Carrier III 38HQ User Manual
Number One
AirConditbning
l\Mer
Division of
Carrier Corporation
Carrier Parkway • Syracus
N Y 13221
Weathermaster III Dual-Compressor
Heat Pump
(Outdoor Coil Section; Indoor Compressor Section)
INDEX
Page
SAFETY CONSIDERATIONS
.............................
INSTALLATION.....................................................3
Step 1 — Check Equipment and Jobsite . 3
• UNPACKAGE UNITS
• INSPECT EQUIPMENT
• COMPLETE OR CONSIDER SYSTEM
REQUIREMENTS
Step 2 — Install Outdoor Coil
Section.................................................4
• ON THE GROUND
• ON THE ROOF
Step 3 — Install Indoor Compressor
Section.................................................5
Step 4 — Install Indoor Fan-Coil and
Electric Heater
Step 5 — Make Piping Connections
....................................
................
• REPLACE THE ACCURATER™
REFRIGERANT CONTROL PISTON(S)
• CONNECT REFRIGERANT LINES
Step 6 — Install Fan Control Package ... 6
Page
I
Step 7 — Install Outdoor Ambient
Switch...................................................6
Step 8 — Install Room Thermostat,
Outdoor Thermostat(s) and
Emergency Heat Relay
Step 9 — Make Electrical Connections... 8
.......................
8
• INSTALL A BRANCH CIRCUIT
DISCONNECT PER N.E.C.
• ROUTE LINE POWER LEADS INTO
COMPRESSOR SECTION
• CONNECT GROUND LEADS AND
POWER WIRES
• CONNECT POWER LEADS FROM
INDOOR COMPRESSOR SECTION
TO OUTDOOR COIL SECTION
5
5
• CONNECTCONTROL WIRING
INITIAL START-UP................................................9
SEQUENCE OF OPERATION.............................. 9
SERVICE.................................................................. II
MAINTENANCE .................................................... 15
SAFETY CONSIDERATIONS
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 mainten
ance functions of cleaning coils and filters and re
placing filters. All other operations should be per
formed by trained service personnel. When working
on air conditioning equipment, observe precautions
in the literature, tags and labels attached to the unit
© Carrier Corporation 1979
and other safety precautions that may apply.
Follow all safety codes. Wear safety glasses and
work gloves. Use quenching cloth for brazing opera
tions. Have fire extinguisher available for all brazing
operations.
Form 38HQ-6SI
4 -0" OVERHEAD SPACE REQUIRED
FOR SERVICE AND AIRFLOW
VAPOR LINE CONN (ON SERVICE VALVE)
i-b*'-
liquid line
CONN. (ON
SERVICE VALVE)
5" ll“
15’ Is
MTG SLOTS
(USE ANY 2)
^ SPACE REQUIRED FOR SERVICE ^AIRFLOW
Certified dimension drawings available on request
38 HQ
OUTDOOR
COIL
SECTION
i DIAM HOLE
FOR CONTROL
WIRING
DRAINAGE HOLES
I i' DIAM
HOLE FOR
POWER
WIRING
k DIAM HOLE
VAPOR LINE CONN TO
OUTDOOR COIL
VAPOR LINE CONN.
TO INDOOR COIL ‘
38HQ
INDOOR
COMPRESSOR
SECTION
SPACE REQUIRED FOR SERVICE
FOR COMPRESSOR
SECTION LINE POWER
WIRING
Certified dimension drawings available on request
Fig. 2 — Dimensions and Connections, 38HQ
Indoor Compressor Section (Table 2)
DIAM HOLE
FOR OUTDOOR
COIL SECTION
LINE POWER WIRING
(SEE ELECTRICAL
DATA AND WIRING)
DIAM HOLE FOR
CONTROL WIRING
Fig. 1 — Dimensions and Connections, 38HQ
Outdoor Coil Section (Table 2)
Table 1 — Carrier-Approved 38HQ
Weathermaster III Dual-Compressor
Heat Pump Systems
INDOOR
COMPRESSOR
SECTION
38HQ227
38HQ234
OUTDOOR
COIL
SECTION
38HQ940
38HQ960
INDOOR
FAN/COIL
40FS160/28VQ036
40FS200/28VQ042
Table 2 — Physical Data
INDOOR COMPR SECTION
Operating Wt (lbs)
38HQ227
205
Dimensions (ft-in.)
Width
A
Depth B
Height
C
1-11-1/8 (add 3/4-in for
Refrigerant Fittings
Compressor
no. 1
MD2713GM
(46)
(Oil Recharge, oz) no. 2
MD3413GM
(46)
AccuRater Size (in.)
