Aprilaire 1870 User Manual

Model 1870 & 1870W Dehumidifier

Owner’s Manual

PLEASE LEAVE THIS MANUAL WITH THE HOMEOWNER

Installed by: _________________________________ Installer Phone: _______________________ Date Installed: _______________

ON/OFF button

used to turn

dehumidifier on

and off

MODE button

used for optional

ventilation feature

Up/ Down

buttons used to

change humidity

setting

Dehumidifer Control

Inlet Filter Access

Door

Outlet

Drain Power

Switch

WHOLE HOME DEHUMIDIFICATION

The Aprilaire® Dehumidifier controls the humidity level in your entire home. A powerful blower inside the dehumidifier draws air into the cabinet,
filters the air and removes moisture, then discharges the dry air into the HVAC system or dedicated area of the home. Inside the cabinet, a
sealed refrigeration system removes moisture by moving the air through a series of tubes and fins that are kept colder than the dew point of
the incoming air. The dew point is the temperature at which moisture in the air will condense, much like what occurs on the outside of a cold
glass on a hot summer day. The condensed moisture drips into the dehumidifier drain pan to a drain tube routed to the nearest floor drain or
condensate pump. After the moisture is removed, the air moves through a second coil where it is reheated before being sent back into the home.
The air leaving the dehumidifier will be warmer and drier than the air entering the dehumidifier.

You can reduce the amount of humidity that enters the home by closing windows, doors, and fireplace flues when outdoor humidity is high,
and by drying clothes outside. Direct exhaust from kitchen vents and bath fans is the best means of controlling humidity due to cooking and
showers/baths. The dehumidifier is not designed to prevent window condensation in winter. Use ventilation to lower indoor humidity levels
in the winter.

SETTING THE DESIRED HUMIDITY LEVEL

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The dehumidifier on-board control will display the humidity setting when not running,
and displays the measured humidity when running.

The UP and DOWN arrow buttons allow the humidity level to be set from 40% to 80%
relative humidity. Use the ON/OFF button to turn the dehumidifier ON or OFF.

Set the control at 55%RH when first
installed. Allow the dehumidifier to run
until it reaches the setting before deciding
if you want to change the setting.

• Ifyouprefertheairtobemoredry,
decrease the humidity setting.

• Ifyouprefertheairtobelessdry,
increase the humidity setting.

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Your comfort is the best measure of how to adjust your setting. When first installed,
your dehumidifier has to remove all the moisture that is initially in your home. The
home acts like a sponge so the moisture in the materials of your home is at the same
level as the air. After drying the air, the materials of the home will release moisture
back into the air until they are again at the same level. As a result, it is not uncommon
for the dehumidifier to operate for an extended period when first installed.

HOW DOES THE DEHUMIDIFIER WORK?

ENERGY SAVINGS TIPS

EnergySavingsTip#1: Adjust the humidity
setting to be as high as is comfortable to
reduce dehumidifier run time. If it feels
clammy or “smells musty”, lower the humidity
setting. To save energy, turn the dehumidifier
to OFF when you open your windows, just as
you would with air conditioning.

EnergySavingsTip#2: If vacating your home
for an extended period in the summer, set the
RH at 55% and set your thermostat as high as
you are comfortable setting it to in the cooling
mode. Consult with appropriate professionals
regarding the highest temperature that is safe
for your pets or possessions. This will keep the
humidity at a controlled level while minimizing
the amount of cooling energy used.

Once per hour the dehumidifier will measure the humidity level of the air and compare it to the humidity setting. If the humidity in your home is
higher than the setting, the dehumidifier will dehumidify the air until the humidity level drops below the setting. NOTE: The dehumidifier will
continue to dehumidify until the humidity level is 3%RH below the setting.

When the dehumidifier turns on, the blower circulates the air for 3 minutes before measuring the
humidity level of the air. The on-board control will display AIR SAMPLING, along with the measured
humidity on the control screen.

If the humidity of the air is higher than the setting, the compressor turns on and the control will display
DEHUMIDIFYING, along with the measured humidity on the control screen.

Your dehumidifier is equipped with two features that protect against unwanted energy consumption. Defrost is a normal operating mode that
helps to prevent significant ice formation on the refrigeration system coil. The dehumidifier display will show “DEFROSTING” when operating
in this mode. This mode can occur when there is not enough air moving through the dehumidifier or if the temperature and/or humidity of
the incoming air is too low. The second protection feature is the E8 code. E8 on the dehumidifier display indicates that the air entering the
dehumidifier is below 50°F or above 104°F, or the dew point of the incoming air is below 40°F. There would be a significant reduction in
dehumidifier efficiency if the dehumidifier operated outside of these conditions. Low dew point conditions can be seen in some basements
or crawl spaces and usually occur in the Winter and Spring months. The dehumidifier continues to monitor the incoming air and when the
conditions are within the operating range, E8 will be removed from the display and dehumidification will begin as needed.

OPTIONAL – HEATING AND COOLING SYSTEM BLOWER OPERATION

Your installing contractor may have configured the dehumidifier to turn on the heating and cooling system blower when the dehumidifier turns on
to allow for improved circulation of the dry air.

2

EXTERNAL CONTROL OPTIONS

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Your Aprilaire dehumidifier can be controlled with an optional external control that is conveniently located in the living space. The Aprilaire
Model 76, 8620, and 8910 are recommended controls. The Model 76 is a dedicated dehumidifier control and the 8620 and 8910 integrate
dehumidification control as part of the thermostat minimizing the number of controls on the wall.

The Model 76 can also act as a remote control if the dehumidifier is located in a crawl space. Install the Model 76 in your living space and make
changes to the dehumidifier setting or find out what the humidity level is in the crawl space from the comfort and convenience of the living space.

If one of these controls or any other external control is installed, please refer to their owner’s manuals for operating instructions. Aprilaire owner’s
manuals are available at www.aprilaire.com.

If you are interested in having an external control installed, please consult your installing contractor.

Model 76 Control Model8620ThermostatorModel8910*HomeComfortControl

™

8620MainDisplayScreen 8620HumidityControlScreen

* Model 8910 consists of a thermostat and equipment control module to accommodate the installation

of various IAQ accessories.

HOW DOES THE OPTIONAL VENTILATION WORK?

If you had your contractor install the optional ventilation feature, they calculated how much fresh air was needed based on various factors
(i.e. home size, number of occupants, local building codes, etc.). Knowing how much is needed and the rate at which fresh air will be brought
into your home, the contractor set up the dehumidifier control to operate ventilation a certain amount of time per hour to provide the needed

fresh air. When ventilation operates, a damper in a duct that brings air in from the outside opens, and
your heating and cooling system blower will run to distribute the fresh air.

If you need to change the amount of time to operate ventilation, press the MODE button twice to
display the ventilation time setting. Use the UP or DOWN button to adjust the number of minutes
per hour (0–60, set to zero to turn it off) that ventilation is to run. The control will return to the
dehumidifier setting display automatically.

For additional information, go to www.aprilaire.com to find out more about the benefits of home ventilation.

MAINTENANCE

CLEAN OR REPLACE THE AIR FILTER

After initial installation the air filter should be checked and
cleaned every 6 months. The CLEAN FILTER service reminder
will display on the on-board control screen every 6 months.
To clear the service message, press the UP and DOWN
arrows simultaneously for 3 seconds.

