7.15 Evaporator Coil And Heater Assembly; Evaporator Coil Replacement; Figure 7.21 Hermetic Thermostatic Expansion Valve Brazing Procedure - Carrier 69NT40-541-001 Operation And Service

Figure 7.21 Hermetic Thermostatic Expansion Valve Brazing Procedure

Copper Tube
(Apply heat for 10-15 seconds)
Bi-metallic Tube Connection
(Apply heat for 2-5 seconds)
1. Pump down the unit per
2. Remove cushion clamps located on the inlet and outlet lines.
3. Unbraze the equalizer connection (1/4"), the outlet connection (5/8") and then the inlet connection (3/8").
See Figure 7.21. Be careful to protect the insulation on the heaters and their wires.
4. Remove insulation (Presstite) from expansion valve bulb.
5. Unstrap the bulb, located below the center of the suction line (4 o'clock position), and remove the valve.
b. Installing the Expansion Valve
1. Clean the suction line with sandpaper before installing bulb to ensure proper heat transfer. Apply thermal
grease to the indentation in the suction line.
2. Strap the thermal bulb to the suction line, making sure bulb is placed firmly into the suction line. See
7.21 for bulb placement.
3. Insulate the thermal bulb.
4. Braze inlet connection to inlet line, see
5. Braze outlet connection to outlet line.
6. Reinstall the cushion clamps on inlet and outlet lines.
7. Braze the equalizer connection to the equalizer line.
8. Check superheat (refer to
9. Check superheat. (Refer to
- 18°C (0°F).

7.15 EVAPORATOR COIL AND HEATER ASSEMBLY

The evaporator section, including the coil, should be cleaned regularly. The preferred cleaning fluid is freshwater 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.
7.15.1

Evaporator Coil Replacement

a. Pump unit down. (Refer to
b. With power OFF and power plug removed, remove the screws securing the panel covering the evaporator
section (upper panel).
c. Disconnect the defrost heater wiring.
d. Disconnect the defrost temperature sensor (see
Braze Rod ('Sil-Phos" = 5.5% Silver, 6% Phosphorus)
Section 7.4.
Figure 7.21.
Section 7.14.1).
Section 7.14.2 step Section
Section 7.4)
Figure
7–23
Use of a wet cloth is not necessary due to rapid
heat dissipation of the bi-metallic connections
7.14.1) Container box temperature should be at
3.2) from the coil.
Figure
T-316