Carrier 48HDT User Manual

Carrier Corporation • Syracuse, N Y 13221

Connbination Heating/Cooling Units

INDEX

Page

SAFETY CONSIDERATIONS

INSTALLATION .......................................................1-16

Step 1 — Provide Unit Support

• ROOF CURB

• SLAB MOUNT

Step 2 — Field Fabricate Ductwork

Step 3 — Rig and Place Unit.................................... I

• POSITIONING

Step 4 — Install Flue Hood

Step 5 — Trap Condensate Drain ........................... 3

Step 6 — Install Gas Piping
Step 7 — Make Electrical Connections

• FIELD POWER SUPPLY

• FIELD CONTROL WIRING

• HEAT ANTICIPATOR SETTINGS

Step 8 — Make Outdoor Air Inlet Adjust

ments and Install Outdoor Air Hood

• OPTIONAL OUTDOOR AIR DAMPER

• OPTIONAL ECONOMIZER

Step 9 — Adjust Evaporator Fan Speed
START-UP
SERVICE

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

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

SAFETY CONSIDERATIONS

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

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

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

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

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

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

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

...........

1

1

1

3
3

3

10

16

16,17

18-22

Installation and servicing of air conditioning
equipment can be hazardous due to system pressure
and electrical components. Only trained and quali
fied service personnel should install, repair or
service air conditioning equipment.

Untrained personnel can perform basic mainte
nance functions of cleaning coils and filters and
replacing filters. All other operations should be per
formed by trained service personnel. When workiog
on air conditioning equipment, observe precautions
in the literature, tags and labels attached to the unit
and other safety precautions 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.

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INSTALLATION

NOTE: 004,005,006 size units in California require
the installation of an accessory NOx baffle. Refer to
Accessory NOx Baffle Installation Instructions for
details.

Step 1 — Provide Unit Support

ROOF CURB (Downshot Units Only) — Assemble
and install accessory roof curb in accordance with
instructions shipped with curb. Curb details and
information required to field fabricate a roof curb
are shown in Fig. 1. Install insulation, cant strips,

roofing and flashing as shown. Ductwork must he

attached to curb.

Oie^sfcehsig of the
roof cîïïh- is CFîîîcaJ ii>r wter i'aiegjtiij'. ïastaif
^pasîietîsîg ïoàtertaî. with the ccxif corb as

io L

Curb should be level. Unit leveling tolerance is

1/16 in. per linear foot in any direction. This is
necessary for unit drain to function properly. Refer
to Accessory Roof Curb Installation Instructions
for additional information as required.

SLAB MOUNT (Horizontal Units Only) — Provide

a level concrete slab that extends a minimum of 6 in.

beyond unit cabinet. The slab should be 8 in. thick
with 4 in. above grade. Install a gravel apron in front
of condenser air inlet to prevent grass and foliage
from obstructing airflow. Trap condensate drai.n.
Allow for trap when pouring slab.

Step 2 — Field Fabricate Ductwork — On

downshot units secure all ducts to roof curb and

building structure.

Insulate and weatherproof all external duct

work, 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 around

ductwork. Cabinet return air static shall not exceed

-.35in.wg with economizer or -.45in.wg without

economizer.

Step 3 — Rig and Place Unit — Inspect unit for

transportation damage. File any claim with trans
portation agency. Keep upright and do not drop.

Carrier Corporation 1984

Form 48H.L-7SI

Fig. 1 — Roof Curb Details

#

Spreader bars are not required if top crating is left
on unit. Rollers may be used to move unit across a
roof. Level by using unit frame as a reference,
leveling tolerance is ± l/16in. per linear foot in
any direction. See Fig. 2 for additional information.
Weight is shown in Table 1.

Lifting holes are provided in base rails as shown in

Fig. 2. Refer to rigging instructions on unit.

POSITIONING — Maintain clearance around and
above unit to provide minimum distance from com
bustible materials, proper airflow and service access.

See Fig. 3 and 4.

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.

Locate mechanical draft system flue assembly at
least 48 in. from any opening through which com
bustion products could enter the building, and at
least 48 in. from an adjacent building. When unit is
located adjacent to public walkways, flue assembly
must be at least 7 ft above grade.

After unit is in position, remove polyethylene
shipping wrapper and rigging skids.

Step 4 — Install Flue Hood — Flue hood and

screen are shipped screwed to the basepan in furnace
compartment. Remove from shipping location and
using screws provided, install flue hood and screen

in location shown in Fig. 3 or 4. On 48LDT004-006

units, a flue restrictor plate MUST be assembled to

the flue discharge. The plate is shipped with the flue

hood package. Install as shown in Fig. 5.

Step 5 — Trap Condensate Drain — See Fig. 3 or

4 for drain location. A 7/8-in. preformed drain hose
is shipped clamped to the indoor basepan. At instal

lation, re-route the hose so it passes through the hole

in the indoor basepan and unit base rail.

When installed properly, the hose protrudes
through the base rail one inch. Replace clamp over
the hose where hose passes through the basepan to
ensure that hose remains level. Use a trap at least
4 in. deep and provide protection for trap against
freeze-up.

Step 6 — Install Gas Piping — Unit is equipped

for use with type of gas shown on nameplate. Refer

to local building codes, or, in the absence of local
codes, to ANSI Z223.1-1980 entitled National Fuel
Gas Code.

Natural gas pressure at unit gas connection must

not be less than 5 in. wg or greater than 13.5 in. wg
while unit is operating.

Size gas supply piping for O.Sin.wg maximum
pressure drop. Do not use supply pipe smaller than
unit gas connection. See Fig. 6 for typical pipe guide
and location of external manual main shutoff valve.

For LP gas units, pressure at unit gas connection

must not be less than 12in. wg or greater than

13.5 in. wg.
A 1/8-in. NPT plugged tapping, accessible for test

gage connection, must be installed immediately up
stream of the gas supply connection to the furnace.

Step 7 — Make Electrical Connections

FIELD POWER SUPPLY

004,005,006,007 — All units except 208/230-volt
units are factory wired for the voltage shown on the

nameplate. If the 208/230-v unit is to be connected
to a 208 power supply, the transformer must be re
wired by connecting the blue wire to C-13 and the

red wire to C-DUl.

48HDD,LDD/ HD,LD008 — 230- and 460-volt

units are factory wired for the voltage shown on

nameplate. If unit will be connected to a 208 power

supply, the transformer

ing the black wire to the 200-volt lead and insulating

the 230-volt lead.

48HHD,LHD/HH,LH008 — 230- and 460-volt

units are factory wired for the voltage shown on

nameplate. If 208/ 230-voIt unit will be connected to

a 208 power supply, the transformer must be rewired

by connecting the blue wire to C-13 and red wire
to C-DUL

All Units — Refer to unit label diagram for addi
tional information. Pigtails are provided for field
service. Use factory-supplied splices or UL­approved copper/aluminum connector.

