Emerson 1F86EZ-0251 Non-Programmable Thermostat installation and operating instruction


Emerson 1F86EZ-0251 Non-Programmable Thermostat

Emerson 1F86EZ-0251 Non-Programmable Thermostat-product

Message to Homeowner

Emerson 1F86EZ-0251 Non-Programmable Thermostat-fig.1

Congratulations on choosing the Emerson Blue Easy Set Thermostat. The Easy Set is designed to be the easiest thermostat you have ever used. This thermostat features Home, Sleep, and Away temperature pre-sets. Just press the button and go. Included with the easy set is the same temperature accuracy and reliability you expect from all the Emerson Blue thermostats.

This thermostat is intended for use with a low-voltage NEC Class II system. Do not use this thermostat with a line voltage system. If in doubt about whether your wiring is millivolt, line, or low voltage, have it inspected by a qualified heating and air conditioning contractor or electrician.
Do not exceed the specification ratings.
All wiring must conform to local and national electrical codes and ordinances.
This control is a precision instrument and should be handled carefully. Rough handling or distorting components could cause the control to malfunction.


Before you begin using your thermostat, you should be familiar with its features and with the display, and the location and operation of the thermostat buttons and switches.

The Thermostat Buttons and Switches

Emerson 1F86EZ-0251 Non-Programmable Thermostat-fig.2

  1. Raises temperature setting.
  2. Lowers temperature setting.
  3. Easy Temperature pre-sets (Home, Sleep, Away).
  4. SYSTEM switch (COOL, OFF, HEAT).
  5. FAN switch (ON, AUTO).
    The Display
  6. Indicates setpoint temperature. This is blank when the system switch is in the OFF position. The setpoint temperature is displayed (flashing) if the thermostat is in lockout mode to prevent the compressor from cycling too quickly.
  7. “Save” indicates the Cool Savings feature is enabled in the configuration menu. “Save” (flashing) indicates Cool Savings feature is active.
  8. The flame icon is displayed when the SYSTEM switch is in the HEAT position. The flame icon Emerson 1F86-0244 Single-Stage Thermostat-fig.9 is displayed flashing when the thermostat is calling for heat. Snowflake icon ( ) is displayed (non-flashing) when the SYSTEM switch is in the COOL position. A snowflake iconEmerson 1F86-0244 Single-Stage Thermostat-fig.9 is displayed(flashing) if the thermostat is calling for cool.
  9. Displays current temperature.
  10. “Service” indicates a diagnostic fault in the heating/cooling system. It does not indicate a fault in the thermostat.
  11. “Change Filter” is displayed when the system has run for the programmed filter time period as a reminder to change or clean your air filter.
  12. Emerson 1F86-0244 Single-Stage Thermostat-fig.3 indicates power level of batteries. “Change Emerson 1F86-0244 Single-Stage Thermostat-fig.4” indicates batteries should be replaced.


Two “AA” alkaline batteries are included with your thermostat. Prior to use, open the battery door and remove the battery tag. We recommend replacing batteries every 2 years, for best results, use new premium brand alkaline batteries such as Duracell® or Energizer®. When battery power remaining is approximately half, the will be displayed.

Emerson 1F86-0244 Single-Stage Thermostat-fig.4Indicates batteries are low and should be replaced.

Emerson 1F86-0244 Single-Stage Thermostat-fig.2

If the home is going to be unoccupied for an extended period (over 3 months) and Emerson 1F86-0244 Single-Stage Thermostat-fig.4is displayed, the batteries should be replaced before leaving. When less than two months of battery life remain, the setpoint temperature will change by 10 degrees (10 degrees cooler in Heat / 10 degrees warmer in Cool) to alert you to change the batteries before they fail. If the temperature change occurs, the normal setpoint can be manually reset. However, the temperature will change by 10 degrees within two days if the batteries are not replaced.

  • Do not use on circuits exceeding specified voltage.
  • Higher voltage will damage control and could cause shock or fire hazards.
  • Do not short out terminals on gas valve or primary control to test. Short or incorrect wiring will damage the thermostat and could cause personal injury and/or property damage.
  • Thermostat installation and all components of the system shall conform to Class II (current limited) circuits per the NEC code. Failure to do so could cause a fire hazard.
  • For California Residents: This product contains a chemical known to the state of California to cause cancer and birth defects and other reproductive harm.


Home, Sleep and Away Temperature Pre-Sets

You can set your (Home, Sleep, Away) temperatures for use when you get home, go to sleep, or leave home. Then, just press the button you want and go.
Favorite Temperatures are set at the factory as indicated in the following table. You can use pre-sets or change to different temperature pre-sets.

