Emerson 1F86U-42WF Thermostat Operation Manual

The Emerson 1F86U-42WF is a Sensi Wi-Fi Programmable Thermostat designed for single-stage, multi-stage, or heat pump systems, offering 7-day programming and remote control via a smartphone app. It features a backlit display, geofencing, humidity control, and easy installation with no common (C) wire required in most cases. Below are the key specifications and operation instructions.

1. Key Specifications 2. Operation Instructions 2.1. Initial Setup 2.2. Setting the Clock and Day 2.3. Operating in Non-Programmable Mode 2.4. Operating in Programmable Mode 2.5. Advanced Features 2.6. Troubleshooting 3. Installation Instructions 3.1. Remove Old Thermostat 3.2. Installing New Thermostat 3.3. Battery Location 3.4. Wiring and Terminal Functions

Key Specifications

Type: Programmable (7-day), universal Wi-Fi thermostat
Compatibility:
- Conventional systems (gas, oil, electric, millivolt, 24V)
- Heat pump systems (up to 4 heat/2 cool stages)
- Heat only, cool only, or heat/cool systems
- Not compatible with systems exceeding 30 VAC
Power Source:
- Battery: 2 AA alkaline batteries (Duracell or Energizer recommended)
- Hardwired: 20-30 VAC, NEC Class II, 50/60 Hz with common (C) wire (required for heat only, cool only, or heat pump systems)
- Power stealing assist for systems without C wire in most HVAC applications
Electrical Rating:
- Terminal Load: 1.5 A per terminal, 2.5 A max combined
- Rated Differentials: Heat (0.6°F/1.5°F), Cool (1.2°F/1.7°F), Heat Pump (1.2°F/1.7°F)
- Setpoint Range: 45°F to 99°F (7°C to 37°C)
Display: Backlit LCD display with large, easy-to-read characters
Operating Conditions:
- Ambient: 32°F to 105°F (0°C to 41°C)
- Humidity: 90% non-condensing max
- Shipping: -40°F to 150°F (-40°C to 65°C)
Dimensions: 5-7/8” W x 3-3/4” H x 1” D
Features:
- Wi-Fi connectivity for remote control via smartphone or tablet app
- Geofencing, flexible scheduling, and remote access
- Humidity control (humidification/dehumidification with compatible equipment)
- Automatic heat/cool changeover
- Keypad lockout and temperature limit settings
- Compressor protection (adjustable delay)
- Operates as a standard thermostat when not connected to Wi-Fi
- Contractor branding integration
- 5-year limited warranty
Thermostat Configuration Options:
- Single Stage (SS1): Gas, Oil, Electric, Heat Only, Cool Only, or Heat/Cool Systems - Maximum Stages Heat/Cool: 1/1
- Multi Stage (MS2): Gas, Oil, Electric - Maximum Stages Heat/Cool: 2/2
- Heat Pump (HP1): Single-stage compressor, up to 2 stages aux./emergency heat - Maximum Stages Heat/Cool: 3/1
- Heat Pump (HP2): Two-stage or two-compressor heat pump systems - Maximum Stages Heat/Cool: 4/2

Operation Instructions

Initial Setup

1. Insert Batteries: Install 2 AA alkaline batteries in the rear compartment above the battery compartment, removing the battery tag to activate. Replace when the battery icon shows low (approximately every 2 years).
2. Power On: If hardwired, ensure 20-30 VAC is supplied via the C terminal (required for heat only, cool only, or heat pump systems). The display should show the home screen with temperature and Wi-Fi status.
3. Configure System:

Press MENU, then hold CONFIG for 5 seconds to access INSTALLER CONFIG menu.
Select system type (SS1, MS2, HP1, HP2), fan settings (Auto, On, Prog), and options like compressor delay or keypad lockout.
For Wi-Fi setup, download the Sensi app on a smartphone or tablet, open the app, and follow the step-by-step instructions to connect the thermostat to your home Wi-Fi router.
Exit by pressing RUN SCHED or waiting for the display to return to normal.

Setting the Clock and Day

1. Press MENU, then select SET TIME.
2. Use up/down arrows to adjust hours, minutes, and AM/PM.
3. Select SET DAY and adjust to the current day of the week.
4. Press RUN SCHED to save and exit.
Note: Clock and day can also be set via the Sensi app for Wi-Fi-connected units.

Operating in Non-Programmable Mode

1. Select Mode: Press SYSTEM to choose HEAT, COOL, AUTO, EMER (for heat pumps), or OFF.
2. Adjust Temperature: Press up/down arrows to set the desired temperature.
3. Fan Control: Press FAN to select AUTO (runs only when heating/cooling) or ON (continuous).
4. Manual Override: Press HOLD and adjust temperature to bypass any schedule until RUN SCHED is pressed.
Note: The thermostat operates like a standard thermostat when not connected to Wi-Fi.

Operating in Programmable Mode

1. Factory Schedule: Pre-programmed with energy-saving settings (e.g., Heat: 70°F day, 62°F night; Cool: 78°F day, 82°F night). Press RUN SCHED to use defaults.
2. Custom Schedule:

Press MENU, then SET SCHEDULE, and select HEAT or COOL.
Choose 7-day programming for individual days.
Set times/temperatures for Morning, Day, Evening, Night periods for each day.
Save by pressing RUN SCHED.
Alternatively, use the Sensi app to set schedules remotely.