When installing units, provide a disconnect per

NEC.

All field wiring must comply with National Elec

trical Code and local requirements.

Install conduit connectors in side panel openings
indicated in Fig. 3 or 4. Route power lines through
connector to terminal connections as shown in

Fig. 7.

Voltage to compressor terminals during opera

tion must be within voltage range indicated on unit
nameplate (also see Table 2). On 3-phase units,
voltages between phases must be balanced within
2% and the current within 10%. Use the formula
shown in Table 2, Note 2 to determine the % voltage
imbalance. Contact local power company for cor

rection of improper voltage or phase imbalance.
Operation on improper line voltage or excessive
phase imbalance constitutes abuse and may cause
damage to electrical components. Such operation,
would invalidate any applicable warranty.

FIELD CONTROL WIRING ^ Install a Carrier­approved accessory thermostat assembly according
to installation instructions included with the acces
sory. Locate thermostat assembly on a solid wall in
the conditioned space to sense average temperature.

must be rewired by connect

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Fig. 2 — Rigging Details

Table 1 — Physical Data

UNIT SIZE 48 SERIES 004
OPER WT (lb)

Unit

with Economizer

Roo f Curb 130 130

COMPRESSOR

Qty Type
Oil (oz)

REFRIG (R-22) Capillary Contre

Cha rge (lb) 61

COND COIL

Row s
Fins/in 170
Total F ace Area (sq ft) 6 3

COND FAN

Nom Cfm 2200 3100
Qty Diam (in ) 1 22
Motor Hp
Motor Rpm

EVAP COIL

Row s 2 2
Fins/in
Total F ace Area (sq ft) 5 33 5 33

EVAP FAN

Qty Size (in ) 1 10x10 1 10x10
Type
Nom Cfm
Motor Hp Std

Nom M otor Rpm
Std/Opt Low 800/ 890

Rpm Range Std

Motor Pulley
Pitch D iam
(in )

Fan Pulley
Pitch D iam
(in )

Belt. Q ty Type. Length (in
Speed Change per Full

Turn of Moveable

Pulley Flange (Rpm )
Moveable Pulley

Max Full Turns
from C losed Position

Factory Setting Std
Full Turns Open Opt

Factory Speed Setting Std
(Rpm) Opt

FUR NACE SECTION

Tem p Rise (F)
Heating Input (Btuh)
Output Cap (Btuh)

Burner Orifice D iam

(in . drill size)

Natural Gas
Pilot Orifice Diam

(in drill size)
Natural Gas

Thermostat Heat Anticipator

Setting 460 v

HIG H-PRESS SWITCH

Cutout (psig)
Reset (psig)

LOW -PRESS SW ITCH

(Suction Line)
Cutout (psig)
Reset (psig)

AIR INLET SCREEN S

Qty. Size (in )

RETURN AIR FILTERS

Qty Size (in )

High

208/230V

LDT

630

655

1 M4023E

42

2

%

850 1075

140 140

DD DD

1200 1500

Opt 3/4

'/3

— —

850/1050 1000

—
— —

LDT HDT

30-60
80,000
61,600

Std
Opt

Std
Opt

Std
Opt

Opt

005 006

HDT ] LDT HDT LDT HH

650 630

675 1 655 685 665

1 P53260 1 P6026B 1 P60-6- 1 P77

66

660

640 660 640 720 720

130

66

48 72 7 2 I 9 3 99

2

170 140

6 3

1 22 1 22

’/2 ’/2

3/4

— —

890 1000

—

35-65

120,000

92,400

LDT HDT

30-60
80,000
61,600

9 73 9 73 108 15 6

3800

1075 1075 1075 1075

140 140 140 13 9

5 33

HDT LDT

1 11x10

35-65

1 20,000

92,400

1 11x10 1 11x10 1 11x10 1 11x10 1

DD DD BD

2000 2000

1

—

1130 1050/1130

— —

—

3/4

1

—

890/1000

—

LDT HH

30-60
80,000
61,600

1 2
1 0

27 ± 4
67 ± 7

1 32x19xV2

1 16x25x1

1...20x25x1

006

LH

— —
— —

74 74

Copper Tube, Aluminum Plate Fins

Copper Tube, Aluminum Plate Fins

2 : 2

14 0 140 139

Propeller Type

3800

1 22 1 22 22

’/2 '/2

3 A

5 33 6 3 8 2

HH LH

DD

2000

’/2

3/4

1725

__

—

630- 960
796-1130

1 9-2 9
2 4-3 4

5 2
5 2

66
66

830
995

35-65

120,000

92,400

2

2

2000

3/4

1 1

_

890/1000

1050/1130

-

—

LH HD

30-60
80,000
61,600

007

HD HH

745
130

_

—

HD.HH

890
950 (HD)
125 (HD)

008

946 (LD)
125 (LD)

1 Hermetic

124

LD.LH

886

4000

BD

2200

3/4

1725

796- 130 838-1032 (@ 2 turns open)

930-1260 352-11 27 (@ 1 turn open)

2 4-3 4
2 8-3 8

5 2
5 2

1 A 43

66

66

2
2

995

35-65

120,000

92,400

113 0

120,000

HD.HH LD.LH

HH

35-65

92,400

35-65
203 ,000
160 ,370

132 29 113 33 132 29

036 64 033 66

15-45

114 ,000

91,200

008

HDD.H LD

945 941

1005(HDD)

125 (HDD)

2 P46

6 2 per system

4500

’/2

3

12x12
BD

3000

1 0

1 5

—

_

—

2 4-3 4
2 4-3 4

50
5 0

65
69

4

4Y2

907
885

HHD.HDD LDD.LHD

35-65

203 ,000

160 ,370

036 64

1 2
1 0

426 ± 7
320 ± 20

27 ± 4
67 ± 7

2 16x20x1
2 20x20x1

124

LDD.LHD

996 (LDD)

125 (LDD)

15-45

114 ,000

91,200

113 33

033 66

#

DD — Direct Drive

-----

------

■■ . •* .*

Fig. 3 — Downshot Base Unit Dimensions

Fig. 4 — Horizontal Base Unit Dimensions

Fig. 5 — Flue Hood Details;

48LDT004-006 Units

BLK-

*NPT plug is field supplied
NOTE Follow all local codes

Fig. 6 — Gas Piping Guide

-YEL

-i?

FIELD POWER SUPPLY

'“dTsconnectI

230-1-60 u_PifLNJc_l

004,005,006,007 UNITS

BLK

TO

COMP

208/230-3-60 (SEE NOTE)

■ YEL •

BLU-

FIELD POWER SUPPLY

I

I

I

44

roTsCONNECT"!

PER NEC

004,005,006,007 UNITS

I

-------

I

I—dn

I

H--------

EQUIP

GND

UM

EQUIP

GND

TO INDOOR

FAN CONTACTOR

BLK •

■ YEL ■

-BLU-

FIELD POWER SUPPLY

008 UNITS

I

I

I

-+

Ti^sconne'ct”!

