Aprilaire 8840 Setup guide

Thermostat
SAFETY & INSTALLATION
INSTRUCTIONS
Model 8840
Touch Screen Wi-Fi Automation
Thermostat with Integrated
Indoor Air Quality Solutions
TABLE OF CONTENTS
INSTALLATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Thermostat Location
Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . 2
Thermostat Mounting . . . . . . . . . . . . . . . . . . . . . . 2
Equipment Control Module Location
Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . 2
Equipment Control Module Mounting . . . . . 3
Thermostat Wiring. . . . . . . . . . . . . . . . . . . . . . . . . . 3
Remote Temperature Sensor
(Optional) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Support Module Wiring (Optional). . . . . . . . . 4
Equipment Control Module Wiring. . . . . . . . . 5
Outdoor Temperature Sensor
(Included) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Optional Wireless Outdoor
Temperature and Humidity Sensor . . . . . . . 6
Return Air Temperature Sensor
(Optional) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Leaving Air Temperature Sensor
(Optional) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
HVAC WIRING DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . 8
Conventional Heat/Cool
Single Transformer. . . . . . . . . . . . . . . . . . . . . . . . . . 8
Conventional Heat/Cool
Two Transformer . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Heat Pump Single Transformer . . . . . . . . . . . . 9
Heat Pump Two Transformer. . . . . . . . . . . . . . . 9
INDOOR AIR QUALITY WIRING DIAGRAMS . . . . 10
Indoor Air Quality Wiring with
Separate Transformers. . . . . . . . . . . . . . . . . . . . 10
Indoor Air Quality Wiring with
a Single Transformer . . . . . . . . . . . . . . . . . . . . . . 10
POWER & RESET OPTIONS . . . . . . . . . . . . . . . . . . . . . . 11
SETUP & TESTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Installer Setup Wizard . . . . . . . . . . . . . . . . . . . . . . 11
HVAC Installer System Settings Tables . . . . 11
General System Settings. . . . . . . . . . . . . . . . 11
Thermostat System Settings . . . . . . . 12-14
Indoor Air Quality System
Settings Tables. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
 HumidierSystemSettings . . . . . . . . . 14-15
 DehumidierSystemSettings . . . . . . . . . 16
Air Cleaning System Settings. . . . . . . . . . 16
Fresh Air System Settings . . . . . . . . . . . 17-18
Installer System Test. . . . . . . . . . . . . . . . . . . . . . . 18
WiFi Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
QUICK REFERENCE TO CONTROLS
& DISPLAY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
THERMOSTAT FEATURES . . . . . . . . . . . . . . . . . . . . . . . 22
TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . .23
SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Product Info &
Digital Manual

INSTALLATION
THERMOSTAT LOCATION RECOMMENDATIONS
Thermostat should be mounted:
• On an interior wall, in a frequently occupied space.
• Approximately5feetaboveoor.
• At least 18” from outside wall.
• Thermostat can be mounted to a vertical junction box.
Do not mount thermostat:
• Behind doors, in corners or other dead air spaces.
• Indirectsunlight,nearlightingxtures,orotherappliancesthatgiveoffheat.
• On an outside or unconditioned area wall.
• Intheowofasupplyregister,instairwells,ornearoutsidedoors.
• On a wall with concealed pipes or ductwork.
THERMOSTAT MOUNTING
1. Remove the rear mounting plate from
the thermostat.
2. Pull wires through the opening on the
rear mounting plate.
3. Position and level the mounting plate
of the thermostat on wall and mark the
hole locations with a pencil.
4. Drill 1/4” holes and insert supplied
anchors (drywall only).
5. Place mounting plate over anchors,
insert and tighten screws.
6. Seal wire entry holes to prevent drafts
affecting temperature readings.
EQUIPMENT CONTROL MODULE LOCATION RECOMMENDATIONS
NOTE: Installer must touch a grounded metal object before handling the equipment control
module to avoid potential damage due to electrical discharge.
Equipment control module should be mounted:
• In a location where the temperature will not exceed 158°F (70°C) or drop below 32°F (0°C).
Do not mount equipment control module:
• On foundation walls or on the HVAC equipment or ductwork. These locations can cause
moisture to condense on the equipment control module.
90-2122
FIGURE 1
FIGURE 2
FIGURE 4 – THERMOSTAT WIRING
FIGURE 3
EQUIPMENT CONTROL MODULE
MOUNTING
The equipment control module has the
following features to simplify mounting
and wiring and provide for a clean and
neat installation.
• Six (6) mounting holes. One on each
corner and two centered top and
bottom. Any combination of these holes
may be utilized. Mount the equipment
control module using 2 to 4 #8 screws
appropriate for the mounting surface
substrate. (See FIGURE 3.)
• Wires can be routed through the top,
bottom, sides or back.
• Nylon wire ties can be used to secure
wires in 10 places.
Installation steps:
1. Select mounting location.
2. Pull from bottom to remove front cover.
(See FIGURE 2.)
3. Mount base using 2 to 4 #8 screws
(eldsupplied).
THERMOSTAT WIRING
Wire specications:
• 18-24 gauge thermostat wire
Installation notes:
• Ensure power at the HVAC equipment
is off.
• Loosen screw terminals, insert stripped
wire and re-tighten.
• Push the excess wire back into the
opening and plug the wall opening to
prevent drafts.
