Section XII. MAINTENANCE OF T H E ELECTRICAL SYSTEM
non box by removing the four screws which secure
it to the top of the junction box.
T h e heart of the air conditioner electrical system is
(3) Remove the knob from the thermostat by
the junction box and control panel which are
loosening the two set screws with a .050 Hexagon
mounted behind the front access panel. Com-
ponents not integral to these two electrical boxes
( 4 ) Remove the back panel of the control panel
are the fan motor and compressor, start/run
b y removing the four nuts and screws which secure
capacitors, electric heating elements, fan speed
it to the control panel.
relay, heater thermostat, solenoid valve coils, and
d. Complete Disconnection of Junction Box.
outside air thermostat, In addition to these com-
(1) Follow the steps outlined in Paragraph 4-
ponents there are three wiring harnesses in the air
35-b to partially remove the junction box.
conditioner to interconnect them to the junction
( 2 ) Disconnect the two electrical connectors on
b o x and control panel, It is necessary to remove the
the back left side of the junction box and the
junction box and control panels from the air
connector on the, left side of the control panel.
conditioner to service most of the components
( 3 ) Remove the hex head screw which secures
integral to them,
the front left corner of the casing to the bottom
4-36. Removal, Service and Installation of the
panel of the air conditioner and remove the elec-
Junction Box and Control Panel
trical ground wire.
a . General. It is necessary to completely remove
( 4 ) Remove the junction box and control panel
the junction box and control panel for access to
from the air conditioner.
some components located in the lower portion of
e . Servicing. Servicing consists of test, inspection
the air conditioner. The electrical connections
or replacement of defective electrical components
(three electrical connectors and the electrical
included in the junction box or control panel. All
ground wire) do not have to be disconnected for
gaskets and insulation should be inspected for
most servicing of the junction box and control
defects and proper adhesion to the metal surfaces
and re-glued or replaced as required. Check the
b. Removal of Junction Box for Servicing and
four captive screws on the junction box cover and
t h e four which secure the junction box to the right
( 1 ) Remove the front access panel (para 4-12).
and left side mounting brackets to insure that the
(2) Loosen the four screws which secure the
retaining washers are in place to retain the screws
junction box to its right and left hand mounting
in their respective mounting holes. Wiring har-
nesses and wire leads should be checked to insure
( 3 ) Loosen the two clamps located on the right
t h a t all connections are tight, the wire insulation is
end of the junction box which secure the circuit
s e r v i c e a b l e and that the wiring is routed and tied to
b r e a k e r actuator cable. Remove the end fitting core
p r e v e n t chafing on sharp edges or interference with
from the end of the actuator cable and slide the
cable up out of the two clamps which held it.
f Installation. Installation shall be in the reverse
(4) Remove the intake air grille (para 4-13)
order of removal.
and the air filter (para 4-21). Remove the clamp
4-37. Circuit Breaker
which secures the thermostat sensing bulb to the
a. Function. This is a two pole breaker with a
c a s e by removing the screw which secures it to the
mechanically interlocked auxiliary switch. The
circuit breaker opens if there is excessive current
(5) Slide the thermostat bulb through the
g r o m m e t located in the partition above the junction
elements. The auxiliary switch opens when the
b o x . Take care to insure that the capillary tube does
main poles open and de-energizes the low voltage
not become kinked or broken.
control system of the air conditioner.
(6) Remove the front cover from the junction
b. T e s t i n g . Remove the junction box from the air
box by loosening the four captive screws which
conditioner (para 4-36-b). Disconnect and tag all
secure it to the front flanges of the junction box.
w i r e leads. Check for continuity between each pair
(7) Slip the junction box with the control
o f wire terminals when the circuit breaker is closed
module attached out of the air conditioner casing.
and open circuit when open. Check for insulation
c. Removal of Control Panel for Servicing.
resistance between the three electrical circuits.
( 1 ) Follow the steps outlined in Paragraph 4-
L a c k of continuity when closed, open circuit when
3 5 - b to r e m o v e t h e j u n c t i o n b o x .
open or low insulation resistance between circuits
(2) Remove the control panel from the junc-