I

PER NEC

EQUIP

--Q®]

I

H--------

I

GND

■ Factory Wiring
. Field Wiring

NOTE If connected to 208-v power supply, rewire unit transformer
no 1 by

1 Connecting blue wire from transformer no 1 to C-13

2 Connecting red wire from transformer no 1 to C-DUl

Fig. 7 — Power Wiring Connections

8

Table 2 — Electrical Data

UNIT

48 SERIES

LDT004

HDT/LDT005

HDT/LDT006

LH006

HH006

HD/HH

007

HD.LD/

HH.LH

008

HDD.LDD/
HHD.LHD

008

VOLTAGE

VOLTS-PH-HZ

208/230-1-60

208/230-3-60 187 254

460-3-60 414
208/230-1-60 197 254
208/230-3-60 187 254

460-3-60

575-3-60 517

230-1-60 207 254

208/230-3-60 187 254

460-3-60 414 508

575-3-60 517

230-1-60 207 254

208/230-3-60 187 254

460-3-60 414

575-3-60 508 623

208/230-3-60 187 254

460-3-60

575-3-60 518 632
208/230-3-60 187 254

460-3-60 414

575-3-60 518 632

208/230-3-60 187 254

460-3-60

RANGE

Min Max RLA LRA

254

197

508 7 6

414

508
633

633

508

414

508

508

414

508

COMPR

22 2 100 1 2 2

15 1 100 1 22

28 1 106 1

18 3 105

9 2 35 1
8 3 41

28 5

20 9

104

8 3 41

28 5

20 9

104

8 3

26 7

12 1

9 6

32 5

15 2 91 1

15 8
15 2

(ea)

7 2

(ea)

OUTDOOR

FAN MTR

Qty FLA

36 5 1 1 1

1

1 2 9 75

130 1

98 1 2 9

49 1

1

130 1

98 1

49 1

41 1

137 1

69 1

51 1 2 9 1 00

183

1 2 9

1 1 5

73 3 1

80

1

(ea)

35

1

(ea)

29
29

1.5

29

1 5

29

29

29

1 5

29

29

1 5

1 5

29

1 5

INDOOR

FAN MTR

FLA

Hp

33753 6

33'^
75

"33
.75

75 6 9 .90
75

.75 3 5 .57

75

1 006980

75

1 00

75

1 00

75

1 008069

50

75
50

75
50753 5

507569

75

1 00

75

1 00

1 0
1 5

1 0
1 5

1 0

1.5
1 0

1 5
1 0

1 5

69
3 6

6 9

3.5

6 9

6 9

69
80

3 5

40

69
80

69
80

40

80
3 6

48

1 8

2 4
7 5
5 4

6 0
2 7

3 0
1 4

2 1

48

6 5
24

33

COMBUSTION

FAN MTR

FLA

90

90

57

.90 35

90 19
90

90 40/40

57

90 30

90

90 40/40

57

90 30

90

57
90 22 4
90

57

57

90

57

MCA

30/30

50/50 60/60

POWER SUPPLY

MOCP (Amps)*

40

15

46

20

55

20

55

20

40
42

18 5
19 5

25
25

26
43

45
21

22

50

45/45

25
60

45/45

25
20

50

45/45

25

45

50

45/45

25

45

60

30
30

35
35

40
50

50
25

25

#

FLA — Full Load Amps
LRA — Locked Rotor Amps
MCA -- Min imum Circuit Amps (for wire sizing) Complies with

NOTES
1 In compliance with NEC requirements for multimotor and

2 Unbalanced 3-Phase Supply Voltage

NEC, Section 430-24

combination load equipment (ref NEC Articles 430 and 440),
the overcurrent protective device for the unit shall be fuse only

Never operate a motor where a phase unbalance in supply volt
age IS greater than 2% Use the following formula to determine

the % voltage unbalance

% Voltage Unbalance

= 100 X-

max voltage deviation from average voltage

average voltage

Supply voltage is 460-3-60

AB = 452 volts
BC = 464 volts
AC = 455 volts

Average Voltage

452 + 464 + 455

1371

3

457

MOCP — Maximum Overcurrent Protection
RLA — Rated Load Amps

'Fuse only

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 unbalance

% Voltage Unbalance = 100 x = 1 53%
This amount of phase unbalance is satisfactory as it is below

the maximum allowable 2%

457

iMPORTAKT' if

ffsofe

THERMOSTAT

Factory Wiring

---------

Field Wiring

Fig. 8 — Control Wiring Connections

Route thermostat cable or equivalent single leads
of colored wire from subbase terminals through con
nector on unit to low-voltage connections as shown
in Fig. 8.

NOTE: For wire runs up to 50ft, use no. 18 AWG

insulated wire (35 C mininum). For 50 to 75 ft, use

no. 16 AWG insulated wire (35 C minimum).

Pass the control wires through the hole provided
in the corner post; then feed wires through the race
way built into the corner post to the 24-v barrier

located on the left side of the control box.

HEAT ANTICIPATOR SETTINGS — Set heat

anticipator settings at 1.20 for 460-voIt units and

1.00 for 208/ 230-volt units. Settings may be changed
slightly to provide a greater degree of comfort for a
particular installation.

Step 8 — Make Outdoor Air Inlet Adjustments and Install Outdoor Air Hood

OPTIONAL OUTDOOR AIR DAMPER

48HDT,LDT004,005,006 and HD007 — Optional

outdoor air damper is shipped with hood broken

down inside of unit. See Fig. 9.
Assembly

1. Remove filter access panel.

2. Remove sheet metal parts from filter area.

3. Using screws provided, a.s.semble sides to the
inside of the hood. See Fig. 9.

4. Discard baffle.

5. Install damper blade by inserting threaded pins

through hole in side plates.

6. Use wing nuts provided to hold blade in place.

7. Install outdoor air hood assembly, using screws
provided.

8. Install outdoor air inlet screen and screen
retainer.

9. Replace access panel.

Fig. 9 — Outdoor Air Damper and Hood

Installation and Details
(004,005,006.007 Units)

Fig. 10 — Access Panel Location

(008 Units)

lO. Loosen wing nut on side plate to adjust blade.

Adjust damper blade to desired setting for out

side air intake.

48HD,LD/ HDD,LDD008 — Optional outdoor air
damper is shipped with hood broken down in unit
filter section. See Fig. lO.

Assembly

1. Remove protective cover from unit. See Fig. lO.

2. Remove upper filter aecess panel (save screws).
See Fig. lO.

3. Remove hood parts from unit evaporator fan
and filter area. Assemble hood top and side
plates as shown in Fig. 11. Do n ot atta ch hood

to u ni t a t th is tim e .

4. Adjust outdoor air damper blade to desired
setting for outside air intake by releasing linkage

rod setscrew and adjusting linkage rod. See
Fig. 12. Secure damper blade in desired position
with setscrew.

