131
Distributor Nozzle Change-Out
Distributor nozzles are factory supplied. Thermostatic expansion
valves (TXVs) are either field or factory supplied. Be sure that
correct nozzle is installed in each distributor before installing
expansion valve. See Table 11 for factory-installed distributor
nozzle sizes. Use
AHU
Builder
®
program to select nozzles for
best performance; replacement nozzles must be field-installed.
The correct nozzle is typically factory-installed.
Perform nozzle change-out procedure as follows:
1. Remove plastic end cap by using an electric heat gun or a
torch (see Fig. 105).
2. Clean off any grime.
3. Remove nozzle retaining ring with screwdriver or needle
nosed pliers.
4. Remove nozzle from distributor by inserting 2 no. 6-32
threaded rods (at least 4 in. long) into the threaded holes pro
-
vided in the nozzle. See Fig. 106.
5. Insert correct nozzle into distributor body.
6. Re-insert nozzle retainer ring into distributor.
Filter Drier
A filter drier should be installed before the TXV to ensure satis
-
factory valve operation.
TXV (Thermostatic Expansion Valve)
TXV LOCATION
Thermostatic expansion valves may be mounted in any position,
but they should be installed as close to the evaporator as possible.
If a refrigerant distributor is used with the TXV, best performance
is obtained if the distributor is mounted directly to the valve outlet.
If the distributor cannot be mounted directly to the valve outlet,
UPPER
SPLIT
LOWER
SPLIT
AIRFLOW
AIRFLOW
15
DIAMS
MIN
10
DIAMS
FIRST-ON, LAST-OFF
8 DIAMS
MIN
TXV
SENSING
BULB
TXV
SENSING
BULB
15 DIAMS
MIN
10
DIAMS
8
DIAMS
MIN
EVAPORATOR
COIL
COIL
CASING
UNIT
CASING
SIGHT
GLASS
FILTER
DRIER
SOLENOID
VALVE
DISTRIBUTOR
(TYP)
TXV
INSIDE
CASING
(TYP)
SOLENOID
VALVE
SIGHT
GLASS
FILTER
DRIER
LEGEND
TXV —
Thermostatic Expansion Valve
Fig. 103 —
Face Split Coil Suction-Line Piping
15
DIAMS
MIN
15
DIAMS
MIN
10 DIAMS
10 DIAMS
AIRFLOW
TXV SENSING
BULBS
8
DIAMS
MIN
8
DIAMS
MIN
FIRST-ON, LAST-OFF
EVAPORATOR COIL
DISTRIBUTOR
(TYP)
TXV
INSIDE
CASING
(TYP)
SIGHT
GLASS
SOLENOID
VALVE
FILTER
DRIER
FILTER
DRIER
SIGHT
GLASS
SOLENOID
VALVE
COIL
CASING
UNIT
CASING
LEGEND
TXV —
Thermostatic Expansion Valve
Fig. 104 —
Row Split Coil Suction-Line Piping
a39-2367
CAUTION
Do not overheat distributor or cap. Failure to comply could
result in equipment damage.
PLASTIC CAP
WITH VALVE
Fig. 105 —
Distributor and Cap
a39-4174
RETAINER
RING
NOZZLE
BODY
TUBING
S
IMPLIFIED NOZZLE
REMOVAL
G
5
NO. 6-
3
2 THREADED
PULLER HOLE
S
THREADED
PULLER ROD
S
Fig. 106 —
Nozzle Change-Out
a39-2041