Carrier 28GH User Manual
Carrier
Instaliation instructions
Direct Expansion Evaporator Coil
GENERAL
These encased coils must be used in a hori
zontal position with the air flow in the direction as
indicated in Fig. 1.
Transportation Damage — If any damage is noted
when unpacking coil, file a claim with the trans
portation agency.
NIPPLE AUXILIARY
CONDENSATE CONN
28GH002,003
INSTALLATION
Install coil in the horizontal run of a supply air
duct from any furnace. Fig. 2 shows typical
installations. Attach ductwork to encased coil. Use
straps for hanging. Do not drill or screw into coil
condensate pan. Coil must be level for proper
condensate drainage.
If the duct cross-sectional area between coil and
furnace is smaller than entering air opening of
encased coil, a transition must be made in the duct.
The ratio of transition in the duct must not exceed
more than one inch for every seven in both the
horizontal and vertical planes.
Where it is necessary to reduce fan noise or
vibration, install a canvas connection in the duct
work on the entering air side of the coil.
When encased coil is installed in a crawl space,
attic or basement with less than 18 in. service
clearance above the unit, it is not possible to
service unit thru the access panel. In these cases,
part of the ductwork must be cut away or unit
must be removed from duct for servicing.
UNIT 28GH 002 003 i 004 i 005 006
DIM. (fi-in.)
CONN, (in, ODF)
Suction
Liquid
Condensate
Duct iniet (in.)
Duct Outlet (in.)
A
s I
C i
D j
V,
E i
F i
G ;
K i 14%
J i
K j __14%
i 2-G%l 2-4% 3-0%
1-3%
1 -4%
V
%
7/
/A
13%
22% i 26%
13% i
13%
18% i
22% i 26%
Fig. 1 — Dimensions
©Carrier Corporation 1969
1%
%
34%
34%
Fig. 2 — Typical Installation
Refrigerant Piping — Connection sizes are given in
Fig. I.
COILS 002 THRU 005 use Carrier Compatible
Fittings and accessory tubing package for connec
tions. Detailed instructions are included with the
tubing package. Do not remove rubber plugs from
Carrier Compatible Fittings on the coil until ready
to connect the suction or liquid line into the
fitting. If coil piping is left open, vapor holding
charge will escape and allow moisture to enter.
Form 28GH-1SI
COIL 006 must have the liquid and suction lines
soldered to the unit.
Refrigerant Control is a factory-installed thermal
expansion valve. For proper operation, locate the
feeler bulb outside the encased coil about 45
degrees above the horizontal center line of the
suction line.
Do not mount bulb such that capillary tube
extends from bottom of bulb. Clean suction line
for good contact with bulb. Secure bulb tightly to
suction Une with metal straps provided. If this is
not done, liquid may slug to the compressor.
Suction Line Insulation — Insulate entire suction
line. Tubing package has an insulated suction line.
Insulate suction line from encased coil to, and
surrounding, expansion valve feeler bulb on 28GH
Coils.
Refrigerant Charge — Coils 002 thru 005 have
vapor holding charge. Do not evacuate if accessory
tubing package with Carrier Compatible Fittings is
used. If sweat connections are used, purge or
evacuate coil and piping.
Coil 006 is shipped without charge. Purge or
evacuate coil and piping.
Refer to Standard Service Techniques Manual,
Chapter 1, pages 1-8 thru 1-14, and condensing
unit and/or tubing package instructions for details.
Condensate Drain
1. Connect the rubber elbow (furnished with unit)
to the primary drain. See Fig. 1.
2. Connect 7/8-in. copper tube to the elbow.
3. Form a trap in the 7/8-in. copper tube and run
the tubing to an open drain. Drain tube should
be pitched at least 1 in. per 10 ft.
4. Run individual condensate lines to the primary
and secondary drain pans. The condensate line
should discharge at a point where it can be
readily observed if a correction is needed.
HOW TO APPLY HOSE CLAMPS
1. Pull ends apart (Fig. 3).
2. Wrap around hose with toothed end beneath.
Prelatch by compressing until last ratchet teeth
catch behind small tabs.
LOCKiNG
CLAMP IN LOCKING POSiTiON
Fig. 3 — Hose Clamp
3. Grip adjacent bridges with pliers and compress
to tight position. Pliers can be held parallel to
hose where space is limited.
4. To remove, lift the locking tongue with
screwdriver.
Protective Plastic Film — Peel from unit panels
when installation is complete.
AIR QUANTITY
To prevent moisture blowoff do not exceed
cfm shown in Table 1.
Table 1 — Maximum Allowable CFM for 28GH Coil
COIL 28GH 002
Horizontal 975
003 004 005
1200 1580 1920
006
2560
Manufacturer reserves the right to change any product specifications without notice.
CARRIER AIR CONDITIONING COMPANY • SYRACUSE, NEW YORK
Tab 7
Form28GH-1SI New
Printed in U.S.A.
6-69
Codes D and MS
Catalog No. 532-841
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