System Checkout - Aprilaire 1750A Installation Instructions Manual

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 . Wait 5 seconds then 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 3 minutes 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 .
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 SETTING
1 . Use the control knob on the unit to set the desired dryness level .
• B ased on indoor temperature, use Table 6 to determine the control knob setting to achieve the desired humidity level .
• F or most installations, start with a setting in the NORMAL range. See figure 33 .
• M oving the knob clockwise towards MORE will increase dehumidifier run time, allowing for lower humidity levels.
• M oving the knob counterclockwise towards LESS will decrease dehumidifier run time, allowing for higher humidity levels.
2 . Reference the Installation Instructions for the Model 76 Control, Model 8910 Home Comfort Control
TAblE 6 – %RH (± 5%) based on Control Knob Setting & Indoor Temperature
Control Knob Setting
& Dew Point
1 – Less, 65°F DP
2 – 60°F DP
3 – Normal, 56°F DP
4 – Normal, 52°F DP
5 – Normal, 48°F DP
6 – 44°F DP
7 – More, 40°F DP
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 wiring access door and rotate the CYCLE TIME potentiometer clockwise to the TEST
position . See figure 34 .
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 out of 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 .
22
Indoor Temperature
65°f 70°f
84%
86% 73%
74% 63%
64% 54%
55% 46%
47% 39%
40% 34%
75°f 80°f
71% 60%
61% 52%
53% 45%
45% 39%
39% 33%
33% 28%
28% 24%
fIGURE 33 – Control Knob Setpoint
, or Third-Party Control for setting adjustments .
™
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 .
• T he %RH values are ± 5% and are to be
used as a GUIDE ONly for initial set-up .
• I ndoor temperature is measured at the inlet
to the dehumidifier .
fIGURE 34 – Ventilation Test
VENTILATION TEST
30
MIN.
0
MIN
OFF
CYCLE TIME
90-1327
60
MIN.
TEST
90-1538