1Connection to terminal 1 at equipment control module
2Connection to terminal 2 at equipment control module
3Connection to terminal 3 at equipment control module
A & B Model 8081 or Model 8082 support module communication (optional)
T1 & T2 Remote temperature sensor (optional)
90-2168
32

90-2124
90-1713
FIGURE 5 – REMOTE
TEMPERATURE SENSOR
3
T1
T2
B
A
C
RC T3
T2T1 RSARSB T4
2
1
FIGURE 6 – MODEL 8081 OR 8082
SUPPORT MODULE
FIGURE 7 – MODEL 8083
SUPPORT MODULE
90-2169
8083
Module Red Black Yellow Green
8840
Thermostat 1 2 A B
REMOTE TEMPERATURE SENSOR
(OPTIONAL)
A remote temperature sensor can be
used for control if the thermostat is to
be mounted in a concealed location or
a remote sensor can be averaged with
the thermostat sensor to control a large
space.An8051ushmountor8053surface
mount remote temperature sensor can
be attached to the T1 and T2 terminals
and mounted in a recommended area.
The remote sensor must be enabled in the
installer setup menu, and once enabled
will override or be averaged with the
thermostat’s internal temperature sensor,
based on the setting.
Remote temperature sensor should
be mounted:
• On an interior wall, in a frequently
occupied space.
• Approximately5feetaboveoor.
• At least 18” from outside wall.
• Using less than 300 feet of wire.
Do not mount remote sensor:
• Behind doors, in corners or other dead air
spaces.
• Indirectsunlight,nearlightingxtures,or
other appliances that give off heat.
• On an outside or unconditioned area wall.
• Intheowofasupplyregister,in
stairwells, or near outside doors.
• On a wall with concealed pipes or
ductwork.
• Near 120 VAC lines.
SUPPORT MODULE WIRING (OPTIONAL)
Up to 4 support modules can be wired for
remote sensing of temperature and/or
humidity.Eachsensorcanbeconguredfor
control or monitoring.
NOTE: Support modules should be wired
with CAT-5 wire. The total length of wire for
all support modules should not exceed
1000 feet.
EQUIPMENT CONTROL MODULE WIRING
Wire specications:
• 18-24 gauge thermostat wire
Installation notes:
• Ensure power at the HVAC equipment is off.
• Loosen screw terminals, insert stripped wire
and re-tighten.
• Use zip tie to route wiring through the wiring
channels.
1Connection to terminal 1 at thermostat
2Connection to terminal 2 at thermostat
3Connection to terminal 3 at thermostat
RAT Return air temperature sensor (optional)
LAT Leaving air temperature sensor (optional)
ODT Outdoor temperature sensor (included)
C24VAC common
R24VAC
RC 24VAC cooling
RH 24VAC heating
WFirst stage heat (conventional)/auxiliary (heat pump)
W2 Second stage heat (conventional)/ auxiliary (heat pump)
W3 / B Third stage heat (conventional)/reversing valve (heat pump)
YFirststagecooling(conventional)/rststagecompressor(heatpump)
Y2 Second stage cooling (conventional)/second stage compressor (heat pump)
Y3 / 0 Third stage cooling (conventional)/reversing valve (heat pump)
GFan
LSystem fault indicator (heat pump only) (optional)
CEQ 24VAC common from heat pump for system fault indicator (optional)
HUM Humidier
DHnc & DHcom Normallycloseddehumidiercontrol
DHno & DHcom Normallyopendehumidiercontrol
VENT Ventilation
EAC Electronic Air Cleaner
90-2282
54

OUTDOOR TEMPERATURE SENSOR (INCLUDED)
Outdoor temperature can be measured by installing an 8052 sensor to the ODT terminals
and enabling the outdoor sensor in the installer setup menu. When an outdoor sensor is
installed, the features below will be enabled.
In heat pump mode the outdoor temperature sensor can be used to efciently utilize an
air source heat pump:
• When the outdoor temperature is less than the Low Balance Point, the heat pump will be
locked out and only auxiliary heating will be used to provide heating.
• When the outdoor temperature is higher than the High Balance Point, the auxiliary
heating will be locked out and only the heat pump will be used to provide heating.
Indoor Air Quality functions can use the outdoor temperature sensor to:
• Controlhumidicationsetpointbasedonoutdoortemperaturetopreventcondensation
• Lockouthumidicationfortemperaturesover60°Forbelow-30°F.
• Lock out ventilation based on high and/or low outdoor temperatures.
• Display outdoor temperature on thermostat.
Outdoor temperature sensor
should be mounted:
• On side of building out of
direct sunlight (north side
recommended).
• Above snow line.
• At least 3 feet away from exhaust
vents and condensing lines.
• Using less than 300 feet of wire.
• Do not route wires along
120 VAC lines.
OPTIONAL WIRELESS OUTDOOR TEMPERATURE AND HUMIDITY SENSOR
Forinstallationswhereitisdifculttowiretheincluded8052outdoortemperaturesensor,
a Model 8056 wireless outdoor sensor can be used. The Model 8056 module has two radio
units, one that is placed on the equipment control module as shown below, and a second
radio that is placed outside. See the Model 8056 Installation Instructions for detailed
directions regarding installation.
