B Replacing A Burned Out Compressor; C Replacing A Compressor, Nonburn Out; Remote Controls; A Humidity Control - Ultra-Aire SD12 Installer's & Owner's Manual

FOR HVAC INSTALLER ONLY
can be used to test 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.

7.7B Replacing a Burned Out Compressor

WARNING!
IMPROPER INSTALLATION, ADJUSTMENT, AL-
TERATION, SERVICE OR MAINTENANCE CAN CAUSE PERSONAL INJURY,
LOSS OF LIFE, OR DAMAGE TO PROPERTY.
IMPORTANT!
INTENTIONAL VENTING OF REFRIGERANT (CFCs, HCFCs, AND HFCs)
AS OF JULY1, 1992. APPROVED METHODS OF RECOVERY, RECYCLING
OR RECLAIMING MUST BE FOLLOWED. FINES AND/OR INCARCERATION
MAY BE LEVIED FOR NONCOMPLIANCE.
The refrigerant and oil mixture in a compressor is chemically very stable
under normal operating conditions. However, when an electrical short oc-
curs 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.
2. Remove and properly dispose of the system charge. DO NOT vent the
refrigerant 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. Con-
taminants 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 while running.
Sludge and acid have been pumped throughout the system. Several
changes of the liquid and suction filter/driers may 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 over-
sized liquid line filter.
In a running burn out, install an oversized suction line filter/drier be-
tween the accumulator and compressor. Thoroughly flush the accumu-
THE CLEAN AIR ACT OF 1990 BANS THE
lator 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.
Once the evacuation is complete charge the system per section 7.4.
8. Operate the system for a short period of time, monitoring the suc-
tion 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.

7.7C Replacing a Compressor, Nonburn Out

Remove the refrigerant from the system. Replace the compressor
and liquid line filter/drier. Refer to Section 3.5 to check for leaks.
Remove the charge and charge the system per section 7.4. Operate
the system to verify performance.

7.8 Remote Controls

The Ultra-Aire SD12 is controlled by 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 you purchased. If the Ultra-
Aire SD12 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 SD12. Check the connections
between the Ultra-Aire SD12, the control panel, and the field control
wiring.

7.8A 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 screen
set point.
The Ultra-Aire SD12 is equipped with an automatic defrost mecha-
nism. If the Ultra-Aire SD12 operates in conditions that develop frost
on the evaporator, it will sense the frost build-up and automatically
defrost the evaporator. The Ultra-Aire SD12 may not appear to be
operating correctly during the defrost sequence, but once the defrost
sequence is complete, the Ultra-Aire SD12 will resume dehumidify-
ing.
7.8B Programmable Ventilation Timer – DEH3000/3000R
The ventilation timer controls the dehumidifier impeller fan and the
motorized fresh air damper. When the ventilation timer is activated,
the Ultra-Aire SD12 will circulate the indoor air, and bring in fresh
air from outside. The ventilation timer should be set for the required
ventilation of the residence. The home should be ventilated with
fresh air as suggested by applicable codes and standards.
If the Ultra-Aire SD12 fails to ventilate as expected, check that the
time on the timer is correct. Also check the programs on the timer to
be sure that the timer is calling for ventilation at the correct times.
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Ultra-Aire SD12 Installer's & Owner's Manual