
Meritage IAQ Controls
Features & Benefits
Model
8840M
Shown
(Primary
thermostat)
Model 8810M
(Secondary thermostat)
Universal 2H/2C or 4H/2C HP
Event-Based™ Air Cleaning
Wi-Fi
IAQ Control Features & Benefits
Wi-Fi with IAQ Control
Integrated Indoor Air Quality Control
(Model 8840M)
Event-Based™ Air Cleaning
Fresh Air Ventilation Code or Comfort
mode set-up (Model 8840M)
Convenient One-Touch selection between
Fresh Air Ventilation modes
Model 8840M
Universal 3H/3C or 4H/2C HP
Event-Based™ Air Cleaning
Humidity and Ventilation
2 Part—3-Wire design
Full Color Wi-Fi touch screen
BUMPER to BUMPER
5-YEAR
WARRANTY
Color touch screen (Model 8840M)
Built-in dual fuel control
3-wire design (Model 8840M)
Maintenance reminders
Heat Blast™—schedule override (Model 8840M)
Works with all major home automation systems

IAQ Control Features
INDOOR AIR QUALITY SPECIFICATIONS
Intuitive User Interface
8840M
3-Wire Connection
Optional Return Air Temperature
Sensor (RAT) provides protection with
heating and cooling back-up control if
connection is lost
Equipment
Control Module
8 LEDs indicate HVAC
Equipment and IAQ
Accessory Status
Temperature Control
+ Universal Programmable Thermostat—3H/3C Conventional or 4H/2C Heat Pump
+ 7 day 4 events/day or non-programmable
+ Dual fuel operation
+ High and low balance points (must use ODT)
+ Screen lock-out to prevent unauthorized adjustments
+ Adjustable differential for all stages
+ Stage rate control uses equipment run time to control HVAC equipment staging
+ Progressive Recovery feature ensures that the setpoint is reached by the scheduled time
+ Heat Blast™ allows one touch control of heating to raise room temperature 3°F to 5°F
Humidity Control
Humidifier
+ Displays indoor RH on User Interface
+ Notifies when humidifier is active
+ Automatic humidity setpoint adjustment (must use ODT) or Manual Control
+ Water Panel® replacement reminder
Dehumidifier
+ Displays indoor RH on User Interface
+ Notifies when dehumidifier is active
+ Operates whole-home dehumidifier or air conditioner to dehumidify
+ Dehumidifier service reminder
+ Energizes HVAC blower when dehumidifying
Optional Leaving Air Temperature
Sensor (LAT) provides the supply air
temperature during the installer test
Included — Wired Outdoor
Temperature Sensor 8052 (ODT)
Model 8840M IAQ Control
The Model 8840M IAQ Control Thermostats consist of two components, the User Interface and the Equipment Control Module.
The User Interface, located in the living space, integrates all indoor air quality functions—heating/cooling, humidification/
dehumidification, air cleaning and ventilation in one attractive, easy-to-use, touch screen control. The User Interface offers
homeowners the ability to easily set all of their IAQ and HVAC products from one location in the living space. The primary
screen indicates how to easily activate and control set points. In addition, the display provides the homeowner with
confirmation that the equipment is operating at the desired control settings.
