Therma-Stor Products Group Ultra-Aire 100V - Manual (Page 12)

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.
7.6B 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 could
be toxic and highly acidic. If no acid odor is present, skip down
to the section on changing a non-burn out compressor.
2. Remove and properly dispose of the system charge. DO NOT
vent the refrigerant indoors or allow it to contact your eyes
or skin.
3. Remove the burned out compressor. Use rubber gloves if there
is any possibility of contacting the oil or sludge.
4. To facilitate subsequent steps, determine the type of burn
out that occurred. If the discharge line shows no evidence
of sludge and the suction line is also clean or perhaps has
some light carbon deposits, the burn out occurred while the
compressor was not rotating. Contaminants are therefore
largely confined to the compressor housing. A single
installation of liquid and suction line filter/driers will probably
clean up the system. If sludge is evident in the discharge line,
it will likely be found in the suction line. This indicates the
compressor burned out will running. Sludge and acid have
been pumped throughout the system. Several changes of the
liquid and suction filter/driers will probably be necessary to
cleanse the system.
5. Correct the system fault that caused the burn out. Consult the
factory for advice.
6. Install the replacement compressor with a new capacitor and
an oversized liquid line filter. In a running burn out, install an
oversized suction line filter/drier between the accumulator and
compressor. Thoroughly flush the accumulator with refrigerant
to remove all trapped sludge and to prevent the oil hole from
becoming plugged. A standing burn out does not require a
suction line filter/drier.
7. Evacuate the system with a good vacuum pump and
accurate vacuum gauge. Leave the pump on the system for
at least an hour.
8. Operate the system for a short period of time, monitoring the
suction pressure to determine that the suction filter is not
becoming plugged. Replace the suction filter/drier if pressure
drop occurs. If a severe running burn out has occurred, several
filter/driers may have to be replaced to remove all of the acid
and moisture.
NOTE: NEVER use the compressor to evacuate
the system or any part of it.
7.6C Replacing a Compressor, Nonburn Out
Remove the refrigerant from the system. Replace the compressor
and liquid line filter/drier. Charge the system to 50 PSIG and check
for leaks. Remove the charge and weigh in the refrigerant quantity
listed on the nameplate. Operate the system to verify performance.
7.7 Remote Controls
The Ultra-Aire is controlled by devices mounted on a panel that is
remote from the unit. You may or may not have the devices listed
below depending on the model of the remote control panel that
you purchased. If the Ultra-Aire fails to operate as desired, always
check the settings of the controls to insure that they are correct.
Check that the controls are receiving 24Vac from the Ultra-Aire.
Check the connections between the Ultra-Aire, the control panel,
and the field control wiring.
7.7A Humidity Control
The humidity control is an adjustable switch that closes when the
relative humidity of the air in which it is located rises to the dial set
point. It opens when the RH drops 4 to 6% below the set point. If the
FOR HVAC INSTALLER AND HOMEOWNER
12 Ultra-Aire 100V Installer’s & Owner’s Manual