Indoor no 6 ( 0670) no 7(0760)
Outdoor no 3 (.0550)*
Refrig Conn (in.)
OUTDOOR COIL SECTION
Operating Wt (lb)
3/4 3/4
38HQ940 38HQ960
107
Dimensions (ft-in.)
Diameter
Unit Height B
Coil Height
A
C
2-5-1/4
2- 8 3- 8
1-11 2-11
Refrig Conn
Vapor (in., ODF)
Liquid (in., ODF)
3/4, Compatible Fitting
3/8, Flare Fitting
*Piston size shown is shipped with section Remove factory-
installed piston: replace with size shown per text
38HQ234
2-2-3/32
1-4-3/16
MD3413GM
MD3413GM
no 5 ( 0635)
2-5-1/4
225
(46)
(46)
125
©
Table 3 — Heater Airflow Data
COMPRESSOR
PART NO.
38CQ900102
38CQ900122
38CQ900132
38CQ900152
38CQ900172
38HQ900011
38HQ900002
38RQ900012
38CQ900072
38RQ900072
TUBING
PACKAGE
38GC900071 10
38GC900081 18
38GC900091
38GC900101 35
38GC900111 50
_ ___ TUBING
INDOOR
SECTION
38HQ227
38HQ234
HEATER MINIMUM ALLOWABLE
SIZE
8 thru 20 kw
(40FQ91 6010 thru 090)
10 thru 25 kw
(40FQ920060 thru 1 50)
Airflow (cfm)
1150
1550
Fan Speed
Low
Low
Table 4 — Accessories
DESCRIPTION
Six 38CQ900081 Low-voltage Honeywell Thermostat (HH07AT071) and Thermostat Subbase (HH93AZ073)
with automatic changeover
Six 38CQ900111 Low-voltage Honeywell Thermostat (HH07AT071) and Thermostat Subbase (HH93AZ075)
with manual changeover
Six 38CQ900091 Liquid Line Filter-Drier
Six 38CQ900141 Solid State Time Guard (24 v)
SixHH22AG110 Optimizer Control
Hot Shot Heat Reclaim Device
Six 38HQ900001 Outdoor Thermostat
Six 38RQ900001 Emergency Heat Relay
Six 38C0900061 two-packs. Flare (3/8-in ) to compatible (3/8-in ) couplings
Six 38RQ900061 Heat Pump Stand for Outdoor Coil Section
Suction*
Tube End
Evap
3/4
3/4
O D. (in )
Cond
3/4
3/4
3/4
3/4
COMPR
SECTION
38HQ227
38HQ234
Length
(ft)
25
Liquid
O.D
(in.)
3/8
3/8
3/8
3/8
3/8 3/8
1-1/8 in OD Suction Tube, Field Supplied
Tube End
OD (in )
3/8
3/8
3/8
3/8
0 D.
(in.)
3/4 3/4 3/4
3/4 3/4
3/4 3/4
3/4
3/4
‘Suction line is insulated and has a 90° bend at one end
INSTALLATION
Step 1 — Check Equipment and Jobsite
UNPACKAGE UNITS — Move units to final loca
tion. Slide units from cartons taking special care
not to damage service valves, compatible fittings
or grilles. Check unit model numbers. Use only
Carrier-approved unit combinations in system. See
Table 1.
INSPECT EQUIPMENT — File claim with ship
ping company if shipment is damaged or incomplete.
COMPLETE OR CONSIDER SYSTEM RE
QUIREMENTS before installing the 38HQ units.
Consult local building codes and National Elec
trical Code (NEC) for special installation
requirements.
When installing units, allow sufficient space for
airflow clearance (outdoor unit), wiring, refrigerant
piping and servicing unit. Position outdoor unit so
water or ice from roof cannot drop directly on top
of unit. Maximum allowable vertical distance be
tween indoor and outdoor sections is 50 feet. It is
strongly recommended that 38HQ units be used
with only Carrier-approved indoor sections (see
Table 1).
Outdoor Coil Section — Make provision for con
densate drainage and defrost water disposal whether
unit is installed on ground, roof or off-the-wall
platform. Outdoor unit must be elevated 12 in. to
18 in. in areas of heavy snowfall. (Ensure unit base-
pan drainage holes are not blocked. See Fig. 1.) See
Step 2, Install Outdoor Coil Section for details.
Roof installation method for 38HQ depends on
building construction and special requirements of
local codes. Make sure roof can support unit weight.
