c. Determine which heater(s) need replacing by check- ing resistance on each heater. Refer to paragraph 2.3 for heater resistance values
d. Remove
e.Lift the bent end of the heater (with the opposite end down and away from coil). Move heater to the side enough to clear the heater end support and remove.
6.16ECONOMIZER, UNLOADER, LIQUID INJEC- TION AND OIL RETURN SOLENOID VALVE
a. Replacing the Coil
NOTE
The coil may be replaced without removing the refrigerant.
1Be sure electrical power is removed from the unit. Disconnect leads. Remove top screw and washer. Lift off coil. (See Figure
2Verify coil type, voltage and frequency of old and new coil. This information appears on the coil hous- ing.
b.Replacing Valve Internal Parts (Unloader Solenoid Only)
1Pump down the unit. Refer to paragraph 6.4.
2Be sure electrical power is removed from the unit. Disconnect leads. Remove top screw and washer. Lift off coil. (See Figure
3Remove the top screw (see Figure
4Loosen the enclosing tube locknut.
5Remove enclosing tube and locknut assembly. The gasket is inside the enclosing tube.
6Remove seat disc from inside of body and check for obstructions and foreign material.
7Place the seat disc into the valve body with the small- er diameter end facing up.
8Install stem and plunger.
9Place the enclosing tube locknut over the enclosing tube. Install spacer over enclosing tube making sure it is seated properly in the enclosing tube locknut. Tighten enclosing tube locknut to a torque value of 2.78 mkg (20
10Install coil assembly, washer and top screw.
11Evacuate and dehydrate the system. (Refer to section 6.6.) Charge unit with refrigerant per section 6.7.
12Start unit and check operation.
c.Replacing Valve
1 To replace the unloader, liquid injection or econo- mizer valve, pump down the unit. Refer to paragraph
6.4.To replace the oil return valve, remove the re- frigerant charge.
2Be sure electrical power is removed from the unit. Disconnect leads. Remove top screw and washer. Lift off coil. (See Figure
3Unbraze valve from unit and braze new valve in place
4Install coil. Evacuate low side and place unit back in operation. Check charge.
1
2
3
4
5
6
7
8
9
1. | Top Screw | 6. | Gasket |
2. | Washer | 7. | Stem and Plunger |
3. | Coil | 8. | Seat Disc |
4. | Locknut | 9. | Body |
5. | Enclosing Tube |
|
|
Figure 6-14. Unloader Solenoid Valve
1
2
3
4
1. | Slotted Screw | 4. Enclosing Tube and |
2. | Washer | Body |
3. | Coil |
|
Figure 6-15. Oil Return Solenoid Valve (ORV), Economizer Solenoid Valve (ESV), Liquid Injection Solenoid Valve (LIV)
6.17 EVAPORATOR FAN AND MOTOR ASSEMBLY
The evaporator fans circulate air throughout the container by pulling air in the top of the unit. The air is forced through the evaporator coil where it is either heated or cooled and then discharged out the bottom of