Filter Cleaning Procedure

1. Turn the ON/OFF switch OFF.

2. Remove the filter access door from either side of the dehumidifier.

3. Slide the filter out of the dehumidifier.

4. Flush the filter with warm water and a mild detergent solution.

5. Shake off the excess water from the filter.

6. Replace the filter, making sure the filter is secured in both the top and
bottom filter rails.

7. Replace the filter access door.

8. Turn the ON/OFF switch ON.

9. Press the UP and DOWN buttons simultaneously for 3 seconds to clear
the service message.

3

MAINTENANCE (CONTINUED)

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CHECK THE DRAIN

The drain should be checked annually to ensure there are no blockages or air lock in the drain system. If the unit is not draining properly, have it
checked by a qualified service professional.

CAUTION

Do not use spray solvents or cleaners on or near the inlet side of the dehumidifier.

If desired, apply cleaner to a cloth and use to clean the cabinet.

TROUBLESHOOTING

DIAGNOSTIC CODES

The on-board control will display a diagnostic code if an error should occur and service is required.
Contact your installing contractor if E1– E7 or E9 is displayed on the on-board control screen. E8 will be
displayed if the incoming air temperature is below 50°F, above 104°F, or when the dew point is below
40°F. When the incoming air is within the acceptable range, the dehumidifier will resume operation.
If the error persists, contact your installing contractor.

LIMITED WARRANTY

Your Research Products Corporation Aprilaire® Dehumidifier is expressly warranted for five (5) years from date of installation to be free from defects in materials or workmanship.

Research Products Corporation’s exclusive obligation under this warranty shall be to supply, without charge, a replacement for any component which is found to be defective within such
five (5) year period and which is returned not later than thirty (30) days after said five (5) year period by you to either your original supplier or to Research Products Corporation, Madison,
Wisconsin 53701, together with the model number and installation date of the dehumidifier.

THIS WARRANTY SHALL NOT OBLIGATE RESEARCH PRODUCTS CORPORATION FOR ANY LABOR COSTS AND SHALL NOT APPLY TO DEFECTS IN WORKMANSHIP OR MATERIALS
FURNISHED BY YOUR INSTALLER AS CONTRASTED TO DEFECTS IN THE DEHUMIDIFIER ITSELF.

IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE SHALL BE LIMITED IN DURATION TO THE AFORESAID FIVE YEAR PERIOD. RESEARCH
PRODUCTS CORPORATION’S LIABILITY FOR INCIDENTAL OR CONSEQUENTIAL DAMAGES, OTHER THAN DAMAGES FOR PERSONAL INJURIES, RESULTING FROM ANY BREACH OF THE
AFORESAID IMPLIED WARRANTIES OR THE ABOVE LIMITED WARRANTY IS EXPRESSLY EXCLUDED. THIS LIMITED WARRANTY IS VOID IF DEFECT(S) RESULT FROM FAILURE TO HAVE
THIS UNIT INSTALLED BY A QUALIFIED HEATING AND AIR CONDITIONING CONTRACTOR. IF THE LIMITED WARRANTY IS VOID DUE TO FAILURE TO USE A QUALIFIED CONTRACTOR,
ALL DISCLAIMERS OF IMPLIED WARRANTIES SHALL BE EFFECTIVE UPON INSTALLATION.

Some states do not allow limitations on how long an implied warranty lasts or the exclusion or limitation of incidental or consequential damages so the above exclusion or limitations
may not apply to you.

This warranty gives you specific legal rights and you may also have other rights which vary from state to state.

WARRANTY REGISTRATION

Visit us on-line at www.aprilaire.com to register your Aprilaire product. If you do not have on-line access, please mail a postcard with your

name, address, phone number, email address, product purchased, model number, date of purchase and dealer name and address to:

ResearchProductsCorporation,P.O.Box1467,Madison,WI53701

YourWarrantyRegistrationinformationwillnotbesoldorsharedoutsideofthiscompany.

10011018 5.15
B2206475A

4

P.O. Box 1467 • Madison, WI 53701-1467 • Phone: [phone] • Fax: [phone] • www.aprilaire.com

Printed in U.S.A.

© 2015 Aprilaire – A division of Research Products Corporation

Model 1870 & 1870W Dehumidifier

Installation Instructions

SAFETY INSTRUCTIONS

WARNING

1. 120 Volts may cause serious injury from electric shock. Disconnect electrical power before starting installation or servicing. Leave power

disconnected until installation/service is completed.

2. Sharp edges may cause serious injury from cuts. Use care when cutting plenum openings and handling duct work.

3. Dropping may cause personal injury or equipment damage. Handle with care and follow installation instructions.

CAUTION

1. Read all instructions before beginning installation.

2. Improper installation may cause property damage or injury. Installation, service, and maintenance must be performed by a qualified service

technician.

3. Do not use in pool applications. Pool chemicals can damage the dehumidifier.

4. Do not use solvents or cleaners on or near the circuit board. Chemicals can damage circuit board components.

5. Wait 24 hours before running the unit if it was not shipped or stored in the upright position

6. Do not use dehumidification to prevent window condensation in the winter. To address window condensation, use ventilation to lower

indoor humidity in the winter.

READ AND SAVE THESE INSTRUCTIONS

English 1

TABLE OF CONTENTS

SAFETY INSTRUCTIONS � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 1

SPECIFICATIONS � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �3

SET UP DEHUMIDIFIER FOR INSTALLATION � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �3

Duct Collars� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 4
Control Location� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �5

1870W HARD WIRING� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 6
Electrical Specifications for Hard Wiring � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 6
Wiring Instructions � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �7

LOCATION CONSIDERATIONS � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 8

DRAIN INSTALLATION � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 9

Leveling � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 9
Condensate Pan, Condensate Pump and Float Switch � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 9

DUCTING TO HVAC SYSTEM – BASEMENT AND ATTIC INSTALLATIONS � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �10

DUCTING FOR STAND ALONE INSTALLATIONS OR NON-DUCTED INSTALLATIONS � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 11

DUCTING FOR TWO ZONE INSTALLATIONS � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �12

MODEL 76 – EXTERNAL CONTROL OR CRAWL SPACE/SEALED ATTIC CONTROL AND WIRING� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �13

WIRING THE DEHUMIDIFIER TO THE HVAC SYSTEM AND ZONE DAMPERS� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �14

SYSTEM SET UP AND CHECKOUT � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �15

Installer Test Mode� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 17

START UP AND SEQUENCE OF OPERATION � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �18
Single Zone Whole House or Stand Alone Using the Dehumidifier Control� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �18
Single Zone Whole House or Stand Alone Using Model 76 External Control � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �18
Crawl Space (Remote) Control Using Model 76 � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �18
Two Zone – Primary and Secondary� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �18

VENTILATION� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �19
Installation and Wiring� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �19
Vent Auto & Vent-Timed � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 20
Outdoor Temperature Sensor Installation � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 20
Determine Ventilation Requirements � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 21
Installer Settings � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 22
Sequence of Operation� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 23

TROUBLESHOOTING � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 24
TABLE 4 – Diagnostic Codes� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 24
TABLE 5 – Troubleshooting Guide� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 26

SERVICE PARTS � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 27

2 English

SPECIFICATIONS

CLIP OFF
PLASTIC

REMOVE SCREWS (2)

Model 1870 & 1870W

Weight 113 lbs�

Capacity (80°F, 60% RH Conditions) 130 pints per day @ 310 CFM

Power (115 VAC, Single Phase, 60Hz) 8�3 Amps operating current

Dehumidifier Inlet Air Conditions

Filter MERV 8, washable

External Static Pressure ("w.c.) Airflow (CFM)

Airflow

0.6" w.c. is maximum design external static pressure.

