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tion of condensation on the inside walls of the
HEAT position, the remaining heaters are ener-
tubing. Plug or cap all openings as a part is re-
g i z e d , providing maximum heating capacity
moved to minimize the entry of dirt and moisture.
(12,000 BTUH).
c. Use a silver solder on all soldered connections.
5-3. Repair Procedures
Easy-Flo silver solder (or equivalent) with a 50
percent silver capacity and a melting point of ap-
a. If the system must be opened for repair or
proximately 1160F. is recommended. Continually
replacement of parts, connect a hose line to the
pass dry nitrogen through the tubing or connec-
suction service valve and purge the refrigerant to
t i o n s being soldered to prevent formation of
an outside area.
harmful copper oxides.
b. After purging the system allow the tubing to
d. No metal to metal contact on capillary tubes
warm to the ambient temperature before opening
is allowable; use tape to prevent such contact.
the system; this delay will help prevent the forma-
Section Il. REMOVAL AND INSTALLATION OF COMPONENTS
c. Disassembly. Refer to figure 5-2, and disas-
5-4. Blower Fan Motor
semble the blower motor.
a. On-Equipment Testing. Before removing the
d. Testing.
motor for replacement, test the motor windings
for opens and grounds:
(1) Overload protector. Disconnect the elec-
(1) Disconnect receptacle connector from
trical leads from the overload protector. Test the
motor junction box.
protector with a multimeter set on OHMS. If con-
(2) Test continuity across each combination
tinuity does not exist, replace the overload pro-
of two motor terminals. Lack of continuity indi-
tector.
cates an open winding.
(2) Motor bench test. Perform the growler
(3) Place one contact of the tester against
tests on the stator as instructed in TM 5764. Re-
motor housing and the other against one of the
place a defective stator.
motor terminals. If a circuit is indicated, the
e. Cleaning, Inspection and Repair.
motor is grounded.
(4) Test the motor stator for insulation resis-
(1) Clean all parts with a cloth dampened in
tance as instructed in TM 5-764. The insulation
approved cleaning solvent.
resistance should measure not less than 0.5 meg-
(2) Inspect the stator housing for cracks,
ohms for the motor on either model.
breaks, or other defects. Replace a damaged or
Note. The resistance measurement should be
defective housing.
used only as a general guide, taking into consideration the
(3) Inspect bearings for pits, scoring, wear,
accuracy of the instrument used, test lead resistance, and
ambient temperature at time of test. If more precise
and out-of-round. Replace worn or defective bear-
measurement is required, an instrument such as a Kelvin
ings.
or Whetstone bridge should be used, or comparative
(4) Inspect the rotor shaft for cracks, wear,
measurement between the suspected component and a like
item known to be good should be utilized. In all cases where
and misalinement. Replace a damaged or defective
a megohmeter is used for testing, make certain that the
rotor. -
unit is thoroughly dry.  Wet condemnation tolerances
(5) Inspect the rotor for cracks, breaks, and
should be considered.
damaged laminations. Replace the rotor and stator
(5) Connect the motor leads to a proper
if they are damaged, Replace the stator if it does
source of power. Use a hook-type ammeter and
not meet test standards (d above).
read the amperage flowing in each of the motor
(6) Inspect all threaded parts for damage.
leads. On Model CE20VAL4 the ammeter should
Replace as necessary.
indicate between 1.45 and 2.2 amperes at no load.
The ammeter should indicate between 1.75 and 2,5
f. Reassembly. Refer to figure 5-2, and reas-
amperes at no load on Model CE20VAL6. Start
semble the blower motor.
the unit and check the ammeter reading. If the
g. Installation. Refer to paragraph 3-25, and
readings are not equal, the motor bearings are
install the blower motor.
worn or the stator winding is defective. Follow
the instructions in c below and disassemble the
5-5. Power Receptacle Connector
motor for further testing and repair.
b. Removal. Refer to paragraph 332, and
a. Removal. Refer to figure 53, and remove the
remove blower motor.
power receptacle connector.
AGO 20053A

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