RETURN AIR TEMPERATURE SENSOR (OPTIONAL)
Return air temperature can be measured by attaching an 8052 sensor to the RAT
terminals. The return sensor must be enabled in the installer setup menu. The return air
temperature sensor provides protection in the event that the equipment control module
loses connection with the thermostat. In the event that the thermostat connection is lost,
the equipment control module will use the return air temperature sensor to maintain a
temperature greater than 40°F and less than 100°F.
1. Locate the AprilAire Model 8052
sensor in the return trunk.
2. Mount the sensor according
to the installation instructions
provided with the sensor.
3. Wire the sensor to the
equipment control module RAT
terminals.
LEAVING AIR TEMPERATURE SENSOR (OPTIONAL)
Leaving air temperature can be measured by attaching an 8052 sensor to the LAT
terminals. The leaving air temperature sensor measurement is displayed during the
installer test for diagnostic purposes.
IMPORTANT: Do not mount the sensor in direct line-of-sight of the heat exchanger, cooling
coils, or UV lights as this may cause the sensor to report false temperature readings.
1. Locate the AprilAire Model 8052 sensor in the supply trunk, after the heat exchanger
and cooling coils. (See shaded areas in FIGURE 12 below.)
2. Mount the sensor according to the installation instructions provided with the sensor.
3. Wire the sensor to the equipment control module LAT terminals.
90-1714
90-1715
90-171690-690
FIGURE 8
FIGURE 11
FIGURE 13FIGURE 12
FIGURE 9 FIGURE 10 –
OUTDOOR
SENSOR
90-1733 90-1733
LOCATE
SENSOR IN
SHADED
AREA.
76

HVAC WIRING DIAGRAMS
W
W2
W3
Y
Y2
Y3
G
HC HP
EQ
3
C
RC
RH
L
G
O
Y2
Y
B
W2
W
R
C
TRANSFORMER
2nd HEATING
1st HEATING
THERMOSTAT
FAN
1st COOLING
2nd COOLING
2
1
3rd HEATING
3rd COOLING
C
R
W
W2
B
Y
Y2
O
G
L
RH
RC
C
3
EQ
HPHC
G
Y3
Y2
Y
W3
W2
W
FAULT DETECT
REVERSING VALVE
THERMOSTAT
REVERSING VALVE
1
2
2nd COMPRESSOR
1st COMPRESSOR
FAN
1st HEATING
2nd HEATING
HEAT PUMP
TRANSFORMER
HEATING TRANSFORMER
COOLING TRANSFORMER
C
R
W
W2
B
Y
Y2
O
G
L
RH
RC
C
3
EQ
HPHC
G
Y3
Y2
Y
W3
W2
W
TRANSFORMER
THERMOSTAT
1
2
2nd COOLING
1st COOLING
FAN
1st HEATING
2nd HEATING
3rd HEATING
3rd COOLING
1RAND CCAN BE
POWERED FROM THE
HVAC EQUIPMENT
TRANSFORMER OR ANY
OTHER CONSTANTLY
POWERED 24VAC
SOURCE.
1
90-1717
90-1719
90-1718
FIGURE 14 – CONVENTIONAL HEAT/COOL SINGLE TRANSFORMER (USE JUMPER)
FIGURE 16 – HEAT PUMP SINGLE TRANSFORMER (USE JUMPER WIRE)
THERMOSTAT
TRANSFORMER
W
W2
W3
Y
Y2
Y3
G
HC HP
EQ
3
C
RC
RH
L
G
O
Y2
Y
B
W2
W
R
C
HEAT PUMP TRANSFORMER
HEATING TRANSFORMER
1
FAULT DETECT
REVERSING VALVE
REVERSING VALVE
2nd HEATING
1st HEATING
FAN
1st COMPRESSOR
2nd COMPRESSOR
2
1
1R AND C CAN BE
POWERED FROM THE
HVAC EQUIPMENT
TRANSFORMER OR ANY
OTHER CONSTANTLY
POWERED 24VAC
SOURCE.
90-1720
FIGURE 17 – HEAT PUMP TWO TRANSFORMER (REMOVE JUMPER WIRE)
FIGURE 15 – CONVENTIONAL HEAT/COOL TWO TRANSFORMER (REMOVE JUMPER)
98

INDOOR AIR QUALITY WIRING DIAGRAMS
TRANSFORMER
TRANSFORMER
TRANSFORMER
VNT
DH
HUM
EAC
DH
DHnc
com
no DEHUMIDIFIER
NORMALLY
CLOSED DAMPER
HUMIDIFIER
PILOT RELAY FOR
120 VAC TO EAC
no
com
nc
DH
DH
EAC
HUM
DH
VNT
TRANSFORMER
HUMIDIFIER
NORMALLY
CLOSED DAMPER
DEHUMIDIFIER
PILOT RELAY FOR
120 VAC TO EAC
90-1721
90-1722
FIGURE 18 – INDOOR AIR QUALITY WIRING WITH SEPARATE TRANSFORMERS
FIGURE 19 – INDOOR AIR QUALITY WIRING WITH A SINGLE TRANSFORMER
POWER & RESET OPTIONS
The equipment control module is powered from 24VAC. The thermostat is powered from the
equipment control module. In the case of power loss the thermostat will maintain the clock
for 24 hours. The thermostat has a memory backup that saves the thermostat settings in
case of power interruption.