Fresh Air Ventilation
+ Provides fresh air with a motorized damper or an ERV/HRV
+ Notifies when ventilation is active
+ Control limits based upon outdoor temperature and RH
+ Can be set up to use ASHRAE 62.2 guidelines or timed ventilation
+ Provides fresh air with a powered Fresh Air Ventilator or Ventilator with Dehumidification
+ Notifies when ventilation is active
+ One-Touch selection for turning fresh air ventilation OFF, or setting fresh air ventilation to
Comfort mode (fresh air is limited during extreme outdoor temperatures or indoor RH)
Air Cleaning
+ Event Based™ Air Cleaning—4 selectable air cleaning events
– Constant Cleaning (24/7)
– Automatic (30 Min/Hr)
– Event Clean (3 Hr Cycle)
– Allergy (24 Hr Cycle)
+ Notifies when air cleaning is active
+ Media replacement reminder
+ Controls EAC with dedicated 24 VAC dry contact

Easy to Install & Maintain
+ Dual fuel operation (auto lockout of
compressor w/call for back-up heat)
+ Programmable (or non-programmable)
+ Remote indoor sensor option w/8051/8053
sensors (Model 8840M)
+ Temperature offset ± 4°
+ High and low balance point control (requires
8052 outdoor temperature sensor)
+ 3H/3C conventional and 4H/2C heat pump
(Model 8840M)
+ 2H/2C conventional and 4H/2C heat pump
(Model 8810M)
+ Configurable manual heat/cool or auto
changeover modes
+ Configurable for heating only or cooling only
operation (Model 8840M)
+ Large, easy-to-wire terminal block
+ Adjustable differential for 1st, 2nd, 3rd
and 4th stages
+ Service reminders for humidifier, air
cleaner, dehumidifier, ventilation
(Model 8840M), HVAC
Engineered for Excellence
+ Circulate fan mode
+ Programmable fan
+ Progressive recovery
+ Built-in equipment protection
+ Equipment stage identification
(Model 8840M)
+ Multiple hold options maximize comfort
and energy savings
- Vacation hold
- Customizable timed hold
- Permanent hold
+ Permanent memory—programming, time
and date aren’t lost during a power outage
+ Heat Blast™ allows one-touch control
of heating to raise room temperature
3°F to 5°F
+ 5-year warranty
Easy & Convenient to Use
+ 7" diagonal touch screen (Model 8840M)
+ 3.25" diagonal LCD with soft-touch keys
(Model 8810M)
+ Fully backlit w/constant low intensity
light option
+ Exclusive message center (provides
feedback and real language instructions)
(Model 8840M)
+ Displays room temperature, temperature
setting and outdoor temperature. Outdoor
temperature display requires 8052 sensor
(included).
+ “Copy” function for quick and easy
programming (Model 8840M)
+ Real time clock automatically adjusts
for daylight savings time
Dimensions
Model 8840M
User interface
7.1" x 4.4" x 1"
Equipment control
module
8.6" x 9.6" x 1.9"
Model 8810M
User interface
5.3" x 4.5" x 1.0"
Accessories
Model 8840M & 8810M
8052 Outdoor Temperature Sensor (Included with
Model 8840. Optional with Model 8810)
Model 8840M
8051 Flush Mount Indoor Temperature Sensor
8053 Surface Mount Indoor Temperature Sensor
8081 Temperature Support Module
8082 Temperature and RH Support Module
Return Air Temperature Sensor (RAT) optional
sensor provides protection with heating and
cooling back-up control if connection is lost
Leaving Air Temperature Sensor (LAT) optional
sensor provides the supply air temperature
during the installer test
Thermal Specifications
Control range:
Model 8840M
40° to 99°F
(4° to 32°C)
Display range: 32° to 99°F (0° to 40°C)
Accuracy: ± 1°F (± .5°C)
Storage temperature: -30° to 140°F
(-34.4° to 60°C)
Operating humidity: 5% to 90% relative
humidity non-condensing
Operating ambient temperature of user
interface: 32° to 120°F (0° to 48.9°C)
Operating ambient temperature of ECM:
32° to 158°F (0° to 70°C)
Shipping temperature range:
-30° to 140°F (-34.4° to 60°C)
Model 8810M
45° to 99°F
(7° to 32°C)
Electrical Specifications
24 VAC powered (18-30 VAC)
1 amp maximum load per terminal
2.5 amp total maximum load (all terminals)
Standard systems gas, oil, electric
Single stage/heat pump/multi-stage
Terminal Designations:
Model 8840M
User interface: 1, 2, 3, T1, T2, RSA, RSB
Equipment control module: 1, 2, 3, RAT, LAT,
ODT, C, R, RC, RH, W, W2, W3/B, Y, Y2, Y3/O, G,
L, CEQ, HUM, DHNO, DHNC, DHCOM, VENT, EAC
Model 8810M
Equipment control module: RC, R, W, Y, G, C, S1,
S2, 0/B, L, W2, Y2
AprilairePartners.com
Form No. 4038 • 286058 4.19
©2019 Aprilaire –Division of Research Products Corporation
P.O. Box 1467
Madison, WI 53701-1467
800.334.6011 F: 608.257.4357