Emerson 1F86EZ-0251 Non-Programmable Thermostat-fig.3

Change Home, Sleep and Away Temperature Pre-sets

  1. Move the SYSTEM switch to the HEAT position.
  2. Using the Emerson 1F86-0244 Single-Stage Thermostat-fig.5 button, set the desired temperature.
  3. Press and hold the Home, Sleep, or Away button for 3 seconds. The display will go blank (except for the battery icon and heat/cool icon) and back on again indicating that the thermostat has saved your pre-set.
  4. Repeat the process for the remaining Pre-sets to be changed.
  5. Move the SYSTEM switch to COOL to Pre-set Temperatures for cooling.

Use Home, Sleep and Away Temperature Pre-Sets

  1. Press the Home, Sleep, or Away buttons. The display will show the icon for the button pressed and display the temperature setting.
  2. The thermostat will maintain the selected pre-set temperature until you change it by pressing the Emerson 1F86-0244 Single-Stage Thermostat-fig.5 button or selecting another Pre-set Temperature.

Sleep Timer Option
The sleep timer will automatically change the thermostat from the Sleep to Home temperature after the number of hours set in the configuration menu. The Sleep timer default is 8 hours and can be changed to a setting between 1 to 12 hours.
Example: You have selected 8 hours for the Sleep timer in the configuration menu. Press the Sleep button, the thermostat will maintain the sleep temperature for 8 hours. After 8 hours the thermostat will go back to the Home temperature. The Sleep timer will be activated each time the sleep button is pressed.

Change Filter Reminder Option
The thermostat can display a reminder when it is time to change the air filter on your heating and cooling system. The Change Filter will automatically display after the number of hours set in the configuration menu. The change filter reminder time default is 200 hours and can be changed to a setting of 25 to 1975 hours; 200 hours is approximately 3 months.
Example: You have selected 250 hours for the change filter reminder. The thermostat will display change filter after 250 it has counted down 250 hours. When “Change Filter” is displayed, press the or button to clear the display and restart the timer.

Cool Savings™ Option
With Cool Savings enabled, the thermostat will make small adjustments to the desired temperature during periods of high demand to reduce cooling system running time and save energy. When the cooling system has been running for more than 20 minutes, humidity in the home will be lower and a higher temperature will feel comfortable. After 20 minutes of run time, the thermostat will start increasing the desired temperature in steps of less than one degree as the system continues to run. These adjustments will eventually cause the system to satisfy the thermostat and turn the system off to reduce the energy consumption. When the Cool Savings feature is active and making adjustments, the display will flash “Save”. The amount of adjustments to the desired temperature is dependent on the Cool Savings value that is set, 1 being the least adjustment and 6 being the most adjustment. With this feature set to OFF, no change will occur when the cooling system is continuously running during periods of high demand. Periods of high demand will normally occur during the late afternoon and early evening on the hottest days of the summer.



  1. Shut off electricity at the main fuse box until installation is complete. Ensure that electrical power is disconnected.
  2. Remove the front cover of the old thermostat. With wires still attached, remove wall plate from the wall. If the old thermostat has a wall mounting plate, remove the thermostat and the wall mounting plate as an assembly.
  3. Identify each wire attached to the old thermostat using the labels enclosed with the new thermostat.
  4. Disconnect the wires from old thermostat one at a time. DO NOT LET WIRES FALL BACK INTO THE WALL.
  5. Install new thermostat using the following procedures.

Install the New Thermostat

  1. Open the battery door and detach the new thermostat cover from the base.
  2. With the base flush against the wall, mark mounting hole locations on wall.
  3. Move base out of the way and drill mounting holes.
  4. Push wires through wire opening.
  5. Position the base on the wall again and screw the mounting screws into the wall anchors.
  6. Connect each wire coming from the wall to its corresponding terminal as shown in Fig. 2 thru 4 on page 7.

Emerson 1F86EZ-0251 Non-Programmable Thermostat-fig.4
Wires will not be connected to all terminals of the terminal block.

Emerson 1F86-0244 Single-Stage Thermostat-fig.1

Set Switches

Gas / Elec Switch
If your system is a heat pump, the GAS/ELEC Switch must be set to ELEC (see Fig. 1) If your system is a single stage, the switch must be set to GAS. The switch setting must agree with the system configuration selected in the configuration menu.
O/B Terminal Switch Selection
The O/B switch on this thermostat is factory set to the “O” position. This will accommodate the majority of heat pump applications, which require the changeover relay to be energized in COOL. If the thermostat you are replacing or the heat pump is installed with this thermostat requires a “B” terminal, to energize the changeover relay in HEAT, the O/B switch must be moved to the “B” position.