The factory reset is located in the Installer Tools option of the Installer Menu. See Installer
System Settings section for details.
SETUP & TESTING
INSTALLER SETUP WIZARD
Thersttimethethermostatispoweredup(orafterafactoryreset)itwillentertheInstaller
Setup Wizard. All installer settings can be set in this process. The installer settings are also
accessible in the MENU by pressing the Contractor Info button for 10 seconds.
Import USB settingswillbetherstscreenthatyousee(thebuttonwillbegrayedoutuntil
a USB drive is inserted).
• If you have a USB drive with installer
setuplesonit,insertitintotheUSB
connector (on the lower left corner)
toimportale.
• Or press Skip to proceed with the
Installer Setup Wizard.
NOTE:Installersetuplescanbe
created from the Export Setup option
found under Installer Menu > Installer
Tools > Export Setup.
HVAC INSTALLER SYSTEM SETTINGS TABLES
The following tables contain the system settings and their details. Default settings are shown
in bold. Some settings are only available dependent upon the value of other settings.
TABLE 1 – GENERAL SYSTEM SETTINGS
System setting Description Factory default setting (bold) and setting range
Connection Type Selects if the thermostat connects with an
automation system or an AprilAire account.
Automation System
AprilAire Cloud
Installer
Temperature Scale
This selection only effects the installer setup
menus.
Fahrenheit
Celsius
Contractor
Information Input Enter contractor’s contact information. Company, Phone, Email, Web
1110

TABLE 2 – THERMOSTAT SYSTEM SETTINGS
System setting Description Factory default setting (bold) and setting range
Equipment Type NOTE: Equipment Type related settings will
return to defaults if this is changed.
Heat/Cool
Heat Pump
Control Setup Used to lockout heating or cooling
outputs. (Heat/Cool mode only.)
Heat & Cool
Heat Only
Cool Only
Heat Pump Auxiliary
Type
Selects auxiliary type. (Heat Pump mode
only.)
Gas/Oil Heat
Electric Heat
Fan Control In Heating
Selects thermostat or equipment to
control the fan in heating. (Heat/Cool
mode only.)
Gas/Oil Heat
Electric Heat
Number of
Compressor Stages
Select number of compressor stages.
(Heat Pump mode only.)
One
Two
Number of Auxiliary
Heat Stages
Select number of auxiliary heat stages.
(Heat Pump mode only.)
One
Two
Number of Stages of
Heat
Select number of heat stages. (Heat/Cool
mode only.)
One
Two
Three
Number of Stages of
Cool
Select number of cool stages. (Heat/Cool
mode only.)
One
Two
Three
Remote Temperature
Sensor Installed?
Select if the remote sensor is attached,
and uses backup, or is averaged with
built-in.
No
Yes
Yes (fallback built-in)
Yes (average w/built-in)
Return Air Temperature
Sensor Installed?
Select if return air temperature sensor is
attached or not.
No
Yes
Outdoor Temperature
Sensor Installed?
Select if outdoor sensor is attached or
not.
No
Yes
Automation
Display Support
Modules
Select if support module values are
displayed on Monitored Climate screen
under Status.
No
Yes
Number of Controlling
Support Modules Temp
Selectnumberofsensorsconguredto
be controlling temperature. 0-8
Number of Controlling
Support Modules RH
Selectnumberofsensorsconguredto
be controlling RH. 0-4
Schedule Enables or disables programmable
schedule.
Enabled
Disabled
Progressive Recovery Enables or disables progressive recovery. Enabled
Disabled
Display Away Button?
Away allows the user to set the
thermostattoapredenedsetpointusing
asinglebuttonpress.Thepredened
setpoints can be selected in the User
Settings.
No
Yes
TABLE 2 – THERMOSTAT SYSTEM SETTINGS
System setting Description Factory default setting (bold) and setting range
Display Heat Blast
Button?
Select if the Heat Blast button is
displayed.
No
Yes
Blast Offset Amount of heating when Heat Blast is
initiated.
3°F (1.5°C)
4°F (2°C)
5°F (2.5°C)
Extended Fan – Heat Extends fan operation after heat call
ends.
Disabled
Enabled
Extended Fan – Cool Extends fan operation after cool call ends. Disabled
Enabled
Auto Changeover Enable or disable Auto Changeover mode. Disabled
Enabled
DeadBand Auto Changeover mode deadband. 3°F (1.5°C)
2 to 9°F (1 to 4.5°C)
Auto Changeover Time Minimum time between heating and
cooling calls.
4 Minutes
1 to 5 Minutes
Internal Temperature
Sensor Offset
Field adjustment of controlling
temperature sensors.
0°F (0°C)
-4 to 4°F (-2 to +2°C)
Internal RH% Sensor
Offset Field adjustment of internal RH sensor. 0 -5 to 5
Equipment Minimum
On Time Minimum on time for heating and cooling. 2 Minutes 1 to 5 Minutes
Heating Minimum Off
Time Minimum off time for heating. 2 Minutes 1 to 5 Minutes
Compressor Minimum
Off Time
Minimum off time for compressor
protection.
5 Minutes
1 to 5 Minutes
Outdoor Temperature
High Balance Point
Enable or disable high balance point
(Available if ODT is installed.)
Enabled
Disabled
Select High
Temperature Balance
Point
If outside temperature is above the high
balance point the aux heat operation is
not allowed. (Available if high balance
point is enabled.)
