Ultra-Aire SD12 Installer’s & Owner’s Manual
20
7.9 Defrost Thermostat
The defrost thermostat is attached to the refrigerant suction tube
between the accumulator and the compressor. It will automatically
shut the condensing unit off if the low side refrigerant temperature
drops due to excessive frost formation on the evaporator coil. The
dehumidifier impeller fan will continue to run, causing air to flow
through the evaporator coil and melt the ice. When the ice has
melted, the evaporator temperature will rise and the thermostat will
restart the condensing unit.
7.10 Electric Ventilation Damper
The damper will open when ventilation is called for, allowing fresh
air into the structure through the fresh air inlet duct. The electric
ventilation damper will remain closed when ventilation is not
activated in order to prevent over-ventilating the structure when
the unit is dehumidifying or recirculating the indoor air. The electric
ventilation damper operates on 24 Vac from the control circuit. DO
NOT connect high voltage to the damper motor or damage to the
motor will result. DO NOT force the blade of the damper by hand or
damage to the damper motor may result.
The damper opens in one direction only. The damper rotates very
slowly, allow sufficient time for the damper to cycle. The damper
will take approximately 1 minute to cycle from closed to open or
from open to closed.
FOR HVAC INSTALLER ONLY
If the electric ventilation damper fails to operate:
1. Check that the wiring is correct and that voltage is present at the
damper motor.
2. Check for any obstruction inside the damper. If the electric
ventilation damper fails to operate after performing these checks, it
must be replaced.
7.11 Condensate Pump Kit
An optional condensate pump kit is available from the factory for use
with the Ultra-Aire SD12. Condensate is automatically pumped to a
remote location when the water level in the pump’s reservoir rises to
close the float switch.
The pump also contains a safety float switch. The white leads from this
switch extend from beneath the pump cover. This switch should be in-
stalled in series with the field wire that connects the blue (#7) lead from
the Ultra-Aire SD12 to the dehu terminal on the control panel. Contact a
certified electrician to install the Safety Overflow Switch (optional).
If the pump fails, this switch opens the condensing unit control circuit
and stops water production before the reservoir overflows. The Ultra-Aire
SD12 will continue to ventilate or circulate air as normal, but will not
dehumidify until this switch closes.
LINE
NEUTRAL
DEHU.
RELAY
BLOWER
RELAY
BLOWER
XFMR
DEHU.
RELAY
COIL
BLOWER
RELAY
COIL
DEFROST
T-STAT
L. PRESS
SWITCH
RUN
CAP.
1
COMPRESSOR
COND.
RELAY
COND.
RELAY
COIL
115 VAC
LINE NEUTRAL
BLK
RED
BRN
WHT
BLK
BRN
RED
WHT
RUN
CAP.
WHT
BLK
BLK
3
4
5
6
7
RUN
CAP.
BLOWER
24VAC SIGNAL
FROM DEHU.
NC
NO
YEL-6
BLU-7
GRN-5
PNK
-3
WHT
-4
RED-1
YEL-2
BLK-9
BLK-8
BLK
BLK
BLK-3
WHT
-5
BLK-2
BL
U-2
115V
24V
COM
COM
BRN-3
BLK-1
BLK
-1
+24VAC
DEHU
FAN
COM
CUSTOMER
CONTROL
WIRING
BLU
YEL
GRN
RED
BLK
BLK
24VAC TO
COND.
GRN-4
NO
BLK-5
VIO-6
2
S
C
R
1
3
FIGURE 17A: DEHUMIDIFIER WIRING DIAGRAM
FIGURE 17B: CONDENSING UNIT
WIRING DIAGRAM
Summary of Contents for SD12
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