Indoor Compressor Section — Locate unit in base
ment, garage or utility room. Indoor locations with
in the living space are not recommended. Basement
installations also require careful planning to avoid
areas directly under bedrooms, living rooms, etc.
Insert felt isolation pad (factory supplied) be
tween unit and a level rigid mounting base to absorb
vibration. Isolate interconnecting tubing from
framing and ductwork or where tubing runs thru
stud spaces, enclosed ceilings or pipe chases. Use
isolation type hanger, Fig. 3, since rigid fastening
will transmit pulsation to structure creating ob
jectionable sound.
. -.-.A ■ ■
System Refrigerant Control consists of factoryinstalled bypass-type AccuRater™ devices located
as shown in Fig. 15. These metering devices include a
replaceable orifice piston that is calibrated to
regulate refrigerant flow. Piston data is given in
Table 2. In some instances, the factory-installed
piston must be replaced by a factory-supplied re
placement piston. Where required, substitute
pistons as described in Step 5 and as indicated on
tags attached to system AccuRater devices.
Step 2 — Install Outdoor Coil Section
ON THE GROUND — Use a solid, level concrete
pad as shown in Fig. 4. Position unit so that coil
drainage holes in basepan overhang the pad. (See
Fig. 1 for drainage hole locations.) Be sure pad does
not obstruct drainage holes (water drains from holes
during heating and defrost cycles). Attach unit to
pad with 1 / 4-in. mounting bolts. Any 2 holes in unit
basepan may be used to fasten unit to pad.
Construct round, 24-in. diameter 6-in. thick pad a
minimum of 6 in. above grade to provide clearance
under holes for drainage and ice build-up. In areas
where prolonged subfreezing temperatures or snows
occur: increase clearance by using accessory heat
pump stand to support unit 12 to 18 in. off concrete
base. See Fig. 4. Be sure stand does not obstruct coil
drainage holes. Avoid mounting unit in prevailing
winds to minimize effect on defrost performance.
Construct wind break if necessary. Extend a 12-in.
gravel apron around pad for condensate and defrost
water drainage field.
Provide support bracket from structure or other
solid support to outdoor unit to give stability. Since
it is lightweight, the outdoor section may be
Fig. 4 — Unit Support Details
mounted on a platform attached to or built out from
structure. Construct platform using drainage and
clearance recommendations above. Locate and con
struct platform to avoid possible transfer of unit
vibration to structure. See Table 2 for unit weight.
ON THE ROOF: Install a level platform or frame to
support unit. Elevate unit for proper clearance as
previously described for on-the-ground installation.
Plan roof design and water drainage to prevent unit
from sitting in water. Flash all roof openings to
prevent leaks.
Step 3 — Install Indoor Compressor Section on
a level, rigid, solid platform or concrete floor. Do
not install in a living area.
Insert 1/4-in. asphalt-impregnated felt pad
(supplied) between unit basepan and mounting
surface to provide full unit support and vibration
attenuation. (Do not use vibration isolators under
corners of basepan.)
Step 4 — Install Indoor Fan-Coil and Electric
Heater as described in Installation Instructions
supplied with this equipment. Install and connect
thermostats and other controls as described in the
steps that follow.
Step 5 — Make Piping Connections — The
38HQ sections may be connected to indoor fan-coil
using Carrier accessory tubing packages or fieldsupplied tubing of refrigerant grade. See Table 2 for
unit piping connection types, sizes and line size
recommendations and Table 4 for accessory tubing
sizes. Maximum allowable system liquid line length
is 100 feet. Maximum vapor line length from com
pressor section to indoor coil is 50 feet. Maximum
vapor line length from compressor section to out
door coil is 50 feet.
When other than 25 ft of interconnecting piping
is used, follow special requirements described in
Refrigerant Charging. Do not use less than 10 ft of
vapor or liquid line.
Do not use damaged or contaminated tubing.
Always evacuate or purge indoor coil, compressor
section and tubing system. When purging, use fieldsupplied refrigerant, not unit refrigerant.
When making tubing connections, be sure to
provide clearance at unit for electrical connections.
Follow tubing isolation recommendations described
previously.
REPLACE THE ACCURATER™ REFRIG
ERANT CONTROL PISTON(S) before connect
ing refrigerant lines as applicable. Refer to tags
attached to AccuRater device. Replacement pistons
are shipped with compressor section and are to be
installed as directed on tag. Replacement procedure,
briefly described below, is detailed on tag. Also, see
AccuRater Servicing for additional information.
When connecting indoor compressor section
38HQ227 to outdoor coil section 38HQ940, remove
no. 4 piston from outdoor coil AccuRater device;
replace with no. 3 piston. Attach AccuRater identi
fication sticker to unit (replacing existing sticker, if
any).
