Refrigerant System Component Service; Evaporator Coil; Replacing Unloader Valve Internal Parts; Unloader Valve Replacement - Carrier VECTOR 6500 Operation & Service Manual

c. Replacing Unloader Valve Internal Parts
1. Pump down the compressor. Refer to Section 8.6.2
step e.
2 Ensure the unit will not start automatically by dis-
abling any two way communication and placing the
Main Power switch in the OFF position. Disconnect
the high voltage source and lockout/tagout the re-
ceptacle.
3. Disconnect and remove coil.
WARNING
Do not unscrew unloader enclosing tube
nut all the way before breaking seal.
Entrapped pressure could result in injury.
4 Loosen the enclosing tube nut (see Figure 8−24) us-
ing installation/removal tool supplied with repair kit.
Ensure tube is loose and seal is broken then remove
tool, enclosing tube nut, enclosing tube, plunger with
plunger spring and o-ring
5. Check plunger for restriction due to: (a) corroded or
worn parts; (b) foreign material lodged in valve; (c)
bent or dented enclosing tube.
6. Install new parts. Do not over tighten enclosing tube
assembly. Torque to a 100 inch pounds (11.3 Nm).
7. Remove tool and install coil, refer to preceding step b.
8 Leak check and evacuate the compressor. Refer to
Sections 8.6.3 and 8.6.4.
9. Check operation, refer to preceding step a.
d. Unloader Valve Replacement
1. Pump down the compressor. Refer to Section 8.6.2.
2. Disconnect and remove coil.
WARNING
Do not unscrew unloader valve body
mounting bolts all the way before breaking
seal. Entrapped pressure could result in
injury.
3 Loosen the valve body mounting bolts. Tap the valve
body to break the seal and then remove bolts and
gasket.
4. Remove small screen from inside the compressor
head and ensure it is not obstructed. Clean or replace
as required.
5. Place new gasket onto replacement unloader valve
body (with flat side toward the head) and, using un-
62-11389
loader ring pliers (Carrier Transicold part number
07-00223-00) compress the unloader ring while in-
serting the unloader into the compressor head.
6. One valve body mounting hole is offset to assist in
correctly aligning the valve body and gasket. Insert
mounting bolts, align with gasket holes and mounting
holes in head. Start bolts by hand and then toque
mounting bolts 12 to16 ft-lbs (1.3 to 1.8 Nm).
7 Leak check and evacuate the compressor. Refer to
Sections 8.6.3 and 8.6.4.
8. Check operation, refer to preceding step a.
8.8 REFRIGERANT SYSTEM COMPONENT
SERVICE

8.8.1 Evaporator Coil

The use of recycled cardboard cartons is increasing
across the country. The recycled cardboard cartons
create much more fiber dust during transport than "new"
cartons. The fiber dust and particles are drawn into the
evaporator where they lodge between the coil fins. If the
coil is not cleaned on a regular basis, sometimes as
often as after each trip, the accumulation can be great
enough to restrict air flow, cause coil icing, repetitive
defrosts and loss of unit capacity. Due to the "washing"
action of normal defrost the fiber dust and particles may
not be visible on the face of the coil but may accumulate
deep within.
Clean the evaporator coil on a regular basis, not only to
remove cardboard dust, but to remove any grease or oil
film which sometimes coats the fins and prevents water
from draining into the drain pan.
Cardboard fiber particles after being wetted and dried
several times can be very hard to remove. Therefore,
several washings may be necessary.
a. Ensure the unit will not start automatically by dis-
abling any two way communication and placing the
Main Power switch in the OFF position. Disconnect
the high voltage source and lockout/tagout the re-
ceptacle.
b. Remove rubber check valves (Kazoo) from drain
lines of the evaporator to be cleaned.
c. Spray coil(s) with a mild detergent solution such as
Oakite 164 or 202) or any good commercial grade au-
tomatic dish washer detergent such as Electrosol or
Cascade and let the solution stand for a few minutes
and reverse flush (opposite normal air flow) with clean
water at mild pressure. A garden hose with spray
nozzle is usually sufficient. Make sure drain lines are
clean.
d. Re-install check valves and run unit until defrost
mode can be initiated to check for proper draining
from drain pan.
8−26