MODEL 1750/1770 DEHUMIDIFIER
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.
Moisture 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:
Typical “Whole-Building” Operation:
In the
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.
MODEL 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
PRODUCT SPECIFICATIONS
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 | |
Relative Humidity Storage Conditions | 0% to 100% |
Supply Voltage (DC from Model 1700/1720 Control Board) | 12 VDC |
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
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.
RESEARCH PRODUCTS RESERVES THE RIGHT TO CHANGE SPECIFICATIONSWITHOUT NOTICE.
PO Box 1467 • Madison, WI
Form No. 4251 05.09 | ©2009 Research Products Corporation |
| Printed in USA |
