Distributor Nozzle Change-Out; Filter Drier; Txv (Thermostatic Expansion Valve); Txv Location - Carrier AERO 39MN Installation, Start-Up And Service Instructions Manual

Distributor Nozzle Change-Out —
zles are factory supplied. Thermostatic expansion valves
(TXVs) are either field or factory supplied. Be sure that cor-
rect nozzle is installed in each distributor before installing ex-
pansion valve. See Table 5 for factory-installed distributor
nozzle sizes. Use AHUBuilder
for best performance; replacement nozzles must be field-in-
stalled. The correct nozzle is typically factory-installed.
CAUTION
Do not overheat distributor or cap. Failure to comply could
result in equipment damage.
Perform nozzle change-out procedure as follows:
1. Remove plastic end cap by using an electric heat gun or
a torch (see Fig. 70).
2. Clean off any grime.
3. Remove nozzle retaining ring with screwdriver or nee-
dle nosed pliers.
4. Remove nozzle from distributor by inserting 2 no. 6-32
threaded rods (at least 4-in. long) into the threaded holes
provided in the nozzle. See Fig. 71.
5. Insert correct nozzle into distributor body.
6. Re-insert nozzle retainer ring into distributor.
PLASTIC CAP
WITH VALVE
a39-4174
Fig. 70 — Distributor and Cap
NOZZLE
RETAINER
RING
SIMPLIFIED NOZZLE
REMOVAL
G
5
NO. 6-32 THREADED
PULLER HOLES
Fig. 71 — Nozzle Change-Out
A filter drier should be installed before the
Filter Drier —
TXV to ensure satisfactory valve operation.
Distributor noz-
® program to select nozzles
BODY TUBING
a39-2041
THREADED
PULLER RODS

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 dis-
tributor is mounted directly to the valve outlet. If the distribu-
tor cannot be mounted directly to the valve outlet, the dis-
tance between the valve outlet and distributor should not ex-
ceed 24 in. or refrigerant distribution problems may occur.
Also, the tube connecting the valve outlet and distributor can
be sized smaller to maintain refrigerant velocity and better
distribution. Elbows located between the expansion valve and
distributor will hinder proper distribution and are, therefore,
not recommended.
IMPORTANT: There are no liquid line penetrations
through the casings from the factory. Best distribution is
usually obtained if the expansion valve feeds vertically
up or down into the distributor. Assemble the refrigerant
piping and specialties inside the cabinet to determine the
hole location prior to using a hole saw to penetrate the
cabinet.
While not always convenient or possible, valve Types BI,
F, FB, and O are easier to service if mounted in a vertical and
upright position. If mounted in a horizontal position, the in-
ternal parts must be carefully reassembled to prevent damage.
Some consideration should also be taken in mounting larger
sized expansion valves. They must be adequately supported
since system vibration and the weight of the valve can cause
valve connections to fracture.
SOLDER TECHNIQUES — It is not necessary to disassem-
ble solder type valves when soldering to the connecting lines.
Any of the commonly used types of solders, e.g., 95-5, Sil-
Fos, Easy-Flo, Phos-Copper, Stay Brite 8 or equivalents, may
be used for copper-to-copper connections. When soldering a
brass refrigerant distributor to the valve, appropriate solders
for these connections, such as 95-5, Easy-Flo, Stay Brite 8 or
equivalents must be used. Regardless of the solder used, it is
important to direct the flame away from the valve body and
avoid excessive heat on the diaphragm. See Fig. 72 for de-
tails. As an extra precaution, a wet cloth should be wrapped
around the body and element during the soldering operation.
NOTE: This precaution will prevent overheating the valve
body which could damage the superheat spring and result in
flood-back problems. In addition, the Type O, EBF/SBF, and
EBS valve contain synthetic parts which can be damaged due
to overheating, resulting in poor valve performance.
a39-3970
Fig. 72 — Solder Technique
84