Dehumidification: 50°F – 104°F, 40°F dew point minimum

Ventilation: 40°F – 140°F, 0% RH – 99% RH (non-condensing)

0�0 310

0�2 270

0�4 225

0�6 175

The dehumidifier is not designed to prevent window condensation in winter� Indoor humidity levels must typically get lower than what dehumidifiers
can achieve to address window condensation� Use ventilation to lower indoor humidity levels in winter�

SET UP DEHUMIDIFIER FOR INSTALLATION

IMPORTANT Cut the strap securing the compressor shipping
support bracket and remove the strap and shipping bracket�
SeeFIGURE1�

FIGURE 1 – REMOVE SHIPPING BRACKET

DISCARD SHIPPING BRACKET
REINSTALL SCREWS (2)

STRAP

90-2013

English 3

DUCT COLLARS

OUTLET COVER

COLLAR W/BACK

INLET
DUCT
COLLAR

INLET
DUCT
COLLAR

TOP DISCHARGE

OUTLET COVER

STANDARD BASEMENT AND ATTIC INSTALLATIONS
(FULLYDUCTED)

• Use the screws in the parts bag to attach the duct collars to the
inlet and outlet of the dehumidifier� The outlet collar has a backflow
damper�

• The outlet duct collar may be attached to the top or end of the unit�
Move the outlet cover to the location not being used� See FIGURE 2�

• Make sure there are no bends in the ductwork coming off the outlet
for a minimum of 4”� This will ensure that the ductwork will not
interfere with the backflow damper function�

SEALED ATTIC OR BASEMENT INSTALLATIONS

FIGURE 2 – FULLY DUCTED INSTALLATIONS

OUTLET DUCT

DRAFT DAMPER

END DISCHARGE

If dehumidifying the space in which the dehumidifier is installed, the
duct collars do not need to be installed� Leave the outlet cover on top
of the unit� See FIGURE 3�

MOVE OUTLET
COVER AND
INSTALL DUCT
COLLAR TO
TOP DISCHARGE
LOCATION

90-2014

FIGURE 3 – NON-DUCTED INSTALLATIONS

90-2016

4 English

CONTROL LOCATION

PANEL COVER

CONTROL

FILTER ACCESS DOOR

The on-board control can be located on the top of the
dehumidifier or can be relocated to the front of the
dehumidifier if the control can not be seen/accessed in
the top orientation�

To move the control:

1. Remove the front control panel cover�

2. Remove the filter access door and filter�

3. Detach the on-board control by removing the four

(4) screws around the control� Note: Use one hand
to support the bottom of the on-board control
when removing�

4. Keep the control in the unit and relocate to the front
access hole�

5. Secure the control with the same four screws used
to attach the control to the top of the unit�

6. Secure the control panel cover to the top of the unit�

FIGURE 4 – CONTROL LOCATION

CONTROL

CONTROL

PANEL COVER

CONTROL

90-2017

English 5

1870W HARD WIRING

WARNING

ELECTRICAL SHOCK HAZARD: 115-volts may cause serious injury or death from electrical shock. Disconnect and tag electrical service before

starting installation or field-service. Leave electrical service disconnected until installation or field-service is complete.
ELECTRICAL SHOCK HAZARD: An interrupted or broken ground may cause property damage, serious injury or death should an electrical fault

occur. The cabinet must be grounded in accordance with NEC ANSI/NFPA 70-2011 or local codes. In Canada, refer to Canadian Electrical Code
CSA C22.1.

FIRE HAZARD: Use of improper wire may cause serious injury, property damage or death due to fire. Do not use aluminum wire for electrical
service to the dehumidifier. Use only copper wire.

CAUTION

Use of an undersized circuit breaker may cause property damage and/or the need for mold remediation service. See Specifications for wire and
circuit breaker sizing.

The Model 1870W dehumidifier must be hard wired� An electrical disconnect switch can be installed as needed to comply with appropriate codes
or ordinances� The ON/OFF switch on the dehumidifier interrupts the 115VAC service to the internal components of the dehumidifier, but does not
disconnect the power supply at the 115VAC terminals on the dehumidifier�

United States Installations: Make all electrical connections in accordance with the current edition of the NEC ANSI/NFPA 70 and any local codes or
ordinances that may apply�

Canada Installations: Make all electrical connections in accordance with the current edition of the Canadian Electrical Code CSA C22�1 and any local
codes or ordinances that may apply�

ELECTRICAL SPECIFICATIONS FOR HARD WIRING MODEL 1870W

Model 1870W

Voltage 110-120 VAC, 60 Hz, 1 phase

Minimum Circuit Capacity 12A

Maximum Fuse or Circuit Breaker Amps 20A

Minimum Wire Size AWG 14

6 English

WIRING INSTRUCTIONS

SIDE PANEL

POWER CORD

STRAIN

LINE

REQUIRED

CABLE/CONDUIT

ELECTRICAL

1. Disconnect electrical service at the main fuse or circuit breaker box�

2. Install any code required electrical disconnects to the line service�

3. Remove the side panel and electrical service panel from the
dehumidifier� See FIGURE 5�

4. Route the service cable through the 7/8" diameter hole where the

power cord was removed� USE ONLY COPPER SUPPLY WIRES�

5. Secure the cable/conduit to the dehumidifier using fittings/
connectors approved for the type of cable/conduit used�

6. Connect the ground wire of the service cable to the ground lug in
the electrical service box� See FIGURE 6�

7. Connect the line voltage wires of the service cable to the LINE BLK
and NTRL WHT terminals� See FIGURE 6�

FIGURE 5 – ELECTRICAL SERVICE BOX LOCATION

8. Reattach the electrical service panel and side panel�

9. Restore electrical service at the main fuse or circuit breaker box�

90-2018

FIGURE 6 – HARD WIRE TO 115 VAC SERVICE

VOLTAGE

USE COPPER
SUPPLY WIRES

LINE

BLK

NTRL

WHT

UTILISER DES FILS
D'ALIMENTATION
EN CUIVRE.

G

ELECTRICAL
SERVICE BOX

RELIEF

SERVICE BOX

115V AC WIRING
TERMINALS

GROUND LUG

GROUND

LINE SERVICE

NEUTRAL

FITTING AS

90-2019

English 7

LOCATION CONSIDERATIONS

FOR PROPER

ELECTRICAL SERVICE ACCESS THIS SIDE

• Allow sufficient clearance for filter removal and to
prevent airflow obstruction

• Electrical service access will require the removal
of the side panel shown� Allow sufficient space for
service on this side of the unit�

• If locating the unit in an attic or crawl space, a
Model 76 control mounted in the living space is
recommended�

• For attic installations, it is recommended that the
dehumidifier be suspended�

• Always install the dehumidifier in a condensate pan
when locating in or over a finished space�

FIGURE 7 – FILTER ACCESS CLEARANCE

6 FT. POWER CORD

TOP VIEW

FILTER

MINIMUM

20"

CLEARANCE
FOR FILTER
(EITHER SIDE)

6" MINIMUM

CLEARANCE

AIR FLOW

90-2020

8 English

DRAIN INSTALLATION

0.38

2.00

3/4 " FNPT DRAIN

The drain outlet on the dehumidifier can be hard piped using a 3/4" PVC Slip x 3/4” MNPT fitting and 3/4" nominal drain tubing or the provided 3/4”
MNPT x 3/4" hose barb fitting and 3/4" clear PVC tubing can be used to drain the dehumidifier� Always maintain a constant downward slope from the
dehumidifier to the drain and do not allow soft tubing to curl up which may result in air lock� Note: PTFE thread seal tape is recommended for the
threaded connection and hand tighten only� If hard pipe is used, PVC primer and cement is recommended for the slip fit connection�

LEVELING

The feet can be adjusted to level the unit, and if
required, to accommodate drain fittings and a
secondary condensate pan� Leveling is required
to ensure proper drainage from the dehumidifier�
See FIGURE 8�

FIGURE 8 – LEVEL THE UNIT

" MIN
" MAX

CONDENSATE PAN, CONDENSATE PUMP AND FLOAT SWITCH

Always install the dehumidifier in a condensate pan
when locating in or above a finished space� Adhere
to local codes regarding draining of the condensate
pan� If a condensate pump is needed, install it in the
condensate pan as well�

Install a condensate overflow safety switch (i�e� float
switch) in the condensate pan, remove the factory
installed jumper wire between the Float Switch
terminals on the control and wire the float switch to
the dehumidifier as shown in FIGURE 9� Overflow
safety switches on condensate pumps can be wired
to the Float Switch terminals in a similar fashion�

FIGURE 9 – FLOAT SWITCH WIRING

DH DH

FLOAT

Switch

NORMALLY CLOSED

FLOAT SWITCH

90-2020

90-2020

English 9

DUCTING TO HVAC SYSTEM – BASEMENT AND ATTIC INSTALLATIONS

SUPPLIED TO THE

DEHUMIDIFIER

10" DUCT

PLENUM BOX OR Y-FITTING

CONDENSATE PAN

PLENUM

CONDENSATE PAN

10" DIA. INSULATED DUCT

The Preferred Installation is to duct the dehumidifier to pull air from and return dehumidified air to the HVAC return duct� This installation will ensure
warm, dehumidified air is thoroughly mixed with the HVAC system air before being discharged into the living space� Alternatively, the dehumidifier
can be ducted to discharge to the supply duct, but the external static pressure of the HVAC system must not exceed 0�6” w�c�

REQUIRED COMPONENT

10" Ductwork

FIGURE 10 – PREFERRED BASEMENT INSTALLATION FIGURE 11 – ALTERNATE BASEMENT INSTALLATION

0.6" w.c .
MAX

AIR IS PULLED

FROM AND

RETURN DUCT

10" DUCT

6 ft

MIN

HVAC/FURNACE

AIR IS
PULLED FROM
RETURN DUCT

90-2022 90-2023

FIGURE 12 – PREFERRED ATTIC INSTALLATION FIGURE 13 – ALTERNATE ATTIC INSTALLATION

6" MIN.

AIR HANDLER

FILTER

10" DIA. INSULATED DUCT

BOTH SIDES

90-2024 90-2025

6 FT. MIN.

PLENUM BOX

24" MIN.

BOTH SIDES

0.6" w.c. MAX

6" MIN. 6" MIN.

AIR HANDLER

AIR IS DISCHARGED
TO SUPPLY DUCT

HVAC/ FURNACE

FILTER

DUCTING NOTES:

• Use insulated duct when the dehumidifier is located in an unconditioned space such as an attic or a garage�

• Use a minimum of 12” of flex duct at the dehumidifier inlet and outlet to prevent vibration noise transmission�

• When ducting return to return (preferred), the dehumidifier must be wired to turn on the HVAC fan when operating (see page 14)�

• When ducting return to supply, allow adequate space before the first branch duct to ensure the warm dehumidified air is thoroughly mixed with the
HVAC system air�

10 English

DUCTING FOR STAND ALONE INSTALLATIONS OR NON-DUCTED INSTALLATIONS

DEHUMIDIFIER

DEHUMIDIFIED AIR IS SUPPLIED TO DUCTED SPACE

AIR IS PULLED FROM

GRILLE WITH 10" DUCT COLLAR (2 PLACES)

In this installation the dehumidifier is not ducted to the HVAC system
and is used to dehumidify a specific area� This installation is typically in
basements or crawl spaces�

OPTIONAL COMPONENTS

10" Ductwork
Grilles with 10" Duct Collars

FIGURE 14 – STAND ALONE DUCTED

DEHUMIDIFIED SPACE

DUCTED SPACE

90-2026

10' MIN

English 11

DUCTING FOR TWO ZONE INSTALLATIONS

NORMALLY OPEN DAMPER

SECONDARY ZONE

SECONDARY ZONE

NORMALLY CLOSED DAMPER

NORMALLY CLOSED DAMPER

Note: Dehumidifier zoning is not recommended in HVAC zoning applications�

In this installation the dehumidifier controls the humidity in two separate zones, a Primary and Secondary Zone� The dehumidifier will dehumidify the
Primary Zone as the first priority, and will switch to the Secondary Zone after the dehumidification needs of the Primary Zone have been satisfied�

IMPORTANT: Normally Closed dampers must be installed in the ducts serving the Primary Zone and Normally Open dampers installed in the
ducts serving the Secondary Zone.

REQUIRED COMPONENTS

10” Ductwork and Fittings
Grilles with 10” Duct Collars
Drain Line
2 – Aprilaire Model 6510, 10” Normally Closed Damper
2 – Aprilaire Model 6610, 10” Normally Open Damper
24 VAC Transformer (40VA min�) for Dampers

Note: 5442 Basement Kit includes 2 – 6510 Dampers, 2 – 6610 Dampers, and a 24VAC (40VA) transformer

FIGURE 15 – WHOLE-HOME PRIMARY ZONE INSTALLATION

NORMALLY

CLOSED

DAMPERS

RETURN FROM

FIGURE 16 – WHOLE-HOME SECONDARY ZONE INSTALLATION

TO/ FROM

PRIMARY ZONE

RETURN

DUCT

6 ft
MIN

NORMALLY OPEN DAMPER

TO/ FROM

SECONDARY ZONE

RETURN

DUCT

SUPPLY DUCT

SUPPLY TO

90-2027

SUPPLY DUCT

NORMALLY
OPEN
DAMPER

12 English

RETURN FROM

PRIMARY ZONE

NORMALLY

OPEN

DAMPER

SUPPLY TO

PRIMARY ZONE

90-2028

MODEL 76 – EXTERNAL CONTROL OR CRAWL SPACE/SEALED ATTIC CONTROL AND WIRING

NO/NC SWITCH

Note: Use 18-22 AWG wire for control wiring�

FIGURE 17 – MODEL 76 EXTERNAL CONTROL WIRING

EXTERNAL CONTROL

Used as an external control, the Model 76 is
mounted in the space that is to be dehumidified�
When the dehumidifier is powered, the display on
the dehumidifier control will show “EXTERNAL”
to indicate that an external control is being used�
External controls are recommended when the
dehumidifier is installed in an attic and is ducted to
the HVAC system�

The Model 76 uses a normally open (NO), dry
contact (i�e� not a triac or other semiconductor)
relay to complete the circuit between the DH
terminals of the dehumidifier control� If using other
controls such as a thermostat with dehumidification
outputs, ensure the output is a dry contact type
and set the NO/NC switch on the dehumidifier
control (see FIGURE 17) to correspond with the
control being used� The Aprilaire Model 8620
Thermostat or Model 8910 Home Comfort Control
are recommended alternate controls and both use
normally open contacts�

If an external control is used in a zoned application,
it must be located in the Primary Zone (refer to
TWO ZONE – PRIMARY AND SECONDARY on page
18 for details)�

NC NO

FIGURE 18 – MODEL 76 CRAWL SPACE/SEALED ATTIC (REMOTE) WIRING

+ - A B ODT

DH DH

Switch

FLOAT

VENT DEH

Dampers

SensorRemote

Gh Rf Cf Gs YW

HVAC EQUIP.