5. Remove screws holding manual outdoor air
damper to unit. See Fig. 13.

lO

Install outdoor air hood assembly, using screws
from step 5. These screws secure the manual
outdoor air damper assembly and the outdoor
air hood to unit. See Fig. 13.

7.

Slide outdoor air inlet screens into screen tracks

on hood side plates. While holding screens in

place, fasten screen retainer to hood using screw

provided. Make sure bottom edge of screens rest

inside base rail as shown in Fig. 14.

Replace upper access panel with screws saved

from step 2.

Fig. 11

Outdoor Air Hood Details

(008 Units)

MANUAL OUTDOOR
AIR DAMPER ASSEMBLY

!»>•■ LINKAGE ROD BLADE

LINKAGE
ROD SETSCREW

Fig. 12 — Damper Blade Adjustment

(008 Units)

Fig. 14 — Outdoor Air Hood Installed

(008 Units)

<2> ®

0

0

0

(rXjF^

0

0

0

0

0

m

6RN/YEL

1

1

TBI

C — Contactor Compressor
CLO — Compressor Lockout
IDR — Induced Draft Relay
IFC — Indoor Fan Contactor

_ _

(D ®
<2> ®

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TRAN^

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<n> <®

o@o

® <§>

XCLO
(D

(D

LEGEND

<n> <Ì3>

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FUSE-

IFR — Indoor Fan Relay
TB — Terminal Block
TDR — Time-Delay Relay
TRAN — Transformer

Fig. 15 — Control Box Details

(008 Units)

EQUIPMENT
GROUND

Viol

a

Fig. 13 — Manual Outdoor Air Damper

(008 Units)

OPTIONAL ECONOMIZER
48HDT,LDT004.005.006/ HD007

1. Remove upper filter access panel (save screws).
See Fig. \b.

2. Remove economizer hood parts from unit filter
area, and assemble leaving out the damper
blade. See Fig. 17. Remove tape from baro

metric relief damper.

3. Remove indoor blade linkage retaining strap
(Fig. 18). Place washer on linkage rod supplied
with accessory. Place linkage rod into hole “B”

of outdoor damper blade. Secure rod with blue
retaining clip provided.

11

4. Remove mixed air thermostat (MAT.) capillary
retaining strap and stretch capillary through
notch in filter support. See Fig. 19. Route
through hook on upper left side of indoor coil
and secure end of capillary to retainer on lower
right side of indoor coil.

5. Fasten baffle to left side of damper plate with
round head screws provided. See Fig. 19.

6. Set vent position of damper by turning base unit
power on and allowing only the indoor fan to
run. Adjustment is made on left side of damper
motor by loosening vent position setscrew and
moving vent position lever back towards indoor
coil to CLOSE DAMPER or forward to OPEN

DAMPER. Once adjustment is made, retighten
setscrew and turn indoor fan off.

HOOD

UPPER FILTER

ACCESS PANEL

ACTUATOR
MOTOR

LINKAGE ROD

RETAINING STRAP

INDOOR DAMPER BLADE

Fig. 18 — Removing Indoor Blade Linkage

Retaining Strap (004,005,006,007 Units)

OUTDOOR AIR

INLET SCREEN

AIR SCREEN
RETAINER

Fig. 16 — Removing Economizer Upper Filter

Access Panel (004,005,006,007 Units)

DAMPER FILTER
MOTOR SUPPORT

• BAROMETRIC
RELIEF DAMPER

NOTCH

BASE UNIT
RECEPTACLE

Fig. 19 — Economizer

(004,005,006,007 Units)

7. Remove 4 screws holding economizer to unit.
Use screws to fasten hood to front of econo

mizer section.

MIXED AIR
THERMOSTAT
CAPILLARY

Fig. 17 — Economizer Hood Installation

and Details (004,005,006,007 Units)

8. Remove tape from outdoor air thermostat

(OAT.) and cooling lockout switch (CLS), and
fasten to inside of the hood with screws and
speed clips provided. See Fig. 20. Place knob,

12

supplied with accessory, on OAT. and set for 3 F
below indoor room thermostat setting.

If accessory enthalpy control is used in lieu of
OAT., refer to instructions shipped with
accessory.

9. Place outdoor air inlet screen in hood and
secure with retaining bracket across hood front.

See Fig. 16.

10. Replace upper filter access panel with screws
saved from step 1.

POWER FAILURE — Dampers have a spring
return. In event of power failure, dampers close
until power is restored. Do not manually operate
damper motor.

48HD,LD/ HDD,LDD008 — Optional economizer

is shipped with hood broken down in unit filter

section. See Fig. 21.

Fig. 22 — Outdoor Air Hood Details

(008 Units)

#

SPEED CLIPS

OUTDOOR AIR THERMOSTAT
OR ENTHALPY CONTROL

OUTDOOR AIR HOOD SIDE PLATE

Fig. 20 — Enthalpy Control Position

(004,005,006,007 Units)

COOLING
LOCKOUT
SWITCH

(CLS)

BAROMETRIC RELIEF
DAMPER LOCATION

CLS — Cooling Lockout Switch
EC — Enthalpy Control
OAT — Outdoor Air Thermostat

BASE UNIT
RECEPTACLE

OUTDOOR AIR
INLET SCREENS (2)

Fig. 23 — Economizer Installed in Unit

(008 Units)

Assembly

1. Remove protective cover from unit. See Fig. 21.

#

Fig. 21 — Access Panel Location

(008 Units)

2. Remove upper filter access panel (save screws).
See Fig. 21.

3. Remove hood parts from unit evaporator fan
and filter area. Assemble hood top and side
plates as shown in Fig. 22. Remove tape from
barometric relief damper (see Fig. 23). Do not

atta ch hood to unit at this tim e. Put aside

baffle, screen retainer and retainer screw for
later assembly.

13

DRIVE
SHAFT

OUTDOOR BLADES (2)

MOTOR

ACCESS
HOLE

^FOR VENT
¡^POSITION
i SETSCREW

BAFFLE

ECONOMIZER ASSEMBLY

OUTDOOR DRIVE LINKAGE

Fig. 24 — Economizer Details (008 Units)

PINK WIRE

VIOLET WIRE

TERMINAL D

Fig. 25 — Economizer Motor Connections

(008 Units)

4. Determine if vent air is required in building to
be conditioned. If so, check for percentage of

vent air needed and record quantity for vent

adjustment in step 11.

5. Remove jumper plug from base unit receptacle
and discard. Insert economizer plug into recep-

. tacle. See Fig. 23.

Steps 6 through 8 involve releasing and adjust
ing indoor damper blades from factory set
position.

6. Release indoor blades drive linkage by loosen
ing linkage connector setscrew at indoor crank­arm on drive shaft. See Fig. 24.

Remove pink wire from economizer damper
motor terminal D and temporarily tape bare
wire end.

