Carrier 69NT40-541-300, Операция и обслуживание, Страница: 102 / 152

6 − 14 T − 318
Copper Tube
(Apply heat for 10-15 seconds)
Bi-metallic Tube Connection
(Apply heat for 2-5 seconds)
Use of a wet cloth is not necessary due to rapid
heat dissipation of the bi-metallic connections
Braze Rod (’Sil-Phos” = 5.5% Silver, 6% Phosphorus)
Figure 6-20 Hermetic Thermostatic Expansion Valve Brazing Procedure
a. Removing the TXV:
1. Pump down the unit per paragraph 6.4.
2. If TXV replacement is to be performed from the front
of the unit, open the upper right (EFM#1) access
panel (see Figure 2-1) and remove the evaporator
fan motor.
3. Remove cushion clamp that secures the valve body
to the bracket.
4. Unbraze the equalizer connection (1/4”), the outlet
connection (5/8”), and then the inlet connection
(3/8”). See Figure 6-20. Be careful to protect the in-
sulation on the heaters and their wires.
5. Open the insulation flap. Flap is secured with Velcro
(Item 3, Figure 6-21).
6. Loosen the thumb screw and slide the bulb, out by
pulling it towards the front of the unit.
1
2
3
4
5
6
1. Hermetic Expansion Valve Bulb
2. Insulation
3. Insulation Flap
4. Velcro strip
5. Bulb Clamp
6. Thumb Screw
Figure 6-21 Hermetic Thermostatic Expansion
Valve Bulb Location
b. Installing the TXV
1. Braze inlet connection to inlet line (see Figure 6-20).
2. Braze outlet connection to outlet line.
3. Braze the equalizer connection to the equalizer line.
4. Reinstall the cushion clamp.
5. Thread the thermal bulb through the opening above
the evaporator coil (see Figure 2-2), and slide it un-
der the strap and secure the thumb screw. Close the
insulation flap. Reinstall bulb access panel.
6. Check superheat (refer to step 6.14.1).
6.15 EVAPORATOR COIL & HEATER ASSEMBLY
The evaporator section, including the coil, should be
cleaned regularly. The preferred cleaning fluid is fresh
water or steam. Another recommended cleaner is
Oakite 202 or similar, following manufacturer’s
instructions.
The two drain pan hoses are routed behind the
condenser fan motor and compressor. The drain pan
line(s) must be open to ensure adequate drainage.
6.15.1 Evaporator Coil Replacement
a. Pump unit down (refer to paragraph 6.4).
b. With power OFF and power plug removed, remove
the screws securing the panel covering the evapora-
tor section (upper panel).
c. Disconnect the defrost heater wiring.
d. Disconnect the defrost temperature sensor (see Fig-
ure Figure 2-2) from the coil.
e. Remove middle coil support.
f. Remove the mounting hardware from the coil.
g. Unsolder the two coil connections, one at the distribu-
tor and the other at the coil header.
h. After defective coil is removed from unit, remove
defrost heaters and install on replacement coil.
i. Install coil assembly by reversing above steps.
j. Leak check connections per paragraph 6.5. Evacuate
the unit per paragraph 6.6, and add refrigerant charge
per paragraph 6.7.