MODEL 76 CONTROL

A

B
C/­R/+

DH
DH

90-1862

CRAWL SPACE/SEALED ATTIC CONTROL

Used as crawl space or sealed attic control (or
remote control), the Model 76 is mounted in the
living space while the dehumidifier is located in the
area to be dehumidified� When the dehumidifier is
powered, the display on the dehumidifier control
will show “REMOTE” to indicate that a remote
control is being used� The RH shown on the Model
76 is the RH measured at the dehumidifier�

Remote control is typically used for crawl space or
sealed attic applications, but is also recommended
when the dehumidifier and the space being
dehumidified are inconvenient or difficult for
the homeowner to access� Examples of this type
of application include basements that may be
inconvenient to access or storage areas�

+ - A B ODT

SensorRemote

Gh Rf Cf Gs YW

HVAC EQUIP.

MODEL 76 CONTROL

R/+

A
B

C/-

DH
DH

90-1860

English 13

WIRING THE DEHUMIDIFIER TO THE HVAC SYSTEM AND ZONE DAMPERS

NORMALLY CLOSED

NORMALLY OPEN

Note: Use 18-22 AWG wire for wiring to HVAC system and zone
dampers�

Pull off the wiring access cover near the dehumidifier control to access
the wiring terminals� Snap the wiring access cover back into place after
completing all wiring�

FIGURE 19 – WIRING TO HVAC SYSTEM

WIRING TO THE HVAC SYSTEM

When the dehumidifier is ducted to the HVAC system, it is
recommended that it also be wired to the HVAC system as shown
in FIGURE 19� If ducted to the HVAC system in return to return
configuration, the dehumidifier must be wired to the HVAC system
to prevent short circuiting dehumidified air directly back to the
dehumidifier inlet� In return to supply ducting configuration, running
the HVAC fan with the dehumidifier ensures the warm dry air is mixed
with room air before being discharged to the home�

OPTIONAL W & Y WIRING

Wire the W and/or Y terminal to the HVAC system when using the
ventilation feature of the dehumidifier (see VENTILATION on page 19)�

Wire the dehumidifier Y terminal to the HVAC system if it is desired
to disable the dehumidifier compressor from operating when the air
conditioning is running� See DEH W/AC in SYSTEM SET-UP on page 16
for additional set up steps required to access this feature�

WIRING TO ZONE DAMPERS

FIGURE 20 – TWO ZONE WIRING ON-BOARD CONTROL

THERMOSTAT

OR ZONE

CONTROL BOARD

R
C
G

W

Y

+ - A B ODT VENT DEH

DH DH

FLOAT

EXISTING WIRE
NEW WIRE

HVAC

EQUIPMENT

G
R
C

W

Y

Sensor DampersRemote

Switch

HVAC EQUIP.

Gh Rf Cf Gs YW

OPTIONAL

WIRES

90-1859

14 English

+ - A B ODT VENT

DH DH

FLOAT

Sensor DampersRemote

Switch

(40 VA min)

DEH

24 VAC

Gh Rf Cf Gs YW

HVAC EQUIP.

Note: Dehumidifier zoning
is not recommended in
HVAC zoning applications�

(PRIMARY ZONE)

(SECONDARY ZONE)

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SYSTEM SET-UP & CHECKOUT

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90-1854

90-1854

90-1854

If dehumidifier installation does not include ventilation or zoning and
will not be wired to an external control, remote control or the HVAC
system, proceed to Installer Test Mode section on page 17�

1. Check all wiring�

2. Make sure the wire access cover has been snapped back onto the

on-board control�

3. Plug unit in and turn power switch to ON�

4. The on-board control screen should display OFF�

Note: If the display backlight is not on, the first button press (any

button) will only turn on the backlight� Press the button a second time
to achieve function�

5. Hold the MODE button on the on-board control for 3 seconds to
enter the Installer Set-up Menu�

6. Navigate through the following screens to set up the dehumidifier
for the installed application�

Use the

or buttons to select items and use MODE to
switch to the next set-up option� To exit installer set-up, all options
must be scrolled through using the MODE button�

7. After the installer set up options have been completed, DONE will
blink for 3 seconds and the control will return to the OFF screen�

VENTILATION

If not using the dehumidifier to
bring in outdoor air, press MODE
to go to ZONE screen selections�

If using the dehumidifier for
ventilation, Enable and press
MODE to select TIMED or AUTO�

If ventilating based on time
only (no outdoor temperature
restrictions), press MODE at the
VENT TIMED screen to go to
ventilation time selection screen�

If ventilating with outdoor temperature restrictions, use the

button
to go from VENT TIMED to VENT AUTO –B and then the or
buttons to select the desired ventilation mode, B, C, or D� Press MODE
to go to the ventilation time selection screen�

Vent-Auto-B: Ventilation
prevented when outdoor
temperature is below 0°F and
above 100°F� Between 0°F – 20°F
ventilation is only allowed during
a HVAC heat call�

REMOTE CONTROL – CRAWL SPACE/SEALED ATTIC

If not installing in a crawl space or
sealed attic with Model 76 remote
control, press MODE to go to
VENT screen selections

If installing in a crawl space or
sealed attic with remote control,
Enable and press MODE� The
installer set-up is complete,
proceed to Installer Test Mode
section on page 17�

Vent-Auto-C: Ventilation
prevented when outdoor
temperature is below 0°F and
above 100°F�

Vent-Auto-D: Ventilation
prevented when outdoor
temperature is below 0°F and
above 90°F� Between 0°F – 40°F
ventilation is only allowed during
a HVAC heat call�

Vent-Auto-B, -C, -D modes apply outdoor temperature limits and
require an outdoor temperature sensor to be installed�

Press the or buttons to
adjust the ventilation time per
hour from 0 to 60 minutes� After
selecting time, press MODE to go
to the ZONE screen selections�

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ZONE

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DEH W/AC

EXTERNAL CONTROL

If installing the dehumidifier in
a single zone application, select
DISABLED and press MODE to go
to the EXTERNAL control screen
selections�

If installing the dehumidifier in
a two-zone application, use the

or buttons to select
ENABLED and press MODE to go
to the EXTERNAL control screen
selections�

If using the dehumidifier
on-board control select DISABLED
and press MODE to go to
the dehumidification with air
conditioning (DEH W/AC) screen
selections�

If using a Model 76, Model 8910,
or Model 8620 as an external
control or other third-party
external control, such as a
thermostat with dehumidifier
outputs, use the or
buttons to select ENABLED
and press MODE to go to
the dehumidification with air
conditioning (DEH W/AC) screen
selections�

To allow dehumidification during
active air conditioning, select
ENABLED and press MODE�

To disable dehumidification when
the air conditioning is on, select
DISABLED and press MODE�

RH OFFSET

An offset can be applied to the
on-board humidity reading to
avoid discrepancies with other
humidity measuring devices in
the home� Use the or
buttons to select an offset from

-5% to 5%� Press MODE to exit
the installer set-up screens�

16 English

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INSTALLER TEST MODE

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90-1854

If everything is properly wired, the dehumidifier and all of the wired components will turn on and off during Installer Test Mode to demonstrate that
all are properly operating� Installer Test Mode lasts for four (4) minutes� If the ON/OFF button is pressed during test mode, the dehumidifier will exit
Installer Test Mode and return to the OFF screen�

DEHUMIDIFICATION ONLY

If the dehumidifier is not already
OFF, press the ON/OFF button to
turn it off�

Press and hold the ON/OFF and
MODE buttons for 3 seconds�
The measured humidity, AIR
SAMPLING and TEST will show
on the display� If wired to the
HVAC system, the HVAC blower
will turn on and if there is/are
damper(s) wired to the DEH
DAMPER terminals of the control,
the damper(s) will energize�

After three (3) minutes the
dehumidifier compressor will
turn on and DEHUMIDIFYING will
replace AIR SAMPLING on the
control screen�

ZONING AND/OR VENTILATION

If the dehumidifier has been set
up for ventilation, VENTILATING
will appear on the display
throughout Installer Test Mode,
and the ventilation damper will be
energized�

If the dehumidifier has been set
up for zoning, PRIMARY ZONE will
show on the display for the first
minute of dehumidifier blower
operation� After one minute,
SECONDARY ZONE will show on
the display and the zone dampers
will de-energize�

After one minute of compressor
operation, all outputs will turn off
and DONE will blink for 3 seconds
and then return to the OFF screen�

English 17

START UP AND SEQUENCE OF OPERATION

SINGLE ZONE WHOLE HOUSE OR STAND ALONE USING
THE DEHUMIDIFIER CONTROL

1. Press the ON/OFF button to turn the dehumidifier control ON� The

display will show the current setting, and the dehumidifier blower
and HVAC blower (if wired to the HVAC system) will turn on to
start sampling the air�

The setting will be replaced by the measured humidity and “AIR

SAMPLING” will show on the display�

2. Use the
desired� The recommended initial setting is 59%�

3. After three (3) minutes of sampling, the measured humidity will be
compared to the setting:

a. If the humidity is above the setting, the dehumidifier

b. If the measured humidity is below the setting, the blowers turn

4. The dehumidifier will sample again every 60 minutes, or at any

time if the humidity setting is lowered�

or button to adjust the humidity setting as

compressor turns on and “AIR SAMPLING” will be replaced
by “DEHUMIDIFYING”� The compressor remains on until the
measured humidity falls 3% RH below the setting�

off and the display returns to showing the RH setting�

CRAWL SPACE OR SEALED ATTIC (REMOTE) CONTROL USING
MODEL 76

1. Press the ON/OFF button to turn the dehumidifier control ON�

“REMOTE” will show on the display to indicate that a remote
control is wired to the dehumidifier�

2. At the Model 76, press the ON button; the Model 76 will display the
RH measured at the dehumidifier, and the dehumidifier blower will
turn on to start sampling the air�

3. Use the
level as desired� The dryness levels are from 1 to 7, with 1 being
least dry and 7 being most dry; the recommended initial setting
is3�

4. After three (3) minutes of sampling, the measured humidity will be
compared to the setting:

a. If the humidity is above the setting, the dehumidifier

b. If the measured humidity is below the setting, the dehumidifier

5. The dehumidifier will sample again every 60 minutes, or at any

time if the dryness level is increased�

or button on the Model 76 to adjust the dryness

compressor turns on and “ON” flashes on the Model 76 display�

blower turns off�

SINGLE ZONE WHOLE HOUSE OR STAND ALONE USING MODEL
76 EXTERNAL CONTROL

1. Press the ON/OFF button to turn the dehumidifier control ON�

“EXTERNAL” will show on the display to indicate that an external
control is wired to the dehumidifier�

2. At the Model 76, press the ON button; the Model 76 will display the
measured RH�

3. Use the
setting as desired� The recommended initial setting is 59%�

4. If the RH measured by the Model 76 rises above the setting,
the dehumidifier will turn on as will the HVAC blower (if wired
to the HVAC system)� “DEHUMIDIFYING” will appear on the
dehumidifier control display to show that the Model 76 is calling
for dehumidification� The dehumidifier and HVAC blower (if on)
will turn off when the RH measured by the Model 76 drops 3% RH
below the setting�

or button on the Model 76 to adjust the humidity

TWO ZONE – PRIMARY AND SECONDARY

1. Press the ON/OFF button to turn the dehumidifier control ON�

Dehumidification of the Primary Zone follows the same sequence

as described to the left for Single Zone, with or without a Model
76 external control installed in the Primary Zone� The dehumidifier
control display will show “PRIMARY ZONE” in addition to that
described to the left when sampling or dehumidifying the
Primary Zone� The zone dampers are energized when sampling or
dehumidifying the Primary Zone�

2. The Secondary Zone uses the humidity setting on the dehumidifier
control� During Secondary Zone sampling or dehumidification, the
zone dampers are de-energized and the HVAC blower (if on) stops�
“SECONDARY ZONE” will show on the dehumidifier control display
when the Secondary Zone is either sampling or dehumidifying� If
the Primary Zone had just finished a dehumidification demand, the
compressor will continue to run during Secondary Zone sampling
to prevent short cycling of the compressor�

The Secondary Zone is sampled immediately after the Primary

Zone has finished sampling, or if there is a call for dehumidification
from the Primary Zone, immediately after the call has been
satisfied� When a Model 76 external control is installed, the
Secondary Zone will be sampled once per hour if there has not
been a call for dehumidification from the Primary Zone� Secondary
Zone sampling will also occur whenever the setting on the
dehumidifier control is lowered�

18 English

VENTILATION

DAMPERS

NORMALLY CLOSED

THERMOSTAT

TEMPERATURE SENSOR

NORMALLY CLOSED

FURNACE

The dehumidifier can activate a normally closed damper to bring in outdoor air through a fresh air intake duct� This feature cannot be used when a
Model 76 has been installed in a Remote Control application, and is not recommended when using primary and secondary zoned dehumidification�

REQUIRED COMPONENTS

Aprilaire Model 6506, Normally Closed Damper
6” Insulated Duct for Fresh Air Intake Duct
24 VAC Transformer (10VA min�) for Ventilation Damper
Intake Hood
18-22 AWG Wire

INSTALLATION & WIRING

FIGURE 21 – SINGLE ZONE, ON-BOARD CONTROL

VENTILATION INSTALLATION

AIR IS PULLED

FROM OUTSIDE

VENT DAMPER

BALANCING

6 ft
MIN

HVAC/ FURNACE

90-2029

OPTIONAL COMPONENTS

8052 Outdoor Temperature Sensor

FIGURE 22 – SINGLE ZONE, EXTERNAL CONTROL
VENTILATION INSTALLATION

AIR IS PULLED

FROM OUTSIDE

VENT DAMPER

6 ft
MIN

HVAC/

90-2030

FIGURE 23 – VENTILATION WIRING

+ - A B ODT VENT DEH

DH DH

FLOAT

Switch

OPTIONAL OUTDOOR

(Model 8052)

6" NORMALLY

CLOSED DAMPER

24 VAC

(10 VA min)

TRANSFORMER

Sensor DampersRemote

Gh Rf Cf Gs YW

HVAC EQUIP.

HVAC

EQUIPMENT

Y

W

C
R
G

Y
W
G
C
R

OR ZONE

CONTROL

BOARD

90-1861

English 19

VENT-AUTO & VENT-TIMED

TEMPERATURE

TEMPERATURE SENSOR

CENTER LINE

The dehumidifier can ventilate in four modes.