65°F (14.5°C)
0 to 80°F (-18 to 22°C)
Outdoor Temperature
Low Balance Point
Enable or disable low balance point
(Available if ODT is installed.)
Enabled
Disabled
Select Low
Temperature Balance
Point
If outside temperature is below the low
balance point the compressor operation
is not allowed. (Available if low balance
point is enabled.)
20°F (-8°C)
0 to 60°F (-18 to 12°C)
Stage Rate Accumulation of equipment run time in
staging determination.
Enabled
Disabled
Factor
1 = more rapid staging of equipment
(comfort),
5 = slower staging of equipment
(economy).
2
1 to 5
First Stage Differential First stage differential. 1°F (0.5°C)
1 to 9°F (0.5 to 4.5°C)
1312

TABLE 2 – THERMOSTAT SYSTEM SETTINGS
System setting Description Factory default setting (bold) and setting range
Second Stage
Differential Second stage differential. 1°F (0.5°C) 1 to 9°F (0.5 to 4.5°C)
Third Stage Differential Third stage differential. 1°F (0.5°C)
1 to 9°F (0.5 to 4.5°C)
Fourth Stage
Differential Fourth stage differential. 1°F (0.5°C) 1 to 9°F (0.5 to 4.5°C)
Service HVAC Reminder The period for displaying the HVAC
Service reminder message.
Disabled
Enabled
Number of Months for
Recurrence
Select number of months for displaying
reminder.
12 Months
1 to 12 Months
INDOOR AIR QUALITY SYSTEM SETTINGS TABLES
The following tables contain the Indoor Air Quality system settings and their details. Default
settings are shown in bold. Some settings are only present dependent upon the value of
other settings.
The use of an outdoor temperature sensor (recommended) enables additional Indoor Air
Quality functionality.
Please refer to the Model 8840 Owner’s Manual for further information about thermostat
features.
NOTE:Refertomanualsforhumidier,dehumidier,aircleaner,andventilationproductsfor
recommended installation and operation.
TABLE 3 – HUMIDIFIER SYSTEM SETTINGS
System setting Description Factory default setting (bold) and setting range
HumidierInstalled?
Selectsifahumidierisinstalled.Yes/On
HVAC is used for applications where the
humidierisinstalledontheHVACduct.
Yes/Standalone is used for application
wherethehumidierisindependentof
the HVAC system. (If set to No, no other
humidiersettingswillbeavailable.)
No
Yes/On HVAC
Yes/Standalone
Display Button? NOTE: Only available if Humidier Installed
is set to No.
Yes
No
Outdoor Temperature
Sensor Installed? Select if outdoor sensor is attached or not. No Yes
HumidierMode
Selects auto or manual mode. Auto
mode controls humidity based on the
humidity setting and outdoor temperature.
Manual mode controls humidity based
on the %RH setpoint. (Auto mode is only
available if Outdoor Sensor is set to Yes or
Automation.)
Auto
Manual
TABLE 3 – HUMIDIFIER SYSTEM SETTINGS
System setting Description Factory default setting (bold) and setting range
AllowedHumidier
Operation
Selectswhenhumidicationisallowedto
occur relative to heating and fan operation.
WithoutFanallowshumidicationto
occur without the HVAC fan. This option
shouldonlybeusedwhenthehumidier
is independent of the HVAC system.
NOTE: Without Fan is only available
when Humidier Installed is set to Yes/
Standalone.
Heat Only
Heat or Fan
Forces Fan
Without Fan
CAUTION: When Humidier Operation is set to Without Fan the thermostat will turn on
humidicationwithoutenergizingtheHVACfan.Donotselectthisoptionwhenthehumidier
isinstalledontheHVACduct.Withoutairowmoisturecanaccumulateintheductresultingin
signicantdamage.
Humidity Deadband
Select the minimum difference between
thehumidieranddehumidiersetpoints.
(Onlyavailableifbothahumidierand
dehumidierareinstalled.)
10%
10 to 20%
HumidierReminder Selects when the Change Water Panel
message is displayed.
Off
300h Valve
600h Valve
1 per season
2 per season
Single or First
Reminder Appears
Determinesthemonththerst(oronly)
Change Water Panel message is displayed.
October
November
December
January
February
March
April
May
June
July
August
September
Second Reminder
Appears
Determines the month the second Change
Water Panel message is displayed.
October
November
December
January
February
March
April
May
June
July
August
September
1514

TABLE 4 – DEHUMIDIFIER SYSTEM SETTINGS
System setting Description Factory default setting (bold) and setting range
DehumidierType
Installed?
Selectsifadehumidierisinstalled.(Ifset
to None,nootherdehumidiersettingswill
be available.)
None
Whole Home
Air Conditioner
Display Button? NOTE: Only available if Dehumidier
Installed is set to None.
Yes
No
Disable
Dehumidication
During Cooling?
Selectsifadehumidierisdisabledduring
a cooling call.
Yes
No
DehumidierForces
Fan?
Selectsifdehumidicationcanturnon
the fan.
Yes
No
Dehumidier
Overcooling Limit
Selects the amount of overcooling that
canoccurfordehumidication.(Only
available if Dehumidier Type is set to Air
Conditioner.)