Remove violet wire from economizer damper
motor and connect to terminal D on economizer
damper motor. See Fig. 25.

7. Jumper red (base unit 24-v power) and black
wires in 24-volt control box compartment. See

Fig. 10 and 12.

DAMPER PLATE

BASE RAIL

Fig. 26 — Baffle Installation Details

(008 Units)

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

iiSiSKiSSi

Fig. 27 ~ Vent Position Setting Details

(008 Units)

Turn on base unit power to energize evaporator
fan. The economizer’s outdoor blades should
open completely.

8. Adjust the indoor blades drive linkage so that
indoor blades are fully closed. Tighten the

linkage connector setscrew. Turn off base unit
power. Reconnect pink and violet wires to
economizer motor, as shown in Fig. 25.

9. If vent air is required, leave red and black wires

jumpered. If vent air is not needed, remove
jumper between red and black wires.

10. Fasten baffle to left side of damper plate with
round head screws provided. See Fig. 26.

11. If vent air is not required, go on to step 12. If
vent air is required, proceed as follows:

a.b.Turn on base unit power. This energizes the

evaporator fan motor.

Slide economizer out of unit so that access
hole to vent position setscrew is visible. See

Fig. 27.

#

14

- " ■■ 'OUTDOOR AIR VhERMOSTAT

' (TERMINALS ARE UP)

il:TERMINALS :;i-:;Sv TTyT,;'

&s;i® COOLING lockout

.................................i SWITCH

iismM

c. Adjust vent opening by loosening vent posi

tion setscrew on left side of economizer
damper motor and setting vent position
lever to adjust damper (see Fig. 27). Move
vent position lever back toward evaporator
coil to close damper or forward to open
damper. When adjustment is completed,
retighten setscrew.

d. Turn off base unit powerand removejumper

from red and black wires.

e. Slide economizer assembly back into unit.

12. Remove tape from outdoor air thermostat
(OAT.) and cooling lockout switch (CLS), and
fasten to inside of hood with screws and speed
clips provided. Make sure terminals on OAT.
are up. See Fig. 28.

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

•v\ ENTHALPY

. ! CONTROL\

ACCESSORY

I

CONTROL

>:¥

COOLING
LOCKOUT

v‘ X'^ SWITCH

HOOD

HOOD

Fig. 29 — Economizer and Outdoor Air Hood

Assembled to Unit (008 Units)

13. Fasten hood top and side plate assembly
(Fig. 29) and economizer to unit with screws
supplied. Before attaching, make sure bottom
of hood assembly is resting on top of unit base
rail.

14. Place knob supplied with accessory economizer
on OAT. See Fig. 28. Set for 3 degrees below
indoor room thermostat setting.

If accessory enthalpy control (EC) (Fig. 28) is
used in lieu of OAT., refer to instructions
shipped with accessory enthalpy control .for
installation and adjustment.

15. Connect OAT./EC and CLS per unit label.

See Fig. 30.

Connect 2 economizer wires to each switch
with quick-connects. Unit connecting wires are
shipped taped on outdoor blade. See Fig. 23.

16. Slide outdoor air inlet screens in hood screen
tracks. Secure screens with screen retainer

across hood front. Secure screen retainer with
screw provided. See Fig. 29.

Fig. 28 — Outdoor Air Thermostat/Enthalpy

Control and Cooling Lockout Switch

Installation (008 Units)

17. Replace upper filter access panel with screws
saved from step 2.

18. Turn base unit power on.

15

PINK

CLS

SEE NOTE

EC

¡—0O^t5(3>-

PINK

RED

CLS — Cooling Lockout Switch
EC — Enthalpy Control
OAT. — Outdoor Air Thermostat

NOTE: When enthalpy control (EC) is installed, outdoor air thermo
stat (OAT ) is removed from economizer

Fig. 30 — Wiring Connections for Outdoor Air

Thermostat/or Enthalpy Control and

Cooling Lockout Switch (008 Units)

Step' 9 — Adjust Evaporator Fan Speed — On

! ^ OAT „

BLUE ■

48HDT,LDT004,005,006 and 48LH006 units, the
evaporator fan motor factory speed setting is shown

on label diagram affixed to base unit. If other than
faetory setting is desired, refer to label diagram for
motor reconnection.

On 48H H006 and all 007 and 008 units, fan motor

pulleys are factory set for speed shown in Table 1.

To change fan speeds:

1. Shut off unit power supply.

2. Loosen belt by loosening fan motor mounting
plate nuts.

3. Loosen movable pulley flange setscrew (see
Fig. 31).

4. Screw movable flange toward fixed flange to in
crease 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.

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 fan and motor pulleys, loosen fan pulley
setscrews and slide fan pulley along fan shaft. Make
angular alignment by loosening motor from mount
ing plate.

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.

Fig. 31 — Indoor Air Fan Pulley Adjustment

START-UP

Unit Preparation — Make sure that unit has been

installed in accordance with installation instructions
and applicable codes.

Return Air Filters — Make sure 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.

Compressor Mounting — Compressors are inter

nally spring mounted. Do not loosen or remove
compressor holddown bolts.

Internal Wiring — Check all electrical connections

in unit control boxes. Tighten as required.

Refrigerant Service Valves — Each unit system

has 2 Schrader type service ports, one on the suction
line and one on the compressor discharge line. Be
sure that caps on the ports are tight.

Cooling — To start unit, turn on main power

supply. Set system selector switch at COOL and
fan switch at AUTO. Adjust thermostat to a setting
below room temperature. Compressor starts on

closure of contactor.

Check cooling effects at a setting above room
temperature. Check unit charge. Refer to Refrig
erant Charge in Service section.

Reset thermostat at a position above room tem
perature. Compressor will shut off.

TO SHUT OFF UNIT — Set system selector switch
at OFF position or reset thermostat at a position
above room temperature. Units are equipped with
Signal-LOC™ protection device. Unit shuts down on

#

L

16

any safety trip, and indicator light on thermostat

comes on. Check reason for safety trip.

Compressor restart is accomplished by manual
reset at the thermostat by turning the selector switch
to OFF and then to ON.

Heating

1. Purge gas supply line of air by opening union
ahead of gas valve. When gas odor is detected,
tighten union and wait 5 minutes before
proceeding.

2. Turn on manual gas valve and unit electrical
supply.

3. Set system switeh selector at FI EAT and fan

switch at AUTO, or ON. Set heating temperature
lever at above room temperature.

4. The induced draft combustion air fan will start.

Pilot lights within 30 seconds. Refer to Service,
Pilot Light if pilots do not light.

5. Main gas valve will open and main burners ignite
within 2 minutes from the pilot light ignition.
Natural gas burners are factory adjusted and
should burn with a soft blue flame. Flame should
not lift off burner face. Refer to Service, Main
Burners, if required.

