Step 6 - Complete Refrigerant Piping; Connections - Carrier Gemini 38AU 07 Series Installation, Start-Up And Service Instructions Manual

A
S
FROM
EVAPORATOR
LEGEND
A - Suction Riser Without Trap
B - Suction Riser With Trap
S - Suction Line to Condensing Unit
Fig. 6 — Suction Line Piping - Double Riser
Outdoor Unit BELOW Evaporator Coil and No Vertical Riser
Segments
Select Circuit 1 suction line size from NO VAPOR RISER line.
Circuit 2 Suction Line
Because there is no hot gas bypass system in Circuit 2, no special
riser selections are necessary. Select Circuit 2 suction line from
bottom line for all 38AUDC installations.
Vertical Separation (outdoor unit above indoor unit)
Vertical elevation difference of 200 ft (60 m) is permitted when
the outdoor unit (38AUZ or 38AUD) is located above the indoor
unit.
Step 6 — Complete Refrigerant Piping

Connections

IMPORTANT: DO NOT BURY REFRIGERANT LINES.
IMPORTANT: A refrigerant receiver is not provided with the
unit. Do not install a receiver.
PROVIDE SAFETY RELIEF
If local codes dictate an additional safety relief device, purchase
locally and install locally. Installation will require the recovery
of the factory shipping charge before the factory tubing can be
cut and the supplemental relief device is installed.
Model 38AUD has two separate refrigeration systems. If required,
each circuit will require a field-supplied/installed supplemental re-
lief device.
CHECK 38AU MODEL WITH EVAPORATOR COIL
CONNECTIONS
Confirm before installation of unit that the evaporator coil con-
nections are consistent with this 38AU model. See Table 3 on
page 3.
INSULATE SUCTION LINES
Apply closed-cell tubular insulation to all suction lines between
evaporator coil connection and 38AU unit's suction service valve.
38AUD PIPING CONNECTIONS
The 38AUD unit's two circuits are designated Circuit 1 and
Circuit 2. Circuit 1 is controlled by the thermostat's Y1 (or TC1)
contact and will be the first circuit on and last circuit off. Circuit 2
is controlled by the thermostat's Y2 (or TC2) contact and this cir-
cuit is always the "lag" circuit.
See Fig. 7 for location of Circuit 1 and Circuit 2 service valves and
field piping connections. Circuit 1 is on the right-hand side of the
service valve compartment; Circuit 2 is on the left.
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
S
segment is first-on/last-off (to avoid re-evaporation of condensate
on dry lower coil segments).
B
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 12, 14 and 16 is a face-split coil design
that also has its circuits designated as 1 and 2. See Fig. 8. Note that
the lower coil segment changes as the arrangement of the 40RU
changes. In a vertical arrangement, the 40RU unit's lower coil seg-
ment is segment 2; this segment should be connected to the
38AUD unit's Circuit 1. In a horizontal arrangement, the 40RU
unit's lower segment is now segment 1; this segment should be
connected to the 38AUD unit's Circuit 1.
Note that refrigerant suction piping should be insulated.
40RU
ARRANGEMENT
Vertical
Horizontal
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.
11
CKT
2
CKT
1
Fig. 7 — 38AUD Service Valve Locations
COOLING 40RU COIL
STAGE SEGMENT
Y1
Y2
Y1
Y2
CIRCUIT 1
CONNECTIONS
CIRCUIT 2
CONNECTIONS
CONNECT TO
38AUD
2 Circuit 1
1 Circuit 2
1 Circuit 1
2 Circuit 2