Check Thermostat Operation

Heating System

  1. Move the SYSTEM switch to the HEAT position. If the heating system has a standing pilot, be sure to light it.
  2. Press to adjust the thermostat setting to 1° above room temperature. The heating system should begin to operate.
  3. Press to adjust the temperature setting below room temperature. The heating system should stop operating.

Fan Operation
If your system does not have a G terminal connection, skip to Heating System.

  1. Move the SYSTEM switch to the OFF position.
  2. Move the fan switch to ON position. The blower should begin to operate.
  3. Move the fan switch to the AUTO position. The blower should stop immediately.

Cooling System

  1. Move the SYSTEM switch to the COOL position.
  2. Press to adjust the thermostat setting below room temperature. The blower should come on immediately on high speed, followed by cold air circulation. However, if the setpoint temperature is flashing, the compressor lockout feature is operating (see Configuration menu, item 5).
  3. Press to adjust the temperature setting above room temperature. The cooling system should stop operating.

Select Configuration Options

The configuration menu allows you to set certain thermostat operating characteristics to your system or personal requirements

Emerson 1F86EZ-0251 Non-Programmable Thermostat-fig.5

Configuration Menu

Menu Screen Number Displayed (Factory Default) Press  or  to select options
01 (SS) HP Select Single Stage (SS) or

Heat Pump (HP) for a single compressor

02 Sleep (OFF) On Select Sleep Timer On or OFF

If selected OFF, skip to menu screen 04

03 h (8) 1 to 12 Select 1 to 12 hours for Sleep Timer On. See Sleep Timer section on page 3
04 CS (OFF) On Select Cool Savings Feature On or OFF If selected OFF, skip to menu screen 06
05 CS (3) 1 to 6 Select 1 to 6 for Cool Savings Feature On See Cool Savings section on page 3
06 CR


FA, SL Select Adjustable Anticipation, cycle rate for Heat See table below
07 CR


FA, SL Select Adjustable Anticipation, cycle rate for Cool See table below
08 CL (OFF) On Select Compressor Lockout OFF or On. When selected On, the thermostat will wait 5 minutes before turning the compressor on.
09 L (On) OFF Select Display Light On or OFF. When selected On and the “C” terminal is connected, the backlight will stay on continuously. When OFF the backlight will come on for a short time when any key is pressed.
10 Room Temp (0) 4 LO to

4 HI

Select room temperature display for 4o higher or 4o lower than the actual temperature
11 oF oC Select oF or oC Display (temperature displayed in Fahrenheit or Celsius)
12 Change Filter (OFF) On Select the filter maintenance indicator OFF or On. If selected OFF, item B will be skipped
13 Change Filter (200 h) 25 to 1975 Select 25 to 1975 hours for the Change Filter reminder See the Change Filter reminder section on page 3

To exit the menu: Set the system switch to Cool or Heat. If no keys are pressed within fifteen minutes, the thermostat will revert to normal operation.

Select Cycle Rate – The cycle rate can be adjusted to keep the heat or cool on longer or shorter to match the temperature response of the home with your heating and cooling system.






SS Heat 0.6oF 0.8oF 1.2oF
SS Cool 1.2oF 1.7oF
HP Heat & Cool 1.2oF 1.7oF


Reset Operation

If a voltage spike or static discharge blanks out the display or causes erratic thermostat operation, you may need to reset the thermostat. To reset, the System Switch must be in Cool or Heat. Simultaneously press Emerson 1F86-0244 Single-Stage Thermostat-fig.5  buttons for approximately 10 seconds until the display goes blank. If the thermostat has power, has been reset and still does not function correctly contact your heating/cooling service person or place of purchase.

Symptom Possible Cause Corrective Action
No Heat/No Cool/No Fan common problems) 1. Blown fuse or tripped circuit breaker.2.  Furnace power switch to OFF.

3. Furnace blower compartment door or panel lose or not properly installed.

Replace the fuse or reset the breaker. Turn the switch to ON.Replace the door panel in the proper position to engage the safety interlock or door switch.
No Heat 1. System Switch not set to Heat.

2.  Loos connection to thermostat or system

3. Heating System requires service or thermostat requires replacement.

Set System Switch to Heat and raise the setpoint above room temperature.Verify thermostat and system wires are securely at- attached.

Diagnostic: Set the System Switch to Heat and raise the set- point above room temperature. Within five minutes the thermostat should make a soft slick sound. This sound usually indicates the thermostat is operating properly.