CONNECT REFRIGERANT LINES to fittings on
indoor and outdoor sections. Fig. 1, 2 and 5. Indoor
compressor section has 2 Compatible Fitting vapor
line connections. Outdoor and indoor fan-coil
sections have Compatible Fitting vapor line connec
tion and liquid line flare connection.
Flare and connect liquid line from outdoor coil
section to indoor fan-coil unit. It is not necessary
to flare system liquid line if an accessory flare-to-
Fig. 5 — Refrigerant Piping Connections
5
Compatible Fitting coupler is used for liquid line
connection. See accessory coupler, Fig. 6.
Connect vapor line from outdoor coil section to
indoor compressor section, and from compressor
section to indoor fan-coil. Section vapor line as
required (Fig. 5). Use correct compressor section
vapor line connection to indoor and outdoor coils.
Unit Compatible Fittings permit mechanical or
sweat connection as described below.
When a 1-1/8 in. field-supplied vapor line is used
on 38HQ234, four field-supplied 3/4-in. to 1-1 / 8 in.
vapor line adapters must be provided.
Insulate Refrigerant Lines — After making tubing
connections, the compressor section fittings must be
insulated. Butt the Armaflex tubing insulation (pro
vided in tubing package) against the Compatible
Fittings. Secure the insulation with Prestito or an
equivalent material which provides both adhesion
and insulation. Also wrap the Compatible Fittings
with Prestito to prevent sweating.
Mechanical Connection-to-Compatible Fitting
(Mate one set of connections at a time.)
1. Loosen nut on Compatible Fitting one turn. Do
not remove.
2. Remove plug and be sure 0-ring is in the groove
inside the Compatible Fitting.
3. Cut tubing to correct length.
4. Insert tube into Compatible Fitting until it
bottoms.
5. Tighten nut until it bottoms on back coupler
flange. Keep tube bottomed in Compatible
Fitting while tightening nut.
Sweat Connection-to-Compatible Fitting (Use
refrigerant grade tubing.)
1. Remove locking nut, rubber O-ring and Schrader
core from valve.
2. Cut tubing to correct length.
3. Insert tube into Compatible Fitting. Wrap top
and bottom of service valves in wet cloth to pre
vent damage by heat. Solder with low tempera
ture (430 F) silver alloy solder.
4. Replace Schrader core.
5. Evaeuate or purge system with field-supplied
refrigerant.
Accessory Flare-to-Compatible Fitting Coupler is
shown in Fig. 6. Attach flare nut on coupler to flare
fitting on unit liquid line connection. Connect liquid
line to Compatible Fitting using mechanical or
sweat connection. When mechanical connection is
made, use 2 wrenches to tighten Compatible Fitting
nut — one to hold coupler and one to tighten nut.
Fig. 6 — Accessory Coupler
Step 6 — Install Fan Control Package (factory
supplied; packaged separately inside indoor com
pressor section) — This control, consisting of a
transformer and a relay, provides high-speed fan
operation when both compressors are energized.
Refer to connection diagram in Fig. 7 for wiring
details. Install control as follows:
1. Remove factory-installed transformer from
indoor fan-coil unit electric heater package.
Refer to 40FS service instructions as required.
2. Install fan control package in upper right-hand
corner of the 40FS.
3. Route wires from controls to heater package thru
knockouts provided. Restore transformer wiring
connections including ground wire.
4. Connect black wire from indoor fan relay (IFR)
terminal no. 4 (or no. 6) to black wire from
indoor fan relay no. 2 (IFR-2) terminal no. 3.
(Cut off male connector from IFR wire; supply
wire nut to splice wires.)
5. Connect black wire from IFR-2 terminal no. 6 to
fan speed selector block terminal no. 1 (high
speed).
6. Connect blue wire from IFR-2 terminal no. 1 to
fan speed selector block terminal no. 3 (low
speed).
7. Connect low-voltage field control wires between
indoor compressor section and indoor fan relay
(IFR-2) orange pigtails (TB OA to OFR-2, ter
minal no. 4; contactor C-2, terminal C to IFR-2,
terminal no. 5). Field-supplied, 24-gage, NEC
Class 2 thermostat wire may be used.
Step 7 — Install Outdoor Ambient Switch
(OA) (factory-supplied; packaged separately inside
indoor compressor section) — This switch activates
compressor no. 2 when the first heating thermal
balance point is reached. The switch is installed in
the same manner as the outdoor thermostat (step 8),
except refer to Fig. 7 for correct wiring.
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