DP012/014

unit system has 2 Schraeder type service ports, 1
on suction line and 1 on compressor discharge line.

Be sure that caps on the ports are tight. The

50DP016 has 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 hrs. prior to startup

Table 5 — Heat Anticipator Settings

UNIT MODEL

50DP012/014

50DP016

VOLTAGES

200/3/60

230/3/60

460/3/60

208-230/3/60

460/3/60

KW STAGE 1

13
23 8
39 1

52.0 52

17.3
31 4
51 7

15.7

29.8

50.5

23.8-31.4
39 0-51.7 52 .26

52.0-68.8

29.8
50 5 .26 .52

73.3

STAGE 2

.26
.26
.52

.26

26
52

.26
.26
.26

.26

.52

.26

.52 .52

.26
.52

.52

.52

_

26
26
52

26
26

_

.26

' ¡H É É É [g] è É'

Q <

liJ QH

I ^ 3

O > CD

gJlW-VOLT^ TS^l^ 8upq<

Z

_ DC

CD CO

Fig. 11 — Field Control Thermostat Wiring

Cooling — To start unit, turn on main power

supply. Set system selector switch at COOL and

fan switch at AUTO. Set thermostat below room
temperature.

DP012 AND DP014
No. 1 compressor starts on closure of No. 1

contact in thermostat.
Additional rise in room temperature closes contact

No. 2 in thermostat, energizing No. 2 contactor.

Second compressor starts.
DP016

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 above room
temperature. Check unit charge. Refer to Refrig
eration Charge in Service Section.

Reset thermostat at a temperature above room

temperature. Compressor(s) will shut off.
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 thermo
stat light comes on. Determine reason for safety
trip. Restart 012/014 compressor by turning ther

mostat selector switch OFF then ON. Restart 016

compressor by resetting circuit breaker at unit.

Heating — Turn on main power to unit. Set

thermostat at HEAT, fan at AUTO, and above

room temperature. First stage of electric heater

elements are energized on closing of heating

contact No. 1 in thermostat. On a further fall of

room temperature, heater contact No. 2 closes en

ergizing second stage electric heater elements.

TO SHUT OFF UNIT — Set system selector switch

at OFF.

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 35 F outdoor air temperature.

Ventilating (Continuous Fan) — Set fan and system

selector switches at ON and OFF, respectively.
Indoor air fans operate continuously to provide
constant air circulation.

I

i

Table 6 — Air Quantity Limits

#

€

UNIT MODEL T

50DP0Ì2
50DP014
50DP016

* Indoor Fan Max Watts = 3000

Automatic Changeover — The unit automatically

MIN CFM

3000
3750

—4500

MAX CFM

5000
6250

7500‘

switches from heating mode to cooling mode when
system selector switch is set at AUTO, and
temperature of the conditioned space rises to
cooling selector lever setting. When temperature of
the conditioned space falls to the heating selector
lever setting, unit automatically changes from
cooling mode to heating mode. The thermostat is
interlocked so that cooling and heating systems do
not operate at the same time.

Economizer Operation — If unit is equipped with

modulating outdoor air control (economizer), it
should operate as follows:

ENTHALPY CONTROL SETTING ^ Set enthalpy
control (Fig. 12) to desired temperature and
relative humidity which provides cooling with
outside air only (no compressor operation). To

determine appropriate setting of enthalpy control;

1. Determine maximum combination of relative
humidity and temperature of supply air con
sidered acceptable for the installation.

2. In Fig. 13, locate percent humidity on the
left-hand scale and dry-bulb temperature on the
right hand scale. Example in Fig. 13 uses 60%

RH and 66 F.

3. Draw a straight line connecting the 2 points.

4. Adjust the enthalpy control dial to the setting

indicated on control setting scale in Fig. 13.
The control setting for example conditions is
the B range.

MIXED AIR THERMOSTAT SETTING ^ Set
mixed air thermostat in return air compartment to
desired temperature of air delivered to the condi
tioned space (not less than 35 F or condensation in
unit will result). Do not uncoil mixed air thermo
stat capillary.

