Carrier 69NT40-521 manual To Replace the Evaporator Coil, To Replace the Evaporator Fan Assembly

f.Open cylinder valve. Slowly close bleed-off valve to increase pressure on switch. The switch should open at a static pressure up to 25 kg/cm@ (350 psig). If a light is used, light will go out. If an ohmmeter is used, the meter will indicate open circuits.

g.Slowly open bleed-off valve to decrease the pressure. The switch will close at 18 kg/cm@ (250 psig).

6.13EVAPORATOR COIL AND HEATER ASSEMBLY

The evaporator section, including the coil, should be cleaned regularly. The preferred cleaning fluid is fresh water or steam. Another possible cleaner is Oakite 202 or similar, following manufacturer’s instructions.

The two drain pan hoses connected to the drain pan are routed behind the condenser fan motor and compressor. The drain pan line(s) must be open to ensure adequate drainage.

To Replace the Evaporator Coil:

a.Pump unit down. (See Figure 2-5, refer to section 6.3.)

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 sensor from the coil. The defrost termination sensor (DTS) is located on the middle coil support as shown in Figure 2-2.

e.Remove middle coil support.

f.Remove the mounting hardware from the coil.

g.Unsolder the two coil connections, one at the distributor 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 section 6.4. Evacuate the unit per section 6.5 and add refrigerant charge per section 6.6.2.

6.14 EVAPORATOR COIL HEATERS

WARNING

Before servicing unit, make sure the unit circuit breakers (CB-1 & CB-2) and the start-stop switch (ST) are in the OFF position, and that the power plug and cable are disconnected.

a.Remove the lower access panel (Figure 2-1) by removing the T.I.R. locking device lockwire and mounting screws.

b.Determine which heater(s) need replacing by checking resistance on each heater as shown in section 1.4.e.

c.Remove hold-down clamp securing heaters to coil.

d.Lift the “U” or “W” portion of the heater (with the opposite end down and away from coil). Move heater left (or right) enough to clear the heater end support.

6.15 EVAPORATOR FAN AND MOTOR ASSEMBLY

The evaporator fans circulate air throughout the container by pulling air in through 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 the refrigeration unit into the container. (Refer to section 2.3.) The fan motor bearings are factory lubricated and do not require additional grease.

To Replace the Evaporator Fan Assembly:

WARNING

Always turn OFF the unit circuit breakers (CB-1 & CB-2) and disconnect main power supply before working on moving parts.

a.Remove upper access panel (see Figure 2-1) by removing mounting bolts and T.I.R. locking device. Reach inside of unit and remove the Ty-Rap securing the wire harness loop. Then unplug the connector by twisting to unlock and pulling to separate.

b.Loosen four 1/4-20 clamp bolts that are located on the underside of the fan deck at the sides of the of the fan assembly. Slide the loosened clamps back from the fan assembly.

c.Slide the fan assembly out from the unit and place on a sturdy work surface.

To disassemble the Evaporator Fan Assembly:

1.Attach a spanner wrench to the two 1/4-20 holes located in the fan hub. Loosen the 5/8-18 shaft nut

T-268-07 6-16