Carrier 38AUQ Installation, Start-Up And Service Instructions Manual page 9

LIQUID LINE
SIZE (in.)
3
/
8
1
/
2
5
/
8
†
38AUD units require TWO sets of parts.
INSTALL LIQUID LINE SOLENOID VALVE —
It is recommended that a bi-directional solenoid valve be
placed in the main liquid line (see Figs. 5 & 6) between the
outdoor unit and the indoor coil. Locate the solenoid valve at
the end of the liquid line, near the outdoor unit connections,
with flow direction arrow pointed at the outdoor unit. Refer to
Table 5. (A liquid line solenoid valve is required when the
liquid line length exceeds 75 ft [23 m].) This valve prevents
refrigerant migration (which causes oil dilution) to the
compressor during the off cycle, at low outdoor ambient
temperatures. Wire the solenoid according to the unit label
diagram.
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment
damage.
Failure to use a solenoid valve relay (SUR) accessory may
cause overload of Comfort Alert Diagnostic Module
(CADM) and compressor alarm lock out.
CAPACITY CONTROL LIQUID LINE SOLENOID VALVE
Evaporator capacity control via liquid solenoid valve is not rec-
ommended for use with 38AUQ models.
TXV
INDOOR SENSING
COIL CKT BULB
15 DIAMS
AIRFLOW
10
MIN
DIAMS
TXV — Thermostatic Expansion Valve
Fig.5 — Location of Sight Glass(es) and Filter Driers
(typical 38AUQ/40RUQ size 07 & 08 systems)
Table 5 — Refrigerant Specialties Part Numbers.
LIQUID LINE
SOLENOID VALVE (LLSV)
ALC-066208
†
ALC-066209
ALC-066212
EQUALIZER LINE
SIGHT GLASS
A LOCATION
FILTER DRIER
A LOCATION
TXV
8 DIAMS
MIN
LIQUID
LINE
SOLENOID
VALVE
LEGEND
LLSV SIGHT
COIL GLASS
AMG-24/50-60 HMI-1TT3
AMG-24/50-60 HMI-1TT4
AMG-24/50-60 HMI-1TT5
TXV
INDOOR SENSING
COIL CKT 2 BULB
15 DIAMS
AIRFLOW
10
MIN
DIAMS
TXV
SENSING
INDOOR
BULB
COIL CKT 1
15 DIAMS
AIRFLOW
10
MIN
DIAMS
TXV — Thermostatic Expansion Valve
Fig.6 — Location of Sight Glass(es) and Filter Driers
(typical 38AUQ/40RUQ size 12 system)
Table 6 — Minimum Outdoor Air Operating Temperature
%
UNIT COMPRESSOR
CAPACITY
38AUQ07
38AUQ08 100
38AUQ12
*Applies to Cooling mode of operation only.
†Wind baffles (field-supplied and field-installed) are recommended
for all units with low ambient head pressure control. Refer to Low
Ambient Control Installation Instructions (shipped with accessory)
for details.
Table 7 — Insulation for Vapor Line Exposed
to Outdoor Conditions
LENGTH OF EXPOSED
VAPOR LINE*
ft
10
25
35
50
*Recommended vapor line insulation for piping exposed to outdoor
conditions to prevent loss of heating during heating cycle. When
vapor line goes through interior spaces, insulation should be
selected to prevent condensation on cooling cycle. Heating capac-
ity should be reduced 1000 Btuh (295 W) if over 35 ft (11 m) of
3
vapor line with / in. (19 mm) insulation is exposed to outdoor con-
4
ditions.
†Closed cell foam insulation with a thermal conductivity of: 0.28 Btu
2
• in./ft • h • °F (0.04 W/m • °C).
9
FILTER
DRIER
Provided with unit
See Table 4
EQUALIZER LINE
SIGHT GLASS
LOCATION
TXV
CKT 2
8 DIAMS
MIN
TXV
CKT 1
8 DIAMS
MIN
LEGEND
MINIMUM OUTDOOR
TEMP — F (C)*
Head Pressure
Standard Unit
35 (1.7) –20 (–28.9)
35 (1.7) –20 (–28.9)
35 (1.7) –20 (–28.9)
INSULATION THICKNESS†
m in.
3
3 /
8
1
8 /
2
3
11 /
4
15 3 /
4
FILTER DRIER
LOCATION
LIQUID
LINE
SOLENOID
VALVE
Control†
mm
10
13
19
19