Table of Contents
Advertisement
6.15.3 Assemble The Evaporator Fan Assembly
a. Assemble the motor and plastic spacer onto the stator.
When removing the black nylon evaporator fan
blade, care must be taken to assure that the
blade is not damaged. In the past, it was a com-
mon practice to insert a screwdriver between
the fan blades to keep it from turning. This prac-
tice can no longer be used, as the blade is made
up of a material that will be damaged. It is rec-
ommended that an impact wrench be used
when removing the blade. Do not use the im-
pact wrench when reinstalling, as galling of the
stainless steel shaft can occur.
b. Apply Loctite to the 1/4-20 x 3/4 long bolts and torque
to 0.81 mkg (70 inch-pounds).
c. Place one 5/8 flat washer on the shoulder of the fan
motor shaft. Insert the key in the keyway and lubricate
the fan motor shaft and threads with a graphite-oil
solution (such as Never-seez).
d. Install the fan onto the motor shaft. Place one 5/8 flat
washer with a 5/8-18 locknut onto the motor shaft and
torque to 40 foot-pounds.
e. Install the evaporator fan assembly in reverse order
of removal. Torque the four 1/4-20 clamp bolts to
0.81 mkg (70 inch-pounds). Connect the wiring con-
nector.
f. Replace access panel making sure that panel does
not leak. Make sure that the TIR locking device is
lockwired.
6.16 EVAPORATOR FAN MOTOR CAPACITORS
The single phase evaporator fan motors are of the
permanent-split capacitor type. The motor is equipped
with one capacitor used in the high speed circuit.
6.16.1 When To Check For A Defective Capacitor
a. Fan motor will not change speed. For example: in the
conventional perishable mode, the motors should run
in high speed. In the economy perishable mode they
should switch speeds and in the frozen mode, the mo-
tors should run in low speed.
The evaporator fan motors will always start in
high speed.
b. Motor running in wrong direction (after checking for
correct wiring application).
c. Motor will not start, and IP-EM's are not open.
T-334
Downloaded from
ManualsNet.com
NOTE
NOTE
search engine
6.16.2 Removing The Capacitor
Make sure power to the unit is OFF and
power plug disconnected before removing
capacitor(s).
The capacitors are located on the motor and above the
evaporator fan deck; they may be removed by two
methods:
1. If container is empty, open upper rear panel of the
unit. The capacitor may be serviced after discon-
necting power plug.
2. If container is full, turn the unit power OFF and dis-
connect power plug. Remove the evaporator fan
motor access panel. (See Figure 2--1). For removal
of the evaporator fan assembly, refer to section 6.15.
With power OFF discharge the capacitor
before disconnecting the circuit wiring.
6.16.3 Checking The Capacitor
If the capacitor is suspected of malfunction, you may
choose to simply replace it. Direct replacement requires
a capacitor of the same value. Two methods for
checking capacitor function are:
1. Volt-ohmmeter set on RX 10,000 ohms:
Connect ohmmeter leads across the capacitor
terminals and observe the meter needle. If the capacitor
is good, the needle will make a rapid swing toward zero
resistance and then gradually swing back toward a very
high resistance reading.
If the capacitor has failed open, the ohmmeter needle
will not move when the meter probes touch the
terminals. If the capacitor is shorted, the needle will
swing to zero resistance position and stay there.
2. Capacitor analyzer:
The function of the analyzer is to read the microfarad
value of a capacitor and to detect insulation breakdown
under load conditions. The important advantages of a
analyzer are its ability to locate capacitors that have
failed to hold their microfarad ratings, or those that are
breaking down internally during operation. It is also
useful in identifying capacitors when their microfarad
rating marks have become unreadable.
6.17 VALVE OVERRIDE CONTROLS
Controller function code Cd41 is a configurable code
that allows timed operation of the automatic valves for
troubleshooting. Three test sequences (Table 6--2 ) are
provided. The first, capacity mode (CAP), allows
alignment of the unloader and economizer solenoid
valves in the standard, unloaded and economized
operating configurations. The second, SMV % Setting
(SM) allows opening of the suction modulating valve to
various percentages and the third, Oil Valve Setting
(OIL) allows opening or closing of the oil return solenoid
valve.
A fourth selection is also provided to enter a time period
of up to three minutes, during which the override(s) are
active. If the timer is active, valve override selections will
6--16
WARNING
WARNING
Advertisement
Table of Contents