Vent-Timed: Ventilation occurs based only on time setting; no temperature restrictions�

Vent-Auto-B: Ventilation prevented when outdoor temperature is below 0°F and above 100°F� Between 0°F – 20°F ventilation is only allowed during

a HVAC heat call�

Vent-Auto-C: Ventilation prevented when outdoor temperature is below 0°F and above 100°F�

Vent-Auto-D: Ventilation prevented when outdoor temperature is below 0°F and above 90°F� Between 0°F – 40°F ventilation is only allowed during

a HVAC heat call�

Vent-Auto-B, -C, -D modes apply outdoor temperature limits and require an outdoor temperature sensor to be installed�

OUTDOOR TEMPERATURE SENSOR INSTALLATION

The Outdoor Temperature Sensor should be installed outside in a shaded location, or in the outdoor air intake duct�

FIGURE 24 – ODT MOUNTED OUTSIDE FIGURE 25 – ODT MOUNTED IN INTAKE DUCT

OUTDOOR

LEADS

NORTH, EAST
OR WEST SIDE
OF HOME

ABOVE EXPECTED

SNOW LINE

SENSOR
BRACKET

OUTDOOR

SENSOR

SENSOR

36" MAX.

OUTSIDE WALL

B2202617-D B2202617-E

20 English

DETERMINE VENTILATION REQUIREMENTS

CALCULATING AIRFLOW REQUIREMENT

1. The MINIMUM ventilation requirement is calculated using ASHRAE

62�2-2010�

TABLE 1 – CFM REQUIRED

Number of Bedrooms

House Sq. Ft.

2 3 4 5 6

ASHRAE Airflow in CFM = [House Area in Sq� Ft� x 0�01] +

[(Number of Bedrooms +1) x 7�5]

Note: Use ‘Number of Bedrooms + 1’ or ‘Number of Occupants’,

whichever is larger�

2. TABLE 1 shows the calculated airflow values to the nearest 5 CFM�

3. Record the required CFM� ________

1000 35 40 50

1500 40 45 55 60 70

2000 45 50 60 65 75

2500 50 55 65 70 80

3000 55 60 70 75 85

3500 75 80 90

DETERMINE FRESH AIR DELIVERY RATE

1. Measure the negative static pressure of the return system at the location where the fresh air intake duct enters the return duct or dehumidifier inlet�

2. See TABLE 2 for estimated inlet airflow in CFM, based on duct type, length and available negative pressure� Use an airflow measuring device for a

more accurate airflow delivery rate�

3. Record the delivered CFM� ________

TABLE 2 – CFM DELIVERED

Negative Static Pressure (“w.c.) as Measured for Return Duct or Plenum

Duct Length

10 ft. 60 65 85 90 105 110 120 125 135 140 150 160

20 ft. 55 60 80 85 100 105 115 120 130 135 140 150

30 ft. 50 55 75 80 95 100 110 115 125 130 130 140

0.05 0.1 0.15 0.2 0.25 0.3

Flex Pipe Flex Pipe Flex Pipe Flex Pipe Flex Pipe Flex Pipe

Note: For the table above, 6” flex duct is laid loose with two, wide 90° bends and a fully opened damper� Rigid pipe values are based on 6” duct, two
90° elbows, and a fully open damper� In both cases, the air intake is through a metal vent hood with inlet screen� Airflow may need to be adjusted up
or down for variations in duct work�

DETERMINE CYCLE TIME

1. Use the Required CFM and Delivered CFM from the above steps to determine the Cycle Time from TABLE 3�

2. The values highlighted in gray cannot be set due to the maximum 60 minute Cycle Time� A second ventilation device (i�e�, bigger duct or second

duct) will be required to meet ventilation needs�

English 21

TABLE 3 – CYCLE TIME SETTING (MINUTES) FOR AIRFLOW DELIVERED VS. AIRFLOW REQUIRED FOR 1 HOUR CYCLE

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CFM Delivered

60 20 30 40 50 60 70 80 90 100

80 15 25 30 40 45 55 60 70 75

100 15 20 25 30 35 40 50 55 60

120 10 15 20 25 30 35 40 45 50

140 10 15 15 20 25 30 35 40 45

160 10 10 15 20 25 25 30 35 40

INSTALLER SETTINGS

CFM Required

20 30 40 50 60 70 80 90 100

With the dehumidifier power
switch on, press the ON/OFF
button to turn the dehumidifier
off�

Press the or button to
toggle between VENT TIMED,
VENT AUTO-B, VENT AUTO-C and
VENT AUTO-D (refer to page 20
for a description of each)� Press
the MODE button to select the

Press and hold the MODE button
for 3 seconds to access the
installer settings menu� Press
and release the MODE button
repeatedly until the VENT
DISABLED screen appears�

desired ventilation method and
adjust the ventilation time�

Press the or button
to set the desired amount of
ventilation time per hour from
0to60 minutes�

Press the or button to
ENABLE ventilation, then press
the MODE button to set Timed or
Auto ventilation�

To complete, press the MODE
button repeatedly until DONE
appears on the display�

22 English

SEQUENCE OF OPERATION

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When wired as shown in FIGURE 23, the ventilation damper will open whenever there is an HVAC heating (W), cooling (Y) or fan (Gs) call, allowing
fresh air to be brought in when the HVAC blower is running (see VENTILATION WITH AN EXTERNAL CONTROL section below for exceptions)� The
ventilation damper will also open if the dehumidifier is operating� “VENTILATING” will show on the dehumidifier control when the dehumidifier
is actively ventilating� When the HVAC call ends, the dehumidifier stops, or after the set amount of ventilation time has been met, the ventilation
damper will be closed�

If the set amount of ventilation time has not been met before the end of the one-hour cycle, the dehumidifier will turn on the ventilation damper
along with the HVAC blower to ensure the desired ventilation time is satisfied�

If the dehumidifier has been set up to operate ventilation with outdoor temperature restrictions (AUTO-B, AUTO-C or AUTO-D – refer to page 20)
then ventilation will be limited as described�

DEHUMIDIFYING THE FRESH AIR

When the dehumidifier is set up for single zone and there is no external control installed, the dehumidifier will turn on its blower and measure
the RH of the air entering the dehumidifier during ventilation when ducted as shown in FIGURE 21� If the relative humidity of the air entering the
dehumidifier is higher than the setting, the dehumidifier compressor will turn to remove moisture�

VENTILATION WITH AN EXTERNAL CONTROL

When an external control is installed the dehumidifier will open the ventilation damper only when there is a cooling call (Y) or when the dehumidifier
is operating, unless the ventilation need has not been met� If the set amount of ventilation time has not been met before the end of the one-hour
cycle, the dehumidifier will turn on the ventilation damper along with the HVAC blower to ensure the desired ventilation time is satisfied�

ADJUSTING VENTILATION TIME AFTER INITIAL SET UP

1. Press the or button to access the RH adjustment screen or to turn on the backlight if using an

External Control�

2. Press the MODE button to toggle to the VENT TIME setting�

3. Press the or button to adjust the ventilation time (minutes)� After adjusted, press nothing else; the

screen will return to home screen after three (3) seconds�

English 23

TROUBLESHOOTING

90-1854

Technical Support is available Monday through Friday, 7:00 a�m� to 5:00 p�m� CST, at [phone]� Use the guides on the following pages to identify
and correct system faults� Contact Technical Support before replacing the unit or any components and for additional troubleshooting�

DIAGNOSTIC CODES

When an error occurs, the Diagnostic Code along with SERVICE REQUIRED
will be displayed on the control screen�

TABLE 4 – DIAGNOSTIC CODES

Diagnostic

Code Failure Mode Action Reset

E1 Internal Humidity or

Temperature Sensor
Open or Shorted

E2 High Refrigeration

Pressure

E3 Model 76 Remote

Control Communication
Loss

E4 Insufficient Capacity 1. Check the frost sensor connection at the power board� Terminal should be fully seated on the