1°F (0.5°C)
2°F (1°C)
3°F (1.5°C)
Dehumidier
Reminder
The period for displaying the
Dehumidication Service Reminder
message.
Disabled
Enabled
Number of Months for
Recurrence
Select number of months for displaying
reminder.
12 Months
1 to 12 Months
Dehumidify in
Vacation Hold?
Selectsifdehumidicationwiththeair
conditioner is done in vacation mode.
No
Yes
Vacation Hold Low
Temperature Limit
Sets the lowest temperature the air
conditioner will cool to, to meet RH
setpoint in Vacation Mode. (Only
available if Dehumidier Type is set to Air
Conditioner.)
75°F (24°C)
70 to 85°F (21 to 29.5°C)
Humidity Deadband
Select the minimum difference between
thehumidieranddehumidiersetpoints.
(Onlyavailableifbothahumidierand
dehumidierareinstalled.)
10%
10 to 20%
TABLE 5 – AIR CLEANING SYSTEM SETTINGS
System setting Description Factory default setting (bold) and setting range
Air Cleaner Installed?
Selects if an air cleaner is installed. (If set
to No, no other air cleaner settings will be
available.)
No
Yes
Display Button? NOTE: Only available if Air Cleaning
Installed is set to No.
Yes
No
Air Cleaner Reminder The period for displaying the Change Air
Filter message.
Disabled
Enabled
Number of Months for
Recurrence
Select number of months for displaying
reminder.
12 Months
1 to 12 Months
TABLE 6 – FRESH AIR SYSTEM SETTINGS
System setting Description Factory default setting (bold) and setting range
Fresh Air Vent
Installed
Selects if ventilation is installed. (If set to
No, no other ventilation settings will be
available.)
No
Yes
Display Button? NOTE: only available if Fresh Air Installed
is set to No.
Yes
No
Fresh Air Setup
Type
Selectsifventilationiscongured
through the Code setup or Comfort.
Comfort setup has more lockout options.
Code setting ensures missed lockout
time is made up.
Comfort
Code
Number of
Bedrooms
Selects the number of bedrooms to be
used for the Calculated Minutes per Hour.
3 Bedrooms
1 to 10 Bedrooms
Home Size Selects the size of the home to be used
for the Calculated Minutes per Hour.
2500 SQ FT
500 to 7500 SQ FT
Measured CFM Selects the ventilation CFM to be used for
the Calculated Minutes per Hour.
110 CFM
30 to 250 CFM
Calculated
Minutes per Hour Displays the Fresh Air Time calculated. None Range 6 to 60 Minutes
Override Manual adjustment of Calculated
Minutes per Hour.
(Calculated Minutes per Hour)
Range 6 to 60 Minutes
Outdoor
Temperature
Sensor Installed?
Select if outdoor sensor is attached or
not.
No
Yes
Enable High Vent
RH Limit
Selects if ventilation is disabled if the
indoor RH exceeds the indoor RH limit.
(Only available if Fresh Air Setup is set to
Comfort.)
Yes
No
High Vent RH Limit
Sets the ventilation indoor RH lockout
limit. (Only available if Enable High Vent
RH Limit is set to Yes.)
55%
45% to 70%
Enable Low Vent
RH Limit
Selects if ventilation is disabled if the
indoor RH exceeds the indoor RH limit.
(Only available if Fresh Air Setup is set to
Comfort.)
No
Yes
Low Vent RH Limit
Sets the ventilation indoor RH lockout
limit. (Only available if Enable Low Vent
RH Limit is set to Yes.)
20%
10% to 30%
Enable High Vent
Temperature
Limit
Enables high ventilation temperature
lockout limit. (Only available if Outdoor
Sensor is set to Installed or Automation.)
No
Yes
High Vent
Temperature
Limit
Sets high ventilation temperature lockout
limit. (Only available if Enable High Vent
Temperature Limit is set to Yes.)
100°F (38°C)
85°F to 105°F (29°C to 41°C)
Enable Low Vent
Temperature
Limit
Enables low ventilation temperature
lockout limit. (Only available if Outdoor
Sensor is set to Installed or Automation.)
No
Yes
1716

WI-FI SETUP
The 8840 can be connected to a Wi-Fi network either at the thermostat or another Wi-Fi
device with a web browser.
STEP 1: Verify the thermostat is in Wi-Fi Connection Mode.
The thermostat by default will be in
Wi-FiConnectionMode.Toconrm
that the thermostat is in Wi-Fi
Connection Mode, verify that the
radio bars on the thermostat are
strobing as shown in FIGURE 20.
NOTE: If the thermostat is not in
Wi-Fi Connection Mode, refer to the
online owner’s manuals found at
aprilaire.com.
FIGURE 20
TABLE 6 – FRESH AIR SYSTEM SETTINGS
System setting Description Factory default setting (bold) and setting range
Low Vent
Temperature
Limit
Sets low ventilation temperature lockout
limit. (Only available if Enable Low Vent
Temperature Limit is set to Yes.)
10°F (-12°C)
-10°F to 40°F (-24°C to 6°C)
HVAC Fan with
Vent
Selects if ventilation forces the fan on.
(Yes with high and low limits is only
available if Outdoor Sensor is set to
Installed or Automation.)
Yes
Yes with high and low limits
No
Enable
High Mixing
Temperature
Enables high mixing temperature. (Only
available is HVAC Fan with Vent is set to
Yes with high and low limits.)
