Emerson 1F75H-21NP Thermostat Operation Manual

The Emerson 1F75H-21NP is a 70 Series Non-Programmable Thermostat designed for heat pump systems (2H/1C) and conventional single-stage systems. It features a modern design with a backlit display, easy installation, and precise temperature control (±1°F accuracy). Below are the key specifications and operation instructions.

1. Key Specifications 2. Operation Instructions 2.1. Initial Setup 2.2. Operating the Thermostat 2.3. Temperature Display Adjustment 2.4. Troubleshooting 3. Installation Instructions 3.1. Remove Old Thermostat 3.2. Installing New Thermostat 3.3. Battery Location 3.4. Power Stealing Switches

Key Specifications

Type: Non-programmable thermostat
Compatibility:
- Heat pump systems (2H/1C, air source or geothermal, with 1 stage auxiliary/emergency heat)
- Conventional single-stage systems (gas, oil, electric, millivolt, 24V)
- Not compatible with standard heat-only systems, millivolt heat-only systems, standard central air conditioning, or systems exceeding 30 VAC
Power Source:
- Battery: 20-30 VAC, NEC Class II, 50/60 Hz (2 AA alkaline batteries, Duracell or Energizer recommended)
- Hardwired: 20-30 VAC, NEC Class II, 50/60 Hz with common (C) wire
- Power Stealing Assist for systems without C wire
Electrical Rating:
- Terminal Load: 1.0 A per terminal, 1.5 A max combined
- Rated Differentials (@ 6°F/Hr):
  - Heat Pump (Heat): Fast 0.9°F, Medium 1.2°F, Slow 1.7°F
  - Heat Pump (Cool): Fast 0.9°F, Medium 1.2°F, Slow 1.7°F
  - Auxiliary Heat: Fast 0.5°F, Medium 0.75°F, Slow 1.9°F
- Setpoint Range: 45°F to 99°F (7°C to 37°C)
Display: Backlit LCD display, adjustable ±5°F
Operating Conditions:
- Ambient: 32°F to 105°F (0°C to 41°C)
- Humidity: 90% non-condensing max
- Shipping: -20°F to 150°F (-29°C to 65°C)
Dimensions: 3-3/4” H x 6” W x 1-1/8” D
Features:
- Backlit display with large, easy-to-read temperature
- Adjustable temperature display calibration
- Compressor protection (up to 5-minute delay)
- Built-in level and universal backplate for easy installation
- Compatible with 80 Series and Sensi thermostats for upgrades
Thermostat Configuration Options:
- Single Stage Compressor, Heat Pump Systems (air source or geothermal) – 1 Stage Aux/Emergency Heat - Maximum Stages Heat/Cool: 2/1
- Conventional Single-Stage Gas, Oil, Electric (mV and 24V) - Maximum Stages Heat/Cool: 1/1

Operation Instructions

Initial Setup

1. Insert Batteries: Install 2 AA alkaline batteries in the rear compartment, removing the battery tag to activate. Replace when “LO BATTERY” appears (approximately every 2 years).
2. Power On: If hardwired, ensure 20-30 VAC is supplied via the C terminal. The display should show the home screen with temperature and system status.
3. Configure System:

Press and hold MENU for 8 seconds to access INSTALLER MENU (item 30).
Select system type (Conventional or Heat Pump), heat cycle rate (Fast, Medium, Slow), compressor delay (item 50), and O/B setting for heat pumps (O: cool, B: heat).
Exit by pressing RUN or waiting for the display to return to normal.

Operating the Thermostat

1. Select Mode: Press SYSTEM to choose HEAT, COOL, AUTO, AUX (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 with heating/cooling) or ON (continuous).
4. Verify Operation:

In HEAT mode, set temperature 1°F above room temperature; “Heat On” should display, and the heat pump should start.
In COOL mode, set temperature 1°F below room temperature; “Cool On” should display after up to a 5-minute compressor delay (indicated by flashing snowflake icon).
In AUX mode, set temperature 3°F above room temperature; “Heat On Auxiliary” should display, and auxiliary heat should start.