6. Adjust airflow to obtain a temperature rise with
in the range specified on the unit nameplate.

TO SHUT OFF UNIT — Set system selector switch
at OFF or set heating selector lever below room
temperature.

Safety Relief — A soft solder joint at the service

Schrader port provides pressure relief under
abnormal temperature and pressure conditions.

Ventilation (Continuous Fan) — Set fan and sys

tem selector switches at ON and OFF, respectively.

Indoor air fan operates continuously to provide

constant air circulation.

Economizer Operating Sequence

COOLING MODE — When there is no power
applied to the indoor fan motor, the outdoor
damper is closed.

If outdoor ambient temperature is above the
outdoor air thermostat (OAT.) setting, the OAT.
contact is open. No power is supplied to DR2. Upon
a first-stage call for cooling, the indoor and outdoor
fans and compressor energize. The economizer

goes to vent position.

If outdoor ambient temperature is below the
outdoor air thermostat (OAT.) setting, the OAT.
contact is closed and power is supplied to DR2
(normally open contacts close and normally closed
contacts open). Upon a first-stage call for cooling
through Y1, power goes through contacts 4 and 6 of

DR2 causing DRl to energize (normally open con
tacts close and normally closed contacts open). The
economizer switches from vent or closed position

to modulation mode.

Modulation is accomplished by using the mixed

air thermostat (MAT.) in conjunction with the stall

circuitry inside the actuator. If the mixed air
temperature is above the MAT. setting, C-Tl and

C-T2 are made causing the damper motor to open
(which causes the air temperature to fall). As the
mixed air temperature falls to the MAT. setting
(54 L), C-T2 opens causing the motor to stall. When
mixed air temperature goes 4L below the MAT.
setting, C-Tl opens causing the spring to close the
damper. This in turn raises the mixed air tempera
ture and causes C-Tl to again stall the motor into
a less than full open position. If over-shoot should
occur, this process would oscillate a few times until
the mixed air temperature stabilizes.

Upon a second-stage call for cooling through Y2,
power goes through contacts 1,3 and 5 of DR2 and
CLO and the compressor is energized. Mechanical
cooling is integrated with economizer cooling.

Economizer continues in modulation mode.

When outdoor ambient temperature goes below
50 E, the cooling lockout switch (CLS) opens and

mechanical cooling is locked out.

An economizer control thermostat (ECT) on the

evaporator coil guards against abnormally low

suction temperatures while operating mechanical
cooling in conjunction with economizer. Low
suction temperatures can lead to frost on the evap
orator coil. If frost buildup is detected, thermostat
de-energizes economizer, thus closing the outdoor
air damper. This raises air temperature entering the
evaporator coil and melts frost. Once frost is melted,
the economizer is re-energized.

When cooling load is satisfied, the damper motor
is de-energized causing the spring to close the
damper.

During unoccupied periods, if a field-supplied
night switch is used and is opened, the outdoor
air damper closes.

HEATING MODE — With no power applied to the
indoor fan motor, the outdoor air damper is closed.

Upon a call for heat through Wl, the indoor fan
contactor is energized and provides power to the
indoor fan motor and economizer.

If the night set-back switch is closed, the outdoor
dampers will open to the manually preset vent
position by power passing through contacts 1 and 2
of DR 1 and goingto switches SW1 and SW2through
terminal XV of actuator. The switches are set with
3 degree angular difference between each other,
acting as a dead spot or stall region. Thus, if the
damper is below vent position, SW2 is closed power
ing the damper open until SWl closes and SW2
opens which stalls the motor. If the damper is too far
open, both SWl and SW2 are open causing the

spring to close the damper until SWl closes, again
stalling the motor.

When heating load is satisfied, the damper motor
is de-energized causing the spring to close the
damper.

During unoccupied periods, if a night set-back
switch is used and opened, the damper closes.

17

SERVICE

Cleaning — Inspect unit interior at the beginning

of each heating and cooling season or as operating

conditions require.
EVAPORATOR COIL

1. Turn unit power off. Remove indoor fan motor
access panel.

2. Diseonnect indoor motor wiring from main
control box.

3. Remove screws from base of fan motor housing.

4. Slide fan motor housing out of base unit.

5. Clean coil using a commercial coil cleaner
(i.e., Oakite 164) or dishwasher detergent in a

pressurized spray canister. Wash both sides of

coil and flush with clean water. For best results,

backflush toward return air section to remove

foreign material. Flush condensate pan after

completion.

6. Reinstall fan motor housing, reconnect wiring
and replace indoor fan motor access panel.

Fig. 34 — Separating Coil Sections

CONDENSER COIL — Inspect coil monthly.
Clean condenser coil annually, or as required by
location or outdoor air conditions.

Fins are not continuous through coil sections.
Dirt and debris may pass through first section,
become trapped between the 2 rows of fins, and
restrict condenser airflow. Shine flashlight through
coil to determine if dirt or debris has collected
between coil sections.

Fig. 32 — Cleaning Condenser Coil

Clean coil as follows:

1. Turn off unit power.

2. Remove top panel screws on condenser end of

unit. Remove screws from coil side of coil center
post. Do not remove center post.

3. Remove condenser coil corner post. See Fig. 32.

To hold top panel open, place coil corner post

between top panel and center baffle. See Fig. 33.

4. Remove device holding coil sections together at

return end of condenser coil. Carefully separate

the outer coil section 3 to 4 in. from the inner coil

section. See Fig. 34.

5. Use a water hose or other suitable equipment to

flush down between the 2 coil sections to remove

dirt and debris. Clean the outer surfaces with
a stiff brush in the normal manner.

»

6. Reposition the outer coil section, remove the coil

corner post from between the top panel and
center baffle. Secure the sections together. Install
the coil corner post, coil center post and replace
all screws.

CONDENSATE DRAIN — Check and clean each
year at start of cooling season. In winter, keep drain

and trap dry or protect against freeze-up.

Fig. 33 — Propping Up Top Panel

FILTERS — Clean or replace at start of each heat
ing and cooling season, or more often if operating
conditions require it.

OUTDOOR AIR INLET SCREENS (Downshot

Units) — Clean screens with steam or hot water
and a mild detergent. Do not use throwaway filters
in place of screens.

18

TO USE COOLING CHARGING CHART ^
Take the outdoor ambient temperature and read the
suction pressure gage. Refer to chart to determine
what suction temperature should be. If suction tem
perature is high, add refrigerant. If suction tempera
ture is low, carefully blow some of the charge. Re
check the suction pressure as charge is adjusted.

Example; (Fig. 40)
Outdoor Temperature

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

85 F

Suction Pressure............................................. 70 psig

Suction Temperature should be............................52 F

(Suction Temperature may vary ± 5 F.)

Fig. 35 — Condenser Air Fan Adjustment

Lubrication

COMPRESSORS — Each compressor is charged
with correct amount of oil at the factory.

FAN MOTOR BEARINGS — No lubrication of
condenser or evaporator fan motors is required for
first 5 years of operation. Annually thereafter, clean
and repack bearings with a suitable bearing grease.