No
Yes
High Mixing
Temperature
Sets the high mixing temperature.
(Only available if Enable High Mixing
Temperature is set to Yes.)
80°F or (26°C)
60°F to 105°F (14°C to 41°C)
Enable Low Mixing
Temperature
Enables low mixing temperature. (Only
available is HVAC Fan with Vent is set to
Yes with high and low limits.)
No
Yes
Low Mixing
Temperature
Sets the Low mixing temperature.
(Only available if Enable Low Mixing
Temperature is set to Yes.)
40°F (6°C)
0°F to 50°F (-18°C to 12°C)
Fresh Air Service
Reminder
The period for displaying the SERVICE
FRESH AIR message.
OFF
1 to 12 months or OFF to disable
CONNECT TO A NETWORK
USING THE THERMOSTAT
STEP 2: Navigate to the Connect
without App screen: Menu > Wi-Fi
Settings > Advanced > Connect
without App.
STEP 3: Select a network from the
list of scanned networks.
STEP 4: Enter a password and press
Done.
STEP 5: Press Done on the
Credentials screen to connect.
CONNECT TO A NETWORK USING A BROWSER
STEP 2: Connect to the thermostat using a computer or
mobile device.
On your computer or mobile device, scan for
available networks. The thermostat should appear
asAPRILAIRE8840followedbyauniqueidentier,
corresponding to the last 6 digits of the MAC address.
Connecttothethermostatyouwanttocongure.
If you are installing multiple thermostats, the MAC
address of each thermostat will be displayed on the
Wi-Fi Settings screen, and can be found on the back of
the thermostat.
STEP 3:CongurethethermostattoconnecttotheWi-Fi
network.
Open a web browser on your computer or mobile device.
In the browser enter: http://192.168.1.99/index.html
In the web browser interface select the network you want
to connect the thermostat to, and enter the network’s
security credentials.
STEP 4: Verify the thermostat is connected to the Wi-Fi
network.
Once all the required information is entered in the
web browser interface, the thermostat will connect to
the Wi-Fi network you selected. After the thermostat
is connected to the Wi-Fi network, the thermostat will
display the radio bars based on the Wi-Fi signal strength.
NOTE: If you are not using the thermostat with a home
automation system, but are instead using an AprilAire
account to communicate with the thermostat, refer to
Wi-Fi Thermostat App User Guide and then Start Up
Guide on aprilaire.com for instructions on connecting to
Wi-Fi and registering to an AprilAire account.
INSTALLER SYSTEM TEST
The Installer Test can be accessed
from the Installer Menu. All equipment
outputsthatareconguredinthe
installer settings can be turned
on and off for testing equipment.
Minimum on and off times are not
enforced while in this mode.
1918

QUICK REFERENCE TO CONTROLS & DISPLAY
HOME SCREEN
INSTALLER MENU
EQUIPMENT CONTROL MODULE LEDs
POWER/STATUS
On solid during normal operation. Flashes
when connection to the thermostat is lost
and at power-up while the thermostat
connection is being established.
HEATING On when heating outputs are active.
COOLING On when cooling outputs are active.
FAN On when fan output is active.
HUMIDIFIER Onwhenhumidieroutputisactive.
DEHUMIDIFIER Onwhendehumidieroutputisactive.
VENTILATION On when ventilation output is active.
AIR CLEANING On when air cleaner output is active.
MAIN MENU
NOTE: SCREEN BRIGHTENS AFTER FIRST TOUCH.
OUTDOOR
TEMPERATURE
& HUMIDITY
(IF INSTALLED)
HEATING AND
COOLING
EQUIPMENT
STATUS
HOLD
MENU &
STATUS
SYSTEM MODE
SELECTION
DETAILED
EQUIPMENT
STATUS
HEAT BLAST
MODE & STATUS
(IF INSTALLED)
WEATHER
FORECAST &
ALLERGY REPORT
ACTIVE ALERTS
& ALERT
SETTINGS
CURRENT SCREEN
RELATED HELP
MAIN MENU
HUMIDIFIER AND
OR DEHUMIDIFIER
INDOOR AIR
QUALITY SCREEN
& SIMPLE STATUS
AIR CLEANING
INDOOR AIR
QUALITY SCREEN
& SIMPLE STATUS
COOL SETTING CURRENT DATE AND TIME
(AUTOMATICALLY UPDATED IF
CONNECTED TO INTERNET)
WI-FI INDICATOR
(STROBES IN
SETUP MODE)
FRESH AIR
INDOOR AIR
QUALITY SCREEN
& SIMPLE STATUS
AWAY MODE
& STATUS
(IF INSTALLED)
FAN MODE
SELECTION
ROOM
TEMPERATURE
& HUMIDITY
HEAT SETTINGTHERMOSTAT
NAME
SET SCREEN
BRIGHTNESS
AND SCREEN
SAVER
SET DATE & TIME
CONNECT TO
WI-FI NETWORKS
SET SCHEDULE
VIEW CONTRACTOR
INFORMATION OR
ACCESS INSTALLER
MENU WITH
10 SECOND PRESS
& HOLD
SET VACATION
HOLDS
TEMPERATURE
SCALE, LOCKOUTS,
AWAY MODE
SETTING
(IF ENABLED)
CLEAN DISPLAY
(TOUCHSCREEN
IS OFF FOR
30 SECONDS)
USB SETTINGS
FILE IMPORT, ETC
THERMOSTAT &
HVAC SYSTEM
CONFIGURATION
HUMIDIFIER
CONFIGURATION
DEHUMIDIFIER
CONFIGURATION
EQUIPMENT
OUTPUT TESTS
IMPORT/EXPORT
USB INSTALLER
SETTINGS FILES,
FACTORY RESET
VENTILATION
CONFIGURATION
AIR CLEANER
CONFIGURATION
2120

THERMOSTAT FEATURES
• Remote access and control over Wi-Fi.
