American Aldes DH-100V - Manual (Page 5)

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 removed
before weighing in the new charge. Refer to the unit
nameplate for the correct charge weight and refrigerant
type.
5.5 Blower Replacement
The centrifugal blower has a PSC motor and internal
thermal overload protection. If defective, the complete
assembly must be replaced.
1.
Unplug the power cord.
2. If an outlet duct is connected to the unit, remove it.
3. Remove the cabinet side.
4. Remove the 4 screws holding the electrical box
located next to the blower.
5. Disconnect the blower leads. Black from the blower
switch, and white the run capacitor.
6. Unbolt the blower capacitor from the blower motor
(required for removal clearance). Pull the oil tubes
out of the motor.
7. Remove the nuts & bolts holding the blower outlet
flange to the cabinet end and remove the blower.
8. Reassembling with the new blower is the above
procedure reversed.
5.6 Compressor/Capacitor
Replacement
This compressor is equipped with a two terminal external
overload, run capacitor, but no start capacitor or relay.
See Fig. 2.
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 blower runs but the
compressor does not with the blower switch OFF and
the humidity control ON.
1.
Unplug the unit, remove the cabinet side (with two
screws in center) 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, the
high-pressure control or relay are open or there is 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, 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 indi-
cates an open start winding. The compressor must
be replaced. Normal start winding resistance 3 to 7
ohms.
5.
Compressor terminals C and R: No continuity indi-
cates 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 com-
pressor must be replaced.
9.
Disconnect the yellow wires from the 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 capaci-
tor. Plug in and turn on the unit. If the compressor
fails to start, replace the run capacitor.
11. If the unit still doesn't 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 in
the compressor motor, the resulting high temperature
arc causes a portion of the refrigerant oil mixture to
break down into carbonaceous sludge, a very corrosive
acid, and water. These contaminants must be carefully
removed otherwise even small residues will attack
replacement compressor motors and cause failures.
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