Cooling Season

When stage 1 is satisfied, outdoor fans, indoor
blowers and compressors shut off. Outdoor air
damper closes.

If fan switch is at ON, and stage 1 is satisfied,
outdoor air fans and compressors shut off, indoor
blowers continue to operate and outdoor air

damper stays in ventilation position.
INTERMEDIATE SEASON (Economizer Control)

— Operation is similar to cooling season except
when stage 1 of cooling thermostat closes, outdoor
air fans and compressor remain off if outdoor
enthalpy is below enthalpy control setting. Only
indoor blowers are operative. As temperature of
the mixed air (outdoor air mixed with return air)

rises above or drops below mixed air thermostat
setting, outdoor air damper modulates to maintain

mixed air setting.

Fig. 12 — Enthalpy Control Assembly

:Oi

20-

I-I

7g:v;3|

CONTROL
SETTING

e>c

% I

a:

o

s

É 50-

Z

ui .
^'60^

IÜ

O;

70r

80-

Fig. 13 — Nomograph for Determining

Enthalpy Control Setting

With the fan switch at AUTO, and the room

thermostat satisfied, indoor blowers shut off and

outdoor air damper closes. If fan switch is at ON
and room thermostat satisfied, damper goes to
ventilation position.

HEATING SEASON - Outdoor air damper always

stays in ventilation position while indoor blowers
are operating. The damper closes and the indoor
blowers shut off when the room thermostat is

satisfied.

-> Variable Volume Units — Units suitable for use

with variable volume air handling systems are

equipped with 2 electric unloaders on the com

pressor. The control panel for these units (Fig. 14)

consists of a step controller, a proportional ther

mostat, a 7-day timer and a power switch.

Before starting unit, open compressor seiwice

valves and liquid line shutoff valve. Be sure com

pressor crankcase 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.

CYCLE-LOG

STEP
CONTROLLER

PROPORTIONAL
THERMOSTAT

SEVEN
DAY

TIMER

t

Fig. 14 — Control Panel, Variable Volume Units

3. If supply air leaving unit is above 50 F (or other
field-set temperature), step controller will oper
ate 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. 15.

4. Step controller, 7-day timer and proportional

thermostat are factory set and adjusted. If other
settings or changes in adjustment are required,
refer to discussion of these items.

Seven-Day Timer Adjustment — Factory settings

are ON —6:30 AM; OFF —7:30 PM for each of
7 days.

l.On the timer dial face (Fig. 14), loosen the

thumbscrews 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 proportional ther

mostat, Fig. 14, monitors temperature of the con
ditioned air leaving unit. On signal from the
thermostat, sequence motor operates cam switches
to load or unload compressor to maintain thermo
stat setting. Thermostat is factory set at 50 F ± 6 F
but may be reset between 0° F and 100 F as

follows:

TEMPERATURE SETTING - Turn knob on front
of case until pointer indicates desired set point
temperature. This is the center point of propor
tional 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 thennostat range
(about 5 F" at a time) until system is stable.

^ 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 adjustable to operate at any point on the

160 angular degrees of cam shaft rotation. The

differential of each switch may be adjusted from a
minimum of 5 angular degrees to a maximum
limited only by the 160 degrees of camshaft

rotation.

Rotational direction is controlled by the propor
tional thermostat thru the step controller feedback
potentiometer and balancing relay.

DETERMINING SWITCH SETTINGS - Switches
are factory set at angular settings as shown on
Fig. 15 (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 propor
tional thermostat to provide desired step controller
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.

10

12 3 4

STEP CONTROL SWITCH

Fig. 15 — Step Controller Sequence

CAM ADJUSTMENTS - The step controller is
shipped with cams set to operate switches (i.e. com
pressor unloaders) as shown in Fig. 15. All switches

are closed (compressor unloaded). The shaft is

positioned all the way counterclockwise (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. 16.

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 con
troller, 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

MAKE

POIMT

St^EAX

POINT

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

jumpering 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 counterclockwise 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.

SERVICE

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.