Condenser Air Fan Adjustment (Fig. 35) — Shut

off unit power supply. Remove condenser fan

assembly (grille, motor, motor cover and fan) and

loosen fan hub setscrews. Adjust fan height as

shown in Fig. 35. Tighten setscrews and replace

condenser fan assembly.

Manual Outdoor Air Damper (Downshot Units

Only) — If outdoor air damper blade adjustment is

required, see Optional Manual Outdoor Air

Damper Section.

Economizer Adjustment (Downshot Units) —

Refer to Economizer section under Installation.

Refrigerant Charge — Amount of refrigerant

charge is listed on unit nameplate (also refer to
Table 1). Refer to Carrier Standard Service Tech
niques Manual, Chapter 1, Refrigerants.

Unit panels must be in place when unit is oper

ating during charging procedure.

NO CHARGE — Use standard evacuating tech
niques. After evacuating system, weigh in the speci
fied amount of refrigerant. (Refer to Table 1.)

LOW CHARGE COOLING — Using Cooling
Charging Chart, Fig. 36 through 41, vary refrigerant
until the conditions of the chart are met. Note the
charging chart is different from type normally used.
Chart is based on charging the units to the correct
superheat for the various operating conditions.
Accurate pressure gage and temperature sensing
device are required. Connect the pressure gage to the
service port on the suction line. Mount the tempera
ture sensing device on the suction line and insulate it
so that outdoor ambient temperature does not affect
the reading. Indoor air cfm must be within the
normal operating range of the unit (maximum 3750;

minimum 2250).

(A

<

O

g 620-

o 90

Ql

O

=i

^ 551

iii

tr

§483

iij
L.

: 345

276

207 30

80

60

50

20 30

40 50 60 70

SUCTION LINE TEMPERATURE (F)

-I 4 10 16 21
SUCTION LINE TEMPERATURE (C)

Fig. 36 — Cooling Charging Chart;

48LDT004

<

w620

<

0.

o

80

551

] 483

? 70

^414

:345-

276-

207 30

60

50

40

20 30

40 50 60 70

SUCTION LINE TEMPERATURE (F)

-I 4 10') 16 21
SUCTION LINE TEMPERATURE (C)

Fig. 37 — Cooling Charging Chart;

48HDT,LDT005

OUTDOOR TEMP

(F) (C)
115 46

105 41

95 35
85 29
75 24

1 1 1 1

65 18

(F) (C)
115 46

105 41

1 1 1 1 1

Mi tr

95 35

Mill

85 29

75 24

1 1 1 1 1

65 18

19

- -

"414--' 60

207- 30

nilTnnnR

115 46

1 1 1 1

lOf 41

80

50

20

SUCTION LINE TEMPERATURE (F)

-7
SUCTION LINE TEMPERATURE (C)

30 40 50 60 70

-1 4 lb 16 21

IMI

9£ 35

4__L_U_

1 1 1 1

05 29

il 24

65 IB

III!

55 13

Fig. 38 — Cooling Charging Chart;

48HDT.LDT006; HH.LH006

TEMP

689

(/)

< 621

o

CO

s

0552

liJ

^483

cc

0-414

z345

O

’276-

207- 30

100

90

: 80

70

60

50

40

SUCTION LINE TEMPERATURE (0 )

- -

-

-

-

-

-

-

--

-

-

SUCTION LINE TEMPERATURE ( F)

-

20 30 40 50 60

-7 -Ì 4 lb 16

OUTDOOR TEMP

­70 80

21

Fig. 40 — Cooling Charging Chart;

48HD.LD,HH.LH008

(F) (C)
115 46

105 41

95 35

85 29

75 24

65 18

55 13

45 7

- -

#

27

689

^552

r)

UÌ

llJ

(E

“-483

414

345

276

100

OUTDOOR TEMP

m 90

80

70

3 60

50

40

20 30 40 50 60 70

-7

SUCTION LINE TEMPERATURE (F)

-Ì 4 IÒ 16 2Ì
SUCTION LINE TEMPERATURE (C)

Fig. 39 — Cooling Charging Chart;

48HD,HH007

(F) (C)

105 41

95 35

85 29

75 24

OUTDOOR TEMP

(F) (C)

115 46

«620

90

<

551

a: 80

483

70-

276

207

60

50

40

30

20

30 4 0 50 60 70 80

-7

SUCTION LINE TEMPERATURE (F)

-Ì 4 IÓ 16 21 27
SUCTION LINE TEMPERATURE (C)

uj 414

2
Z

O

p345

o

3

«

80

27

105 41

95 35

85 29

75 24

65 18

Fig. 41 — Cooling Charging Chart;

48HDD.LDD.HHD,LHD008

L

20

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

Main and Pilot Burners — At the beginning of

each heating season, inspect for deterioration or

blockage due to corrosion or other causes. Observe
the pilot and main burner flames and adjust, if
necessary, referring to automatic Pilot Adjustment
or Main Burners sections of instructions.

Flue Gas Passageways — Inspect flue collector

box and upper areas of heat exchanger cells by

removing burner compartment access panel; then
remove flue cover and inspect heat exchangers.

Using a wire brush, clean all surfaces as required.

Combustion Air Blower — Clean periodically to

assure proper airflow and heating efficiency. Inspect
blower wheel every fall and periodically during
heating season. For the first heating season, inspect

blower wheel bimonthly to determine proper clean
ing frequency.

To inspect blower wheel, remove draft hood and

screen. Shine a flashlight into opening to inspect
wheel. If eleaning is required, remove motor and
wheel as follows:

1. Remove burner access panel.

2. Remove the 6 screws that attach induced draft
motor mounting plate to blower housing
(Fig. 42). The mounting plate will drop down.

3. Remove the 4 wires attached to the motor and
remove assembly from unit.

4. To remove blower, remove setscrews.

5. To remove motor, remove blower, then remove
the nuts that hold motor to mounting plate.

NOTE; Do not lose spacers for induced draft
motor.

6. To reinstall, reverse the procedure outlined
above.

Limit Switch — Aceess panel is located on the heat

section side panel (Fig. 3 and 4).
004,005,006,007 UNITS AND 48HDD,LDD/HD,

LD008 UNITS — Limit switch is located in the
upper section of the heat exchangers. Bi-metal
sensor is facing the airstream. Remove bracket
holding limit switch and remove screw holding
switch.

48HHD,LHD/HH,LH008 UNITS ^ Limit switch
is located on partition between blower section and
heat section. Remove plate and screw holding
switch.

Pilot Light — If pilot does not light as described in

Start-Up, Heating: Be sure pilot orifice is not
obstructed, gas pressure is not less than 3in. wg;

and air has been bled from gas supply. Check for

spark ignitor malfunctions as follows:

1. Shut off unit power supply.

2. Check that spark gap is 1/8 to 3/16 inch.

3. Check that spark generator is securely grounded
to furnace vestibule plate.

4. Check that high-voltage lead is securely con

nected between generator and electrode body.

