Carrier 38AUD 16 Series - Preliminary Charge; Step 6 - Install Accessories

17
Step 6 — Complete Refrigerant Piping Connections
IMPORTANT: Do not bury refrige rant piping
underground.
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 f actory 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 relief device.
Check 38AU Model with Evaporator Coil Connections —
Confirm before installation of unit that the evaporator coil
connec tions are consistent with this 38AU model. See
Table 3 on page 11.
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’ s two circuits are designated Circuit 1 and
Circuit 2. Circuit 1 is contro lled by the thermos tat’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 circuit is always the “lag” circuit.
See Fig . 8 for location of Circuit 1 and Circuit 2 service
valves and field piping connections. Circuit 1 is on the
left-han d side of the serv ice valve compar tment; Circuit 2 is
on the right.
When a sin g le piece evap or ator coil with two sep arate
circuits is connected to a 38AUD, the lower coil circuit
should be connected to the 38AUD’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).
Circuit 1
Connections
Circuit 2
Connections
CKT
1
CKT
1
CKT
2
CKT
2
C10355
Fig. 8 -- 38AUD Service Valve Loc ations
Plan the Circuit 1 and Circuit 2 tubing segments carefully,
mark each segment and check constantly as piping
systems are assembled to avoid piping errors.
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 suction 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 des ign that also has its
circuits desig nated as 1 and 2. See F ig . 9. Note that th e
lower coil segment changes as the arrangement of the 40RU
changes. In a vertical arrangement, the 40RU’ s lower coil
segment is segment 2; this segment should be connected to
the 38AUD’ s Circuit 1. In a horizontal arrangement, the
40RU’s lower segment is now segment 1; this segment
should be connected to the 38AUD’ s Circuit 1.
Note that refrigerant suction piping should be insulated.
40RU
Arrangement
Cooling
Stage
40RU Coil
Segment
Connect to
38AUD
Vertical
Y1
Y2
2
1
Circuit 1
Circuit 2
Horizontal
Y1
Y2
1
2
Circuit 1
Circuit 2
FIRST ON/LAST OFF = 2
VERTICAL INSTALLATION
FIRST ON/LA ST OF F = 1
HORIZONTAL INSTALLATION
1
2
2
1
C10071
Fig. 9 -- Typical Evaporator Coil Connections (40RU)
38AU