1. Check the connection between the sensor board and control board�

2. If connection okay, replace sensor board, Part No� 5460�

1. Verify that the fan works, the backflow damper swings freely and there is no blocked or restricted

ductwork�

2. If the fault persists, call Technical Support�

1. Check connections between Model 76 and dehumidifier control board� Terminals should be fully

inserted and secured in the control board and Model 76 control terminals�

2. If connections are correct and secure, turn off the dehumidifier and remove the Model 76�
Use a short section of 4-wire cable to reconnect the Model 76 to the control board� Turn the
dehumidifier back on and increase the dryness level setting on the Model 76� If the dehumidifier
turns on, the problem is with the wiring between the dehumidifier and control�

3. If the dehumidifier does not turn on, call Technical Support�

power board pins�

2. Remove the side access panel and verify that the sensor is secured to the suction line�

3. If the sensor is connected and secured to the refrigeration line proceed to the next step�

4. Reset the fault by cycling power to the dehumidifier�

5. Turn the humidity setting down (below room/home humidity level) to make a dehumidification

call�

6. Allow the fan and compressor to run for approximately 10-15 minutes and then enter diagnostic
test mode by simultaneously pressing the
display the temperature measured by the internal sensor while also displaying AIR SAMPLING
and ON, the humidity measured by the internal sensor while also displaying %RH and ON, and
the frost sensor temperature while also displaying ON� Scroll through these values by using the

or buttons�

7. Record values and call Technical Support�

and MODE buttons for 3 seconds� The LCD will

Cycle Power

Cycle Power

Self-Correcting

Cycle Power

E5 High Temperature

Thermistor Failure

E6 Low Temperature

Thermistor Failure

24 English

1. Check the high temperature sensor connection at the power board� Terminal should be fully
seated on the power board pins�

2. Remove the side access panel and verify the sensor is not damaged and connected to the
refrigeration line coming from the compressor�

3. If the sensor is connected and secured to the refrigeration line, it may need to be replaced with
Part No� 5456 – contact Technical Support to confirm�

1. Check the low temperature sensor connection at the power board�

2. Remove the side access panel and verify the sensor is not damaged and connected to the suction

line�

3. If the sensor is connected and secured to the refrigeration line, it may need to be replaced with
Part No� 5455 – contact Technical Support to confirm�

Cycle Power

Cycle Power

TABLE 4 – DIAGNOSTIC CODES

Diagnostic

Code Failure Mode Action Reset

E7 Float Switch Open 1. Empty the condensate pan�

2. Check the float switch connection at the control board�

3. If not using a float switch, verify jumper is between float switch terminals on dehumidifier control

board�

4. If the problem persists, replace the float switch�

E8 Inlet Air Temperature

Out of 50°F – 104°F
range or dew point

1. Verify all ductwork is properly sealed�

2. If no signs of leak points, contact Technical Support�

below 40°F

E9 Outdoor Temperature

Sensor Open or Shorted

1. Check the sensor connection at the power board�

2. Remove the wires from the terminals and

measure the resistance� A short circuit will have
a resistance very close to 0 Ohms and an open
circuit will have a very high resistance� The table
at right can be used to approximate the resistance
based on outdoor temperature�

3. If the sensor is not reading correctly, replace the
sensor, Part No� 8052�

Outdoor

Temperature Resistance

0°F 84,500 Ohms

20°F 46,000 Ohms

40°F 26,000 Ohms

60°F 15,500 Ohms

80°F 9,500 Ohms

100°F 6,000 Ohms

Self-Correcting

Self-Correcting

Self-Correcting

English 25

TABLE 5 – TROUBLESHOOTING GUIDE

Symptom Possible Reason Troubleshooting Procedure

Dehumidifier does not
turn on/run�

Dehumidifier blower is
running but with little or
no airflow�

Dehumidifier blower is
running but compressor
is not�

When zoned, the
dehumidifier damper
does not open in
INSTALLER TEST mode�

No power to unit� • Check that the dehumidifier is plugged in�

• Check that the power switch is turned ON�

• Check that the control is turned ON�

• Check that the circuit breaker has not tripped�

Pressure drop across
dehumidifier is higher
than 0�6”w�c�

• Check dehumidifier air filter and wash or replace�

• Check for blocked duct work and clear�

• Verify that the outlet collar with backflow damper is installed on the outlet side of the dehumidifier�

• Check if backflow damper is blocked or stuck and remove obstruction�

Float switch open� • If float switch installed, check connections at control board and empty condensate pan�

• If no float switch installed check that the jumper is installed at the float switch terminals on the control
board�

Coil frosting�
DEFROSTING will be
displayed on control
screen�

Inlet air temperature is

• Lack of or reduced airflow� Check dehumidifier air filter and wash or replace�

• Check for blocked duct work�

• Inlet air conditions below 60°F� Increase the humidity setting�

• Verify all ductwork is properly sealed�

outside of the 50°F –
104°F range or the dew
point is below 40°F and
there is a demand for
dehumidification�

Incorrect damper wiring
or bad connection�

• Verify wiring between dampers and 24 VAC transformer�

• If wired for Two Zone operation, verify that 24 VAC transformer is 40 VA minimum�

• Check all wiring connections between dampers and control board�

• Verify the normally closed dampers are in the Primary Zone ductwork and the normally open dampers
are in the Secondary Zone ductwork�

The ventilation damper
does not open when the
HVAC fan is active�

Dehumidifier is not
draining properly�

The HVAC fan turns on
unexpectedly�

Dehumidifier is
producing hot air�

Cycle time has been

• The damper will not open if the Ventilation Time has already been met�

met�

ODT error or outdoor air
outside of ODT range�

• Check that the ODT is wired correctly to the
dehumidifier control board and connections are
secure�

• Check that the ODT is installed in the outdoor air

Outdoor

Temperature Resistance

0°F 84,500 Ohms
intake according to the set-up specified in the
Ventilation Section beginning on page 19�

• Remove the ODT leads from the dehumidifier control
board and check the resistance� Compare the reading
with the table shown�

20°F 46,000 Ohms

40°F 26,000 Ohms

60°F 15,500 Ohms

80°F 9,500 Ohms

100°F 6,000 Ohms

Drain line blocked or unit
not level�

Dehumidifier is sampling
or ventilation in

• Verify that the unit is level�

• Check the drain line blockages and for a continuous downward slope�

• The dehumidifier will turn on the HVAC fan during air sampling or as needed to meet the ventilation
time�

progress�

Normal function� • Air is reheated across the condenser coil, resulting in a temperature rise between inlet and outlet�

26 English

SERVICE PARTS

4

5

9

18

3

10

20

1

7

11

13

14

2

16

6

No. Part Description Part No.

1 Filter, 14” x 19” x 1” EZK 5569

2 Internal Control Board, Deh 5444

3 User Interface Assembly, Deh 5445

4 Wiring Access Door, AA Deh 5446

5 Hole Cover, UI Ctrl, Deh 5447

6 Door, Filter Access, AA Deh 5571

7 Outlet Duct Panel, Deh 5449

8 Backflow Damper, 10”, Deh 5450

9 Inlet Duct Panel, AA Deh 5451

10 Cover, Outlet, AA Deh 5452

17

15

8

12

19

No. Part Description Part No.

11 Fan, 130pt Deh, with 10MFD Capacitor 5572

12 Wire Harness, Power, Deh 5454

13 Sensor, Low Temperature, Deh 5455

14 Sensor, High Temperature, Deh 5456

15 Leveling Foot, Deh 5457

16 Capacitor, 50MFD, 370VAC 5594

17 Capacitor, 10MFD, 250VAC 5573

18 RH Sensor, Deh 5460

19 Drain Tube + Fitting 5665

20 Compressor Overload Switch 5574

90-2031

English 27

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