Aprilaire 1750A Dehumidifier User Manual


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SYSTEM CHECKOUT
DEHUMIDIFICATION
1. Check the wiring to the HVAC equipment and any accessories if applicable.
2. Plug unit in and turn on/off switch to ON.
3. Rotate the main control knob clockwise to the TEST position.
4. If set up correctly, the dehumidifier blower will turn on and the dehumidifier damper
output will turn on. After 30 seconds the dehumidifier compressor will turn on. The blower
and compressor will remain on for 1 minute in TEST mode. After 1 minute has elapsed,
the dehumidifier blower and compressor will turn off and the dehumidifier damper output
will turn off. NOTE: If the minimum off time for the compressor has not expired when
the test mode is initiated, the compressor will not turn on until the minimum off time has
been met. If the blower or compressor fails to turn on, refer to the Troubleshooting Guide.
5. The Status LED will blink red and green alternately if the control knob has been left in
TEST after the compressor has turned off.
ADJUSTING DEHUMIDIFIER SET POINT
1. Use the control knob on the unit to set the desired dryness level.
•Basedonindoortemperature,useTable 6 to determine the control knob setting to achieve the desired humidity level.
•Formostinstallations,startwithasettingintheNORMALrange.See Figure 29.
•MovingtheknobclockwisetowardsMOREwillincreasedehumidifierruntime,allowingforlowerhumiditylevels.
•MovingtheknobcounterclockwisetowardsLESSwilldecreasedehumidifierruntime,allowingforhigherhumiditylevels.
2. Reference Model 70 Living Space Control or Third-Party Control’s Installation Instructions for start-up with a separate control.
Note: There is a 6 minute delay after power up when using a Model 70.
FIGURE 29 – Control Knob Setpoint
90-1327
EXAMPLE: At an indoor temperature of 75°F
and a control knob setting of 3 (56°F DP),
the dehumidifier will work to achieve a 53%
humidity level.
•The%RHvaluesare±5%andaretobe
used as a GUIDE ONLY for initial set-up.
•Indoortemperatureismeasuredattheinlet
to the dehumidifier.
TABLE 6 – %RH (± 5%) Based on Control Knob Setting & Indoor Temperature
Control Knob Setting
& Dew Point
Indoor Temperature
65°F 70°F 75°F 80°F
1 – Less, 65°F DP 84% 71% 60%
2 – 60°F DP 86% 73% 61% 52%
3 – Normal, 56°F DP 74% 63%
53%
45%
4 – Normal, 52°F DP 64% 54% 45% 39%
5 – Normal, 48°F DP 55% 46% 39% 33%
6 – 44°F DP 47% 39% 33% 28%
7 – More, 40°F DP 40% 34% 28% 24%
VENTILATION
1. Verify 24 VAC is applied in series with the normally-closed damper and connected to the VENT
DAMPER terminals on the dehumidifier control board.
2.RemovethecontroldoorandrotatetheCYCLETIMEpotentiometerclockwisetotheTESTposition.
See Figure 30.
3. If set up properly, the HVAC blower will turn on and the ventilation damper will open. The HVAC
blower will remain on and the ventilation damper will remain open for 1 minute or until the dial
is turned from the TEST position. DO NOT leave CYCLE TIME set to TEST. If the HVAC blower
fails to turn on or the damper fails to open, refer to the Troubleshooting Guide.
FIGURE 30 – Ventilation Test
MIN.
30
MIN
MIN.
600
CYCLE TIME
TEST
OFF
VENTILATION TEST
90-1538
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