Temperature Display Adjustment

1. Press MENU to access USER MENU.
2. Use NEXT to navigate to Thermometer Adjustment (item 07).
3. Press up/down arrows to adjust the displayed temperature by ±5°F to match the actual room temperature.
4. Press RUN to save and exit.
Note: Use a separate thermometer for calibration. Relocate the thermostat if near drafts, heat sources, or exterior walls (recommended placement: 1.5 meters above the floor, in a frequently used room like the living room or kitchen, not in direct sunlight or on an outside wall).

Troubleshooting

No Display: Check battery polarity or replace with fresh AA alkaline batteries. Verify C wire connection for hardwired setups. Reset by removing batteries for 2 minutes or pressing MENU and Back simultaneously until the display blanks. If the display remains blank, check for loose wiring or a blown fuse.
No Heat/Cool: Ensure SYSTEM is set to HEAT/COOL/AUX, setpoint is above/below room temperature, and circuit breaker is on. Check for compressor delay (up to 5 minutes, indicated by flashing snowflake icon). Verify wiring, especially O/B for heat pumps. If no response, bypass thermostat by connecting R, G, and Y wires to test system; if the system works, replace the thermostat. Contact a professional technician at 1-800-284-2925 if needed.
Furnace Cycles Too Often: In INSTALLER MENU (item 30), adjust heat cycle rate to MEDIUM or SLOW to reduce cycling frequency.
Inaccurate Temperature: Calibrate in USER MENU (item 07, ±5°F). Ensure thermostat is not near drafts, heat sources, or exterior walls. If temperature rises in COOL mode, verify the outdoor unit is running and not obstructed; check filters, vents, and ductwork for blockages.
Fan Runs Continuously: Set FAN to AUTO. If the fan persists, check wiring for shorts in the G terminal. Ensure SYSTEM is not in AUTO mode if only heating or cooling is desired.
Erratic Operation: Reset by removing batteries for 2 minutes or pressing MENU and Back simultaneously. If issues persist, contact a professional technician.

Installation Instructions

Warning: Thermostat installation and all components of the control system shall conform to Class II circuits per the NEC code. To prevent electrical shock or equipment damage, disconnect power at the main fuse or circuit breaker before installation. If replacing a thermostat containing mercury, do not discard in household trash; follow local disposal regulations.

Remove Old Thermostat

Before removing wires, mark wires for terminal identification to ensure proper connections to the new thermostat. Take a picture of the wiring for reference. If the old thermostat contains mercury, wear non-absorbent gloves, clean up any spilled mercury, and place in a sealed container for proper disposal.

Installing New Thermostat

Pull the thermostat body off the thermostat 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, drill mounting holes. Use plastic screw anchors if existing holes are too large.
Fasten base snugly to the wall using mounting holes and two mounting screws. Leveling is for appearance only and does not affect operation.
Connect wires to the terminal block on the base using the appropriate wiring schematic. For single-transformer systems, the RC/RH terminals are connected; clip the jumper for two-transformer systems. For heat pumps, ensure W2 and E wires are properly labeled and connected (clip W2/E jumper if separate).
Push excess wire into the wall and plug the hole with fire-resistant material (e.g., fiberglass insulation) to prevent drafts.
Carefully line the thermostat up with the base and snap into place.

Battery Location

Includes 2 AA alkaline batteries at the factory with a battery tag to prevent power drainage. Remove the tag to engage batteries.
To replace, set system to OFF, remove thermostat from the wall, and install batteries in the rear along the top. Use premium brand AA alkaline batteries like Duracell or Energizer.
If the home will be unoccupied for over 3 months and the battery level indicator shows low, replace batteries before leaving.

Power Stealing Switches

Leave switches in the “On” position for most systems. Details in the following table:

Thermostat Power Method	Switch Position/Description
Battery Powered, no 24 Volt system	Switches “On”, thermostat runs on batteries.
Hardwired with Battery Back-up, for 24 Volt systems with common connection from transformer to “C” terminal	Switches “On”, thermostat runs on power directly from transformer with battery back-up.
Battery Powered with Power Stealing Assist, for 24 Volt systems with no common connection	Switches “On”, thermostat runs on batteries and supplemental power drawn through heat or cool circuit.

Caution: Power Stealing Assist may cause issues on systems with high impedance electronic modules (e.g., furnace draft inducer motor running with no call for heat, furnace fan not turning off). If incompatible, set switches to “Off” to operate on batteries.