Therma-Stor Products Group PHOENIX 300 - Manual (Page 6)

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4.5 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. Remove the cabinet front (6 screws).
3. Disconnect the blower leads.
4. Pull the oil tubes out of the motor.
5. Tip the unit on its back. From the bottom, remove
the 2 screws that fasten the blower housing to
the base.
6. Remove the four screws holding the blower outlet
flange to the cabinet end.
7. Remove the blower. Use care to avoid hooking
wiring, tubing or electrical components.
8. Reassembling with the new blower is the above
procedure reversed.
4.6 Compressor/Capacitor
Replacement
This compressor is equipped with a two terminal
external overload, run capacitor, but no start capacitor
or relay (see Fig. 3).
CAUTION-ELECTRICAL SHOCK HAZARD: Electrical
power must be present to perform some tests; these
tests should be performed by a qualified service
person.
4.6A Checking Compressor Motor Circuits
Perform the following tests if the blower runs but the
compressor does not with the power switch ON.
1. Turn the power switch OFF and unplug the unit,
remove the cabinet front (6 screws).
2. Plug in the unit and turn the power switch ON.
Use a voltmeter to check for 110 to 120 volts
between (a) the relay terminal that the black wire
from the compressor connects to and (b) the
capacitor terminal with the (3) white wires & (1)
red wire connected. If voltage is present, go to
step 3. If no voltage, the low pressure control, the
time delay or the 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. Turn the power switch OFF and 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
indicates an open start winding; the compressor
must be replaced.
5. Compressor terminals C and R: No continuity
indicates an open run winding; the compressor
must be replaced.
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 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 will provide greater starting torque. If this does
not work, the compressor has an internal
mechanical defect and must be replaced.
4.6B 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.
The following procedure is effective only if the system
is monitored after replacing the compressor to insure
that the clean up was complete.
1. This procedure assumes that the previously listed
compressor motor circuit tests revealed a shorted
or open winding. If so, cautiously smell the
refrigerant from the compressor service port for
the acid odor of a burn out. WARNING: The gas