EVAPORATOR COIL - Clean with Oakite 164 ­available from Carrier (Service Parts) under Part
No. 28GS680002.

CONDENSER COIL - Clean outdoor coil annually

or as required by location or outdoor air condi

tions. 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 heat

ing and cooling season, or more often if operating
conditions require it. Refer to Table 1 for type
and size.

OUTDOOR AIR INLET SCREENS - Clean
screens with steam or hot water and a mild deter
gent. Do not use throwaway filters in place of
screens.

Fig. 16 — Step Controller Cam Adjusting Details

(motor end view)

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
outdoor fan or indoor blower motors are required
for first 5 years of operation. Annually thereafter,
clean and repack bearings with a suitable bearing
grease.

11

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Evaporator Blower Adjustrnent — Blower motor

pulleys are factory set for speed shown in Table 1.

To change blower speed:

1. Shut off unit power supply.

2 Loosen belt by loosening blower motor mount

ing plate nuts.

3 Loosen movable pulley flange setscrew (see

Fig. 17).

4 Screw movable flange toward fixed flange to

increase speed and away from fixed flange to
decrease speed. Increasing blower speed in
creases load on motor. Do not exceed maximum
speed specified in Table 1.

See Table 6 for air quantity limits.

5. Set movable flange at nearest key way of pulley
hub and tighten setscrew. (See Table 1 for speed
change for each full turn of pulley flange.)

To align blower and motor pulleys, loosen

blower pulley setscrews and slide blower pulley
along blower shaft. Make angular alignment by
loosening motor from mounting plate.

MOVABLE a.ANG£S

STRAIGHT EDGE

MOST BE

4WRAU£L

\VWTH8ELT f\

IsETSCREWsj^^'^l

'ПХЕО FLANGES^

Si№LE-GROOve TVfO-GROOVE

MOTOR a FAR SHAFTS
MUST BE PARALLEL

Fig. 17 — Indoor Blower Pulley Adjustment

To Adjust Belt Tension — Loosen blower motor

SETSCREVVS

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. 18) 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 hub
cap to prevent hub from rusting to motor shaft.
Fill hub recess with permagum if rubber hubcap is
missing.

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).

Fig. 18 — Outdoor Air Fan Adjustment

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 terminals 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. Out
door air damper goes to fully closed position
(indoor air damper opens).

5. Adjust mechanical linkage for correct position
ing if necessary. If cooling was simulated in 2,
remove jumper and reconnect thermostat wire(s).

DAMPER VENT POSITION SETTING

1. Set fan switch at ON (continuous fan operation)
and close niglit switch if used.

2. Set system selector switch at 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. Damper to motor will

result.

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.

Refrigerant Charge — Amount of refrigerant charge

is listed on unit nameplate (also refer to 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 tech

niques. After evacuating system, weigh in the

specified amount of refrigerant. (Refer to Table 1.)
LOW CHARGE COOLING — Using appropriate

cooling charging chart. Fig. 19, 20 or 21 add refrig
erant until conditions of the chart are met. Note
that charging charts are different from ones nor
mally used. Charts are based on charging units to

12

correct superheat for various operating conditions.

An accurate pressure gage and temperature sensing
device are required. Connect temperature 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 ÚSE 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, care
fully blow some of the charge. Recheck suction
pressure as charge is adjusted.

Example: Fig. 19 — 50DP012
Outdoor Temperature

............................................

75 F

Suction Pressure....................................................65 F

Suction Temperature should be

............................

62 F

(Suction Temperature may vary ±5 F.)

If Chargemaster® charging device is used, tem
perature and pressure readings must be accom
plished using appropriate charging chart.

Fig. 20 — Charging Chart — 50DP014

20 30 40 50 60

SUCTK3N LINE TEMP F

Fig. 19 — Charging Chart — 50DP012 Fig. 21 — Charging Chart — 50DP016

70

13

20 30 40 50 60

SUCTION LINE TEMP F

70

i

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.

Book 1 4
Tab

1b 6b

Form 50DP-9SI Supersedes 50DP-3SI

Printed in U.S.A. 11-79 PC 111 Catalog No. 535-007

i