• Indoor air quality control.
−Humidicationautomaticormanualcontrol.
−Dehumidication.
−Event-Based™ air cleaning.
−Ventilation with temperature and humidity limits.
• Temperature control.
• Heat Blast® raises the room temperature 3°F to 5°F.
• One touch Away.
• Support for optional wireless outdoor temperature sensor.
• Large touch screen with adjustable backlight.
• 7 day programmability.
• Displays room temperature, room humidity, temperature setting, and optional outdoor
temperature.
• Airlter,humidier,dehumidier,andHVACservicereminders.
• Programmable fan control with fan circulation mode.
• Easy to use temperature control can override program schedule at any time.
• Progressive recovery ensures proper temperature at the start of a program event.
• Built in compressor protection prevents damage to your equipment.
• System test mode.
TROUBLESHOOTING
DISPLAY IS BLANK
If Power LED is not illuminated at the
equipment control module check the
following:
• Check circuit breaker and reset if
necessary.
• Make sure power switch at heating &
cooling system is on.
• Make sure furnace door is closed securely.
HEATING SYSTEM DOES NOT RESPOND
(“HEATING” APPEARS ON SCREEN)
• Check for 24VAC at the equipment on the
secondary side of the transformer between
power and common. If voltage is not
present, check the heating equipment to
ndthecauseoftheproblem.
• Check for 24VAC between the heat terminal
(W) and the transformer common. If 24VAC
is present, the thermostat is functional.
Checktheheatingequipmenttondthe
cause of the problem.
• Check for loose or broken wires between
the thermostat and the heating equipment.
COOLING SYSTEM DOES NOT RESPOND
(“COOLING” APPEARS ON SCREEN)
• Check for 24VAC at the equipment on the
secondary side of the transformer between
power and common. If voltage is not
present, check the cooling equipment to
ndthecauseoftheproblem
• Check for 24VAC between the cooling
terminal (Y) and the transformer common.
If 24VAC is present, the thermostat is
functional. Check the cooling system to
ndthecauseoftheproblem.
• Check for loose or broken wires between
the thermostat and the cooling equipment.
FAN DOES NOT TURN ON IN A CALL FOR HEAT
• Check Installer Setting Fan Control In
Heating / Heat Pump Auxiliary Type, to
make sure the fan control is properly set to
match the type of system.
HEAT PUMP ISSUES COOL AIR IN HEAT
MODE, OR WARM AIR IN COOL MODE
• Check wiring at the terminal block to
conrmthereversingvalveisconnectedto
the proper terminal. O is active in cooling
and B is active in heating.
HEAT/COOL BOTH ON AT SAME TIME
• Check Installer Setting Equipment Type, to
make sure it is set to match the installed
heating/cooling equipment.
• Check to make sure heating and cooling
wires are not shorted together.
HEATING EQUIPMENT IS RUNNING IN
COOL MODE
• Check Installer Setting Equipment Type, to
make sure it is set to match the installed
heating/cooling equipment.
“HEATING” IS NOT DISPLAYED
• Check Installer Setting Control Setup is set
correctly.
• Change the System Mode to Heat, and set
the temperature level above the current
room temperature.
“COOLING” IS NOT DISPLAYED
• Check Installer Setting Control Setup is set
correctly.
• Change the System Mode to Cool, and set
the temperature level below the current
room temperature.
2322

B2206592E • 61001172 • 6.22
© 2022 AprilAire | aprilairepartners.com | 800.334.6011
U.S. Patent Numbers 8,146,376, 8,596,078 and other patents pending.
AprilAire reserves the right to change specications without notice.
SPECIFICATIONS
ENVIRONMENT
Temperature (shipping) -30° to 150°F (-34° to 65°C)
Temperature thermostat (operating) 32° to 120°F (0° to 48°C)
Temperature equipment control module
(operating) 32° to 158°F (0° to 70°C)
Relative humidity Operating: 5% to 90% R.H. (non-condensing)
ELECTRICAL
Operating voltage 24VAC (18–30VAC)
Current Maximum: 2.5A (total), 1.0A (single output)
Maximum surge current: 5A
CONTROL
Outdoor, Remote, Leaving and Return
temperature sensor Maximum distance: 300 feet
Room temperature measurement Display range: 32° to 99°F (0° to 40°C)
Return and Leaving temperature measurement Display range: -40° to 160°F (-40° to 71°C)
Outdoor temperature measurement Display range: -40° to 130°F (-40° to 55°C)
Setpoint temperature range Heat: 40° to 90°F (4° to 32°C)
Cool: 50° to 99°F (10° to 37°C)
Setpoint humidity range Humidication:10%to50%R.H.
Dehumidication:40%to90%R.H.