If the thermostat does not click, try the reset operation listed above. If the thermostat does not click after being reset contact your heating and cooling service person or place of purchase for a replacement. If the thermostat

clicks, contact the furnace manufacturer or a service per- son to verify the heating system is operating correctly.

No Cool 1. System Switch not set to Cool.

2.  Loose connection to thermostat or system.

3. Cooling System requires service or the thermostat requires replacement

Set System Switch to Cool and lower the setpoint below room temperature.Verify thermostat and system wires are securely attached.

Same procedures as diagnostic for No Heat condition except set the thermostat to Cool and lower the setpoint below the room temperature. There may be up to a five-minute delay before the thermostat clicks in Cooling if the compressor lock-out option is selected in the configuration menu (Item 5).

Heat, Cool or Fan Runs Constantly 1. Possible short in the wiring.2. Possible short in thermostat.

3. Possible short in Heat/Cool/Fan system.

4. Fan Switch set to Fan On.

Check each wire connection to verify they are not shorted or touching together. No bare wire should stick out from under terminal screws. Try resetting the thermostat as described below. If the condition persists, the manufacturer of your system or service person can instruct you on how to test the Heat/cooling/ system for correct operation. If the system operates correctly, replace the thermostat.
Furnace Cycles Too Fast or Too Slow Cooling Cycles Too Fast or Too Slow (narrow or wide temperature swing) 1. The location of the thermostat and/or the size of the Heating or Cooling System may be influencing the cycle rate. Item 3 (CR Heat) or 4 (CR Cool) in the Configuration Menu is the adjustment that controls the cycle rate. If an acceptable cycle rate is not achieved using the FA (Fast) or SL (Slow) adjustment contact a local service person for additional suggestions.
Thermostat Setting and Thermometer Disagree 1. Thermostat thermometer setting requires adjustment. The thermometer can be adjusted +/- degrees as listed in item 7 of the Configuration Menu. No other adjustment is possible.
Blank Display and/or Keypad Not Responding 1. Voltage Spike or Static Discharge. If a voltage spike or static discharge occurs use the Reset Operation listed above.


Figure 2. Typical wiring diagram for single transformer single stage systems

Emerson 1F86EZ-0251 Non-Programmable Thermostat-fig.6Figure 3. Typical wiring diagram for two transformer single-stage systems with NO safety circuits Emerson 1F86EZ-0251 Non-Programmable Thermostat-fig.7 Figure 4. Typical wiring diagram for two transformer single-stage systems with safety circuits in BOTH systemsEmerson 1F86EZ-0251 Non-Programmable Thermostat-fig.8


Thermostat Configuration Options Thermostat Applications Maximum Stages Heat/Cool
Single Stage 1 No Heat Pump (SS) Gas, Oil, Electric, Heat Only, Cool Only or Heat

/ Cool Systems



Heat Pump 1 Single Stage Compressor Heat Pump (HP) Single Stage Compres- sor Heat Pump Systems

– with no Aux. Heat



This product does not contain mercury. However, this product may replace a unit that contains mercury.
Do not open mercury cells. If a cell becomes damaged, do not touch any spilled mercury. Wearing nonabsorbent gloves, take up the spilled mercury and place into a container which can be sealed. If a cell becomes damaged, the unit should be discarded.
Mercury must not be discarded in household trash. When the unit this product is replacing is to be discarded, place in a suitable container. Refer to www.thermostat-recycle.org for location to send the product containing mercury.


Electrical Rating:

  • Battery Power: mV to 30 VAC, 50/60 Hz or DC
  • Input-Hardwire:20 to 30 VAC
  • Terminal Load: 1.0 A per terminal, 1.5A maximum all terminals combined
  • Setpoint Range: 45° to 90°F (7° to 32°C)
  • Differential (Single Stage): Heat 0.6°F; Cool 1.2°F (adjustable)
  • Differential (Heat Pump): Heat 1.2°F; Cool 1.2°F (adjustable)
  • Operating Ambient:32° to +105°F (0° to +41°C)
  • Operating Humidity:90% non-condensing max.
  • Shipping Temperature Range: -40° to +150°F (-40° to +65°C)
  • Dimensions Thermostat: 3-3/4” H x 4-3/4” W x 1-1/2” D


Download Manual: Emerson 1F86EZ-0251 Non-Programmable Thermostat installation and operating instruction

Emerson-logo Emerson 1F86EZ-0251 Non-Programmable Thermostat installation and operating instruction


Leave a Reply

Your email address will not be published. Required fields are marked *