5. Restore power. Check that 24 volts is supplied to
primary side of generator.

6. Check unit label diagram for correct terminal
usage if any wires are removed.

Automatic Pilot Adjustment

1. Turn off unit power supply, set system selector
switch at HEAT, and adjust thermostat to call
for heat.

2. Remove burner compartment access panel.

3. Remove screw cap cover on the top of the main

gas valve to expose pilot adjusting screw.

4. With a small screwdriver, turn adjustment screw
until flame is approximately 1 to 1-1/2 in. high.

5. Replace screw cap cover on pilot gas valve.

6. Observe burner operation and adjust main gas
valve for correct burner operation as required.

See Fig. 43 for proper flame appearance.

7. Replace all panels.

Automatic Gas Valve Sequence of Operation

— Thermostat calls for heat, energizing the spark
ignitor and simultaneously opening the pickup and
hold solenoids of the pilot gas valve (inside main gas
valve). The pilot gas ignites within 2 seconds, stop

ping the ignitor. Within 11 seconds, the pilot contact
(normally closed) opens, drops out the pickup sole
noid. Within 35 seconds, the pilot contact (normally

MAIN

BURNER
SECTION

Fig. 42 — Burner Section Details

MAIN
GAS
VALVE

Fig. 43 — Proper Flame Appearance

21

open) closes, energizing the heat motor in the main
gas valve. The main gas valve will open within
45 seconds.

Main Burners are factory set and should require

no adjustment. However, if burner adjustment is
necessary:

1. Perform Automatic Pilot Adjustment.

2. Turn gas valve to ON. Allow unit to operate at
least 15 minutes with furnace access panel in
place.

3. Remove access panel.

4. Loosen primary air shutter and adjust to a mini
mum opening of 5/8 inch.

5. Retighten primary air shutter and reinstall access
panel.

TO CHECK ignition of main burners and fan
switch operation, move thermostat dial above and
below room temperature several times pausing at
least one minute between cycles.

REMOVAL

1. Shut off manual main gas valve.

2. Shut off power to unit.

3. Remove evaporator air fan access panel, burner
compartment access panel and center post.

4. Disconnect gas piping at unit gas valve.

5. Remove (and mark) red wire from terminal no. 4
or W1 and brown wire from terminal no. 3 or C2
and violet wire from terminal W2 (connections
are dependent on whether a 2-stage or single­stage valve is on the unit).

6. Remove the 2 screws at rear of housing just
inside burner section.

7. Lift and slide assembly out.

REPLACEMENT

1. Slide assembly into burner section and push
snugly against vestibule plate.

2. Screw assembly down.

3. Connect red wire to terminal no. 4 or W1 and
brown wire to terminal no. 3 or C2 and violet
wire to terminal W2 (connections are dependent
on whether a 2-stage or single-stage valve is on
the unit).

4. Connect gas piping at unit gas valve.

5. Replace center post and access panels.

6. Turn on manual main gas valve.

7. Restore power to unit.

CLEANING

1. Remove burner assembly from unit as described
above.

2. Inspect burners and if dirty, remove by removing
retaining plate.

3. Using a soft brush clean burners as required.

4. Replace burners.

5. Replace burner assembly as described above.

Replacement Parts — A complete list of replace

ment parts may be obtained from any Carrier dis
tributor upon request.

22

m

TYPICAL WIRING DIAGRAM LEGEND

AHA

—
Assy
C
CAP.
CC
CH —
CLO —
CLS
COMP
CS —

DM —
DR —
EC —
ECT
Equip
Fu
Gnd
HPS
1
IDM
IDR
IFC
IFM
IFR
IPP Ignitor Power Pack
L
LPS
LS
MAT.
MGV
Mtr
NS
OAT.
OFM
PGV Pilot Gas Valve

Adjustable Heat Anticipator

—

Assembly

—

Contactor Compressor QT -

—

Capacitor RLC —

—

Cooling Compensator RS —
Crankcase Heater Std —
Compressor Lockout Sw —

__

Cooling Lockout Switch TB —

—

Compressor Motor TC —
Centrifugal Switch
Damper Motor
Damper Relay
Enthalpy Control

—

Economizer Thermostat
Equipment

—

Fuse

—

Ground
High-Pressure Switch

—

—

Ignitor Electrode

—

Induced Draft Motor

_

__

Induced Draft Relay

—

Indoor Fan Contactor
Indoor Fan Motor

—

—

Indoor Fan Relay

—

Light
Low-Pressure Switch
Limit Switch

—

Mixed Air Thermostat

__

Main Gas Valve
Motor
Night Setback Switch

—

Outdoor Air Thermostat

—

Outdoor Fan Motor

(48HD,LD008)

PI ­PS —

TDR —
TH ­TRAN -

o

o

□

•o

—•—

_

_________

—

——

Plug Assembly
Pilot Sensor
Ouadruple Terminal
Rotor Locking Circuit
Rollout Switch
Standard
Switch
Terminal Block
Thermostat, Cooling
Time-Delay Relay
Thermostat, Heating
Transformer

Marked Wire
Denotes Connection Point Between

Subbase and Thermostat

Terminal (Marked)

Terminal (Unmarked)
Terminal Block

Field Splice
Splice (Marked)
Factory Splice

Factory Wiring
Internal Connection

Accessory or Optional Wiring

Field Control Wiring
Field Power Wiring
To indicate common potential only,

not to represent wiring

TYPICAL WIRING DIAGRAM NOTES

(48HD,LD008)

1. Compressor and fan motors are thermally pro
tected — 3-phase motors are protected against
primary single-phasing conditions.

2. If any original wires must be replaced, use 90 C
wire or equivalent.

3. Numbers indicate the line location of used con
tacts. A bracket over (2) numbers signifies a
single pole double throw contact. An underlined

number signifies a normally closed contact. Plain
(no line) number .^signifies a normally open
contact.

4. Must use thermostat HH07AT172 or 174 with
subbase HH93AZ177.

5. Set heat anticipators at one amp (208/230-3-60).
Set heat anticipators at 1.2 amp (460-3-60).

6. Factory connected to 230-v or 460-v lead per unit
rated voltage. If 208-v power supply is used,
connect to 200-v lead and insulate 230-v lead.

23

ECONOMIZER ASSY.

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DM ^

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TWO POSITION DAMPER MOTOR ASSY.

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<±> <£>

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i®®'

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HPS .ECT

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o o

QT

BRN—

ORN/YEL

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PL I

o o

o

COMP

Typical Component Arrangement (48HO,LD008 Shown)

24

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o

£
w

00

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5

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
Tab la 6a

4

Form 48H,L-7S1 Supersedes 48HD-5SI: 48H,L-4SI

Printed in U S A

9-84 PC 111 Catalog No 534-805