3. Temporary Override: Press up/down arrows to adjust temperature temporarily until the next period. The display shows “Temporarily Set To” with a minimum hold of 2 hours.
4. Permanent Hold: Press HOLD and adjust temperature to maintain it until RUN SCHED is pressed.
5. Disable Programming: Press MENU, hold CONFIG for 5 seconds, and set programming to P0 (non-programmable).

Advanced Features

1. Wi-Fi Connectivity: Connect to a Wi-Fi network via the Sensi app for remote control, geofencing, and scheduling. Register the thermostat in the app to ensure the latest firmware.
2. Humidity Control: For systems with humidification/dehumidification equipment, configure settings in the INSTALLER CONFIG menu (single-stage systems only). Press MENU, navigate to Humidity Control, toggle features on/off, and adjust set percentage (e.g., for dehumidification, overcool up to 3°F if no wired dehumidifier).
3. Keypad Lockout: Enable in INSTALLER CONFIG to restrict access. Unlock by pressing MENU and RUN SCHED simultaneously for 5 seconds.
4. Geofencing: When enabled via the Sensi app, adjusts temperature based on your smartphone’s location.
5. Compressor Protection: Automatically delays compressor restart (up to 5 minutes) to prevent damage.

Troubleshooting

No Display: Check battery polarity or replace batteries. Verify C wire connection for hardwired setups (required for heat only, cool only, or heat pump systems). Remove R/C wires and batteries for 2 minutes to reset.
No Heat/Cool: Ensure SYSTEM is set to HEAT/COOL, setpoint is above/below room temperature, and wiring is correct. Check for compressor delay (up to 5 minutes). Verify SYSTEM is not in OFF or EMER mode. If issue persists, contact a professional technician.
System Runs Continuously: In COOL mode, select COOL (not AUTO) and set FAN to AUTO. Verify setpoint settings. Check for remote app control overriding settings.
Inaccurate Temperature: Calibrate in INSTALLER CONFIG or relocate thermostat away from drafts/heat sources. Use a separate thermometer for calibration.
Wi-Fi Connection Issues: Ensure the thermostat is within router range. Check Wi-Fi status icon (blank when off). Reconnect via the Sensi app, ensuring correct network credentials.
Thermostat Stops Heating Periodically: If the thermostat stops heating every few days, toggle SYSTEM to OFF until the screen goes grey and “Heating” disappears, then set back to HEAT. Repeat if necessary. If persistent, the thermostat may need replacement.
Erratic Operation: Reset by removing batteries and reinserting after 2 minutes. If controlled via the app, ensure no one is adjusting settings remotely.

Installation Instructions

Warning: Thermostat installation and all components shall conform to Class II circuits per the NEC code. Verify compatibility with a qualified technician if unsure.

Remove Old Thermostat

Turn off power at the main fuse or circuit breaker until installation is complete.
Remove the front cover of the old thermostat. With wires attached, remove the wall plate.
Take a picture of the wiring and mark wires for terminal identification using labels provided with the new thermostat.
Disconnect wires one at a time, ensuring they do not fall back into the wall.

Installing New Thermostat

Pull the thermostat body off the base. Do not force or pry to avoid damage.
Place base over the hole in the wall and mark mounting hole locations using the base as a template.
Move base out of the way and drill mounting holes. Use plastic screw anchors if existing holes are too large.
Fasten base snugly to the wall using two mounting screws. Leveling is for appearance only.
Connect wires to the terminal block using the appropriate wiring schematic (see Wiring section). If separate RC and RH wires exist, clip the RC/RH jumper on the back of the thermostat. For heat pumps with separate W2 and E wires, label both as W/E and connect to the same terminal.
Push excess wire into the wall and plug the hole with fire-resistant material (e.g., fiberglass insulation) to prevent drafts.
Snap the thermostat onto the base carefully.

Battery Location

Includes 2 AA alkaline batteries with a battery tag to prevent power drainage. Remove the tag to engage batteries.
Replace batteries when the battery icon shows low or before leaving the home unoccupied for over 3 months. Use premium brand AA alkaline batteries (e.g., Duracell or Energizer).
Install batteries in the rear compartment above the battery slot, ensuring correct polarity.

Wiring and Terminal Functions

Thermostat wiring does not follow a standardized color code. Take a picture and label wires before removing the old thermostat. Refer to the equipment manufacturer’s instructions for specific wiring. The following table describes typical terminal functions:

Terminal	Function
RC	Power for cooling (24 VAC)
RH	Power for heating (24 VAC)
C	Common wire, 24 VAC (required for heat only, cool only, or heat pump systems)
Y	1st stage cool (compressor contactor)
Y2/*	2nd stage cool or humidifier (if configured)
W/E	1st stage heat or emergency heat (heat pump)
W2/*	2nd stage heat or dehumidifier (if configured)
G	Indoor blower (fan)
O/B	Heat pump changeover valve (O: cool, B: heat), zone panel, or 3-wire hot water zone valve
L	Heat pump fault indicator or zone panel connection

Note: For single-transformer systems, the thermostat has a built-in RC/RH jumper; no field jumper is needed. For two-transformer systems, clip the RC/RH jumper on the back of the thermostat. For heat pumps, label “B” as “C” only if the old thermostat had a wire on “O”; otherwise, label as “B”. For systems with separate W2 and E wires, label both as W/E and connect to the same terminal. Do not exceed specified voltage ratings.