18
Install Filter Drier(s) and Moisture Indicator(s) —
Every unit MUST have a filter drier in the liquid line.
38A U D models requir e 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.
38AU units include one (38AUZ) or two (38AUD)
Puron-duty filter drier(s), shipped in cartons attached to
the unit basepan. Remove the filter drier(s) and prepare to
install in the l iquid line(s) at the evapora tor coil. Do not
remove connection fitting plugs until ready to connect and
braze the filter drier into the liquid line position.
Table 9 – Puron-duty Filter Drier(s)
Model-Size Qty
Liquid
Line OD
Desiccant
Volume
Part
Number Ref
38AUZ*16 1
5
/
8
-in 30 cu. in. KH43LS087
38AUZ*25 1
5
/
8
-in 30 cu. in. KH43LS087
38AUD*16 2
1
/
2
-in 16 cu. in. KH43LS085
38AUD*25 2
1
/
2
-in 16 cu. in. KH43LS085
Installation of liquid line moisture indi cating sightglass in
each circuit is recommended. Locate the sightglass(es)
between the outlet of the filter drier and the TXV inlet.
Refer to Table 10 for recommendations on re frigeration
specialties.
In some applications, depending on space and convenience
requir ements, it may be des irab le to install 2 filter driers and
sig ht glass es in a single circuit application. One filter drier
and sight glass may be installed at A locations (see Fig. 10)
or 2 filter driers and s igh t glasses may be installed at B
locations (see Figs. 10 and 1 1).
Select the filter drier for maximum unit capacity and
minimum pressure drop. Complete the refrige rant piping
from the indoor unit to the outdoor unit before opening
the liquid and suction lines at the outdoor unit.
Install Liquid Line Solenoid Valve —
It is recommended that a solenoid valve be placed in the
main liquid line (see Figs. 10 and 11) between the
condensing unit and t he evaporator coil. Locate the
solenoid valve at the outlet end of the liquid line, near the
evapora tor coil connecti ons, with flow direction arrow
pointed at the evaporator coil. Refer to Table 10. (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 in parallel with the compressor
contactor coil (see Figs. 10 and 11). This means of
electrical control is referred to as solenoid drop control.
INDOOR
COIL CKT 2
AIRFLOW
INDOOR
COIL CKT 1
AIRFLOW
15 DIAMS
MIN
10
DIAMS
8 DIAMS
MIN
TXV
SENSING
BULB
EQUALIZER LINE
SIGHT GLASS
A LOCATION
SIGHT
GLASSES
B LOCATION
TXV
CKT 2
FILTER DRIER
A LOCATION
FILTER
DRIERS
B LOCATION
FLOW
TXV
SENSING
BULB
TXV
CKT 1
8 DIAMS
MIN
15 DIAMS
MIN
10
DIAMS
Single Circuit Coil Piping Configuration
For single compressor condensing units
Dual Circuit Coil Piping Configuration
For single compressor condensing units
15 DIAMS
MIN
10
DIAMS
8 DIAMS
MIN
INDOOR
COIL CKT
AIRFLOW
TXV
SENSING
BULB
EQUALIZER LINE
SIGHT GLASS
A LOCATION
TXV
FILTER DRIER
A LOCATION
LIQUID LINE
SOLENOID
VALVE
FLOW
LIQUID LINE
SOLENOID
VALVE
C10202
Fig. 10 -- Location of Sight Glass(es) and Filter Driers
Typical 38AUZ Systems
AIRFLOW
SUCTION
CIRCUIT 2
SUCTION
CIRCUIT 1
AIRFLOW
15 DIAMS
MIN
10
DIAMS
8 DIAMS
MIN
TXV
SENSING
BULB
EQUALIZER LINE
SIGHT
GLASSES
TXV
CKT 2
FILTER
DRIERS
LIQUID LINE
SOLENOID VALVE
CIRCUIT 2
FLOW
LIQUID LINE
SOLENOID VALVE
CIRCUIT 1
FLOW
TXV
SENSING
BULB
TXV
CKT 1
8 DIAMS
MIN
15 DIAMS
MIN
10
DIAMS
Dual Circuit Coil Piping Configuration
For two circuit condensing units
C10072
Fig. 11 -- Location of Sight Glasses and Filter Driers
Typical 38AUD Systems
Table 10 – Refrigerant Specialties Part Numbers.
MODEL SIZES
LIQUID LINE
SIZE (in.)
LIQUID LINE
SOLENOID VALVE (LLSV)
LLSV
COIL
SIGHT
GLASS
FILTER
DRIER
38AUD 16---25
1
/
2
EF680035 EF680037 KM680004
provided with unit
see Table 9
5
/
8
EF680035 EF680037 KM680005
38AUZ 16---25
5
/
8
EF680028 EF680032 KM680005
38AUD units require TWO sets of parts.
38AU
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