Carrier 38HQ - Manual (Page 6)

REPLACE THE ACCURATER™ REFRIG­
ERANT CONTROL PISTON IN THE INDOOR
AND OUTDOOR COIL AS REQUIRED before
connecting refrigerant lines. See Table 3 and the
notes under the table for the pistons used in the
different system combinations. For piston replace­
ment
instructions, see AccuRater Servicing on
page 16.
CONNECT REFRIGERANT LINES to fittings on
indoor and outdoor sections, Fig. 1,2 and 6. Indoor
compressor section has 2 Compatible Fitting vapor
line connections. Outdoor coils and indoor fan coils
have Compatible Fitting vapor line connection and
liquid line flare connection.
Connect vapor line from outdoor coil to indoor
compressor section, and from compressor section
to indoor fan coil. Section vapor line as required
(Fig. 6). Use correct compressor section vapor line
connection to indoor fan coil and outdoor coil.
Unit Compatible Fitting(s) permits mechanical or
sweat connection as described below.
When using 1-1/8 in. field-supplied vapor line
(38HQ146 Systems^ remove vapor line adapters (4)
shipped in compressor section. Sweat connect 1-1/8
in. end of adapter to each end of vapor lines. Con­
nect 3/4-in. end of adapters to vapor line Com­
patible Fitting(s) on outdoor coil, indoor
compressor section and indoor fan coil.
When a 7/8-in. field-supplied vapor line is used
on 38HQ140, 4 field-supplied 3/4-in. to 7/8-in.
vapor line adapters must be provided (not required
if 7/8-in. 38CQ accessory tubing is used).
Flare and connect liquid line from outdoor
coil to indoor fan coil. (Do not disassemble
AccuRater.) It is not necessary to flare system
liquid line if an accessory flare-to-Compatible
Fitting Coupler is used for liquid line connec­
tion. See Accessory Coupler, Fig. 7.
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 O-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.
Fig. 6 — Refrigerant Piping Connections