Carrier Gemini 38AU 16-28 Series Installation, Start-Up And Service Instructions Manual page 12

CKT
2
CKT
1
CKT
1
Fig. 8 — 38AUD Service Valve Locations
When a single piece evaporator coil with two separate circuits is
connected to a 38AUD, the lower coil circuit should be connected
to the 38AUD unit's Circuit 1 so that the evaporator's lower coil
segment is first-on/last-off (to avoid re-evaporation of condensate
on dry lower coil segments).
Plan the Circuit 1 and Circuit 2 tubing segments carefully, mark
each segment and check constantly as piping systems are assem-
bled to avoid piping errors.
The 38AUD unit cannot be field-piped as a single-circuit/tandem
system.
FINAL TUBING CHECK — 38AUD
Before completing the field piping connections to the 38AUD
unit service valves, confirm that the suction line to the indoor
coil's first-on/last-off circuit (and its companion liquid line) are
correctly identified as Circuit 1 use for the 38AUD unit. If a suc-
tion riser is required, it must be in Circuit 1.
Connecting 40RU to 38AUD
The 40RU fan coil in sizes 16, 25 and 28 is a face-split coil design
that also has its circuits designated as 1 and 2. See Table 10 and
Fig. 9. Note that the lower coil segment changes as the arrange-
ment of the 40RU changes. In a vertical arrangement, the 40RU
unit's lower coil segment is segment 2; this segment should be
connected to the 38AUD unit's Circuit 1. In a horizontal arrange-
ment, the 40RU unit's lower segment is now segment 1; this seg-
ment should be connected to the 38AUD unit's Circuit 1.
Note that refrigerant suction piping should be insulated.
Table 10 — 40RU Arrangement Details
40RU COOLING
ARRANGEMENT STAGE
Y1
Vertical
Y2
Y1
Horizontal
Y2
LIQUID LINE
MODEL SIZES
38AUD a 16-28
38AUZ 16-25
NOTE(S):
a. 38AUD units require TWO sets of parts.
CKT
2
Circuit 2
Connections
Circuit 1
Connections
40RU COIL CONNECT TO
SEGMENT 38AUD
2 Circuit 1
1 Circuit 2
1 Circuit 1
2 Circuit 2
Table 12 — Refrigerant Specialties Part Numbers
LIQUID LINE
SIZE (in.) SOLENOID VALVE (LLSV)
1/2 EF680035
5/8 EF680036
5/8 EF680036
Vertical Installation
Coil Segment 1
Coil Segment 2
First On/Last Off = 2
Horizontal Installation
Condensate Drain Connection
Fig. 9 — Typical Evaporator Coil Connections (40RU)
INSTALL FILTER DRIER(S) AND MOISTURE 
INDICATOR(S)
Every unit MUST have a filter drier in the liquid line. 38AUD
models require two filter driers (one in each liquid line). Locate
the filter drier(s) at the indoor unit, close to the evaporator coil's
thermal expansion valve (TXV) inlets.
The 38AU units include one (38AUZ) or two (38AUD) Puron-
duty filter drier(s), shipped in cartons attached to the unit basepan
(see Table 11). Remove the filter drier(s) and prepare to install in
the liquid line(s) at the evaporator coil. Do not remove connection
fitting plugs until ready to connect and braze the filter drier into
the liquid line position.
Installation of liquid line moisture indicating sight glass in each
circuit is recommended. Locate the sight glass(es) between the
outlet of the filter drier and the TXV inlet.
Refer to Table 12 for recommendations on refrigeration
specialties.
Table 11 — Puron-duty Filter Drier(s)
LIQUID LINE
MODEL SIZE QTY
38AUZ*16 1
38AUZ*25 1
38AUD*16 2
38AUD*25 2
38AUD*28 1
LLSV COIL SIGHT GLASS
EF680037
EF680037
EF680037
12
Liquid Line
Connection
Suction-Vapor
Connection
Condensate Drain
Connection
Coil Segment 2
Coil Segment 1
First On/Last Off = 1
DESICCANT
OD (in.) VOLUME
5/8 30 cu in.
5/8 30 cu in.
1/2 8 cu in.
1/2 16 cu in.
1/2 16 cu in.
FILTER
DRIER
KM680004
Provided with unit,
KM680005
see Table 11
KM680005
PART
NUMBER
REF.
KH43LS087
KH43LS087
KH43LS085
KH43LS085
KH43LS085