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RESEARCH PRODUCTS RESERVES THE RIGHT TO CHANGE SPECIFICATIONS WITHOUT NOTICE.
PRINCIPLE OF OPERATION
The Aprilaire Model 1750/1770 is designed to dehumidify the air
coming into the unit by passing the incoming air over a cooling
coil to drop the air temperature and dewpoint of the air.
M
oisture is removed from the air and drained out of the unit to a
common floor or waste drain. The air is then reheated in the
condenser coil and exits the unit.
It dehumidifies until a preset dewpoint setpoint is reached, then
shuts off until periodic sampling determines a need for operation.
The Model 1750 can be installed in two types of configurations:
“Whole-Building” or “Localized/Spot”.
Typical “Whole-Building” Operation:
In the “Whole-Building
” configuration, the Model 1750/1770 is
used to dehumidify the entire building. In this application, the
Model 1750/1770 must be wired to the HVAC equipment blower.
In this configuration, the unit can be installed two ways:
1. Pulling air from the occupied space, through the dehumidifier
and discharging it into the supply duct/plenum of the HVAC
system.
2. In a bypass method, pulling air from the return, through the dehumidifier and discharging it into the supply duct/plenum of the HVAC system.
In order to check the dewpoint of the incoming air, the 1750/1770 must “sample” the air. To do this, the 1750/1770 will turn on with the first HVAC
equipment blower call in each selectable cycle (time) period. In the event that the blower is on continuously or during occupied times, the
dehumidifier will sample at the first available opportunity within the cycle period. If no HVAC equipment blower call occurs during the cycle period,
the 1750/1770 will activate it’s internal blower 3 minutes prior to the end of the cycle to enable it to sample the air. If the incoming air is above the
desired set point, the dehumidifier compressor will turn on. If the HVAC equipment blower call ends prior to the dehumidification set point becoming
satisfied, the 1750/1770 will continue to run and operate until the set point is met. The unit can be set to “sample” the air every 30 minutes, 1 hour, 2
hours, or 3 hours.
Typical “Localized/Spot” Operation:
In the “Localized/Spot
” configuration, the Model 1750/1770 is used to dehumidify a specific room or location within the building.
In this configuration, the unit can be installed two ways:
1. Pulling air from the occupied space, through the dehumidifier, and discharging it directly back into the occupied space. This is typically done
using wall grilles or ceiling diffusers.
2. Pulling air from the occupied space, through the dehumidifier, and discharging it into the supply duct serving the same occupied space that the air
was pulled from. This allows the warmer, dehumidified air to mix with cooler supply air from the HVAC System when the HVAC system air
conditioning is on.
If the Model 1750/1770 is wired to the HVAC equipment blower, the operation is the same as the typical “Whole-Building” operation.
If the Model 1750/1770 is operated independently of the HVAC equipment blower, the unit will use its internal blower to both sample the air and
provide the air flow necessary to distribute the air into the space.
MODEL 1750/1770 DEHUMIDIFIER
PO Box 1467 • Madison, WI 53701-1467 • Phone 800/334-6011 • Fax 608/257-4357 • www.aprilairecontractor.com
©2009 Research Products Corporation
Printed in USA
Form No. 4251 05.09
M
ODEL 70
OCCUPIED SPACE CONTROL
• On/Off buttons
• Displays set point indication bars
and measured RH in the area
• Senses dewpoint in the
occupied space
• Adjustable to achieve “more” or
“less” dry conditions
Low Dewpoint Control Level ("MORE DRY" or 7 bars on display) 40°F
High Dewpoint Control Level ("LESS DRY" or 1 bar on display) 65°F
Temperature Sensor Range 40°F to 100°F
Relative Humidity Sensor Range 30% to 100%
Temperature Storage Range -30°F to 120°F
Relative Humidity Storage Conditions 0% to 100%
Supply Voltage (DC from Model 1700/1720 Control Board) 12 VDC
PRODUCT SPECIFICATIONS