11
6. Turn on the fan switch; the fan should run. Turn
off the fan switch.
7. Turn on the humidity control; the compressor and
fan should run.
8. If these tests work, the problem is most likely in
the field control wiring.
5.4 Refrigerant Charging
If the refrigerant charge is lost due to service or a leak,
a new charge must be accurately weighed in. If any of
the old charge is left in the system, it must be
recovered before weighing in the new charge. Refer to
the unit nameplate for the correct charge weight and
refrigerant type.
5.5 Fan Replacement
The motorized impeller is a unitary assembly
consisting of the motor and impeller. If defective, the
complete assembly must be replaced.
1. Unplug the power cord.
2. Remove the cabinet access panel.
3. Remove the screw attaching the fan support
bracket to the base.
4. Disconnect the fan leads inside the electric box.
5. Push up on the inlet ring and pull the fan and fan
support bracket to the right, then up and out of
the unit.
6. Remove the defective fan from the bracket and
replace with new fan.
7. Reassemble the new fan by reversing the above
procedure.
5.6 Compressor/Capacitor
Replacement
This compressor is equipped with a two terminal
external overload and a run capacitor, but no start
capacitor or relay (See Figure 4).
CAUTION-ELECTRICAL SHOCK HAZARD:
Electrical
power must be present to perform some tests. These
tests should be performed by a qualified service
person.
5.6A Checking Compressor Motor Circuits
Perform the following tests if the fan runs but the
compressor does not with the fan switch and
ventilation timer OFF and the humidity control ON.
1. Unplug the unit; remove the cabinet side and the
electrical connection cover on the compressor top.
2. Plug in the unit and turn the humidity control to ON.
Check for 110 volts from compressor terminal
R
to
overload terminal
3
using an AC voltmeter. If
voltage is present, go to step 3. If no voltage, there
may be a loose connection in the compressor
circuit. Test each component for continuity. See
the appropriate section if a defect is suspected.
3. Unplug the unit, and then disconnect the red and
yellow wires from compressor terminals
R
&
S
.
Using an ohmmeter check continuity between the
points listed below.
4. Compressor terminals
C
and
S
:
No continuity indicates an open start winding. The
compressor must be replaced. Normal start
winding resistance is 3 to 7 ohms.
5. Compressor terminals
C
and
R
:
No continuity indicates an open run winding. The
compressor must be replaced. Normal run winding
resistance is .5 to 2 ohms.
6. Compressor terminal
C
and overload terminal
1
:
No continuity indicates a defective overload lead.
7. Overload terminals
1
and
3
:
If there is no continuity, the overload may be
tripped. Wait 10 minutes and try again. If there is
still no continuity, it is defective and must be
replaced.
8. Compressor terminal
C
and compressor case:
Continuity indicates a grounded motor. The
compressor must be replaced.
9. Disconnect the wires from the run capacitor. Set the
ohmmeter to the Rx1 scale. The capacitor is shorted
and must be replaced if continuity exists across its
terminals. If there is no needle movement with the
meter set on the Rx100000 scale, the capacitor is
open and must be replaced.
10. Reconnect the wires to the compressor and
capacitor. Plug in and turn on the unit. If the
compressor fails to start, replace the run capacitor.
11. If the unit still does not start, adding a hard-start kit
(relay & capacitor) will provide greater starting
torque. If this doesn't work, the compressor has an
internal mechanical defect and must be replaced.
5.6B Replacing a Burned Out Compressor
The refrigerant and oil mixture in a compressor is
chemically very stable under normal operating
conditions. However, when an electrical short occurs
