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Emerson 1F75H-21NP - Non-Programmable Heat Pump Thermostat Manual

Contents

Thermostat Applications Maximum Stages Heat/Cool
Single Stage Compressor, Heat Pump Systems (air source or geothermal) – 1 Stage Aux/Emergency Heat 2/1

MERCURY NOTICE: This product does not contain mercury. However, this product may replace a product that contains mercury. Mercury and products containing mercury must not be discarded in household trash.
Refer to www.thermostat-recycle.org for information on disposing of products containing mercury.

SPECIFICATIONS

Electrical Rating:
Battery Power 20 to 30 VAC, NEC Class II, 50/60 Hz
Input-Hardwire 20 to 30 VAC, NEC Class II, 50/60 Hz
Terminal Load 1.5 A per terminal, 2.5A maximum all terminals combined
Setpoint Range 45° to 99°F (7° to 37°C)
Rated Differentials (@ 6°F/ Hr): Fast Med Slow
Heat Pump (Heat) 0.9°F 1.2°F 1.7°F
Heat Pump (Cool) 0.9°F 1.2°F 1.7°F
Auxiliary Heat 0.5°F 0.75°F 1.9°F
Operating Ambient 32°F to +105°F (0° to +41°C)
Display Temperature Range 32°F to +99°F (0 to 37°C)
Operating Humidity 90% non-condensing maximum
Shipping Temperature Range -20°F to + 150°F (-29° to +65°C)
Thermostat Dimensions 3-3/4" H x 6" W x 1-1/8" D

THERMOSTAT INSTALLATION

WIRING

Refer to equipment manufacturer's instructions for specific system wiring information. After wiring, see INSTALLER MENU for proper thermostat configuration. Wiring table shown are for typical systems and describe the thermostat terminal functions.

Terminal Designations Terminal Function
R Power (24V)
O/B Changeover Terminal-Energized in Cool (O) or Heat (B) for Heat Pump or Damper Systems
Y Heat and Cool Mode 1st Stage Compressor
G Fan Relay
E* Auxiliary only Heat Mode (Emergency Heat)
C Common wire for 24V (optional with batteries)
W2* Heat Mode – 2nd stage

*Cut W2/E jumper when separate heat sources are used for W2 and E.


For Dual Fuel Heat Pump applications, be sure to turn on the Duel Fuel Logic option (found in the Installer's Menu)

Levelling

Precautions

  • 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 handing or distorting components could cause the control to malfunction.

Do not use on circuits exceeding specified voltage. Higher voltage will damage control and could cause shock or fire hazard.

Do not short out terminals on gas valve or primary control to test. Short or incorrect wiring will burn out thermostat and could cause personal injury and/or property damage.
To prevent electrical shock and/or equipment damage, disconnect electrical power to system at main fuse or circuit breaker box until installation is complete.

Battery Location

  1. W2/E Jumper Wire
    This thermostat electrically connect the W2 and E terminals so that you do not need to do this with a jumper wire. If your system has separate W2 and E wires, clip the W2/E jumper located on the back of the thermostat. This will isolate both terminals so they can be used independently.
  2. O/B Terminal Switch
    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 heat pump being installed requires a B terminal to energise the changeover relay in Heat, the O/B switch must be moved to the B position.

INSTALLER MENU

To access the INSTALLER'S MENU set the system switch to the OFF position and then press and hold the temperature buttons for 3 seconds. The display will show item 30 in the table below. Use the temperature buttons by pressing them simultaneously to navigate through menu items. Press or to change a menu setting.

Installer's Menu #
(Hold Menu 3 Seconds) 		Description Default Setting
(flashing icons) 		Settings
(Press or )
30 Heat Cycle Rate (how often the heat will turn on) MEd

SLO – slow

MEd – medium

FAS – fast
32 Aux Cycle Rate (how often the auxiliary heat will turn on) MEd

SLO – slow

MEd – medium

FAS – fast
35 Cool Cycle Rate (how often the cooling will turn on) MEd

SLO – slow

MEd – medium

FAS – fast
50 Compressor Lockout (protects the compressor from short cycling) OFF

On – 5 minute delay

OFF – no delay
60 Duel Fuel Logic (turn On when using gas as the auxiliary heat source) OFF

On- gas auxiliary heat

OFF- electric auxiliary heat
65 Maximum Heat Limit (maximum set point for heat mode) 99 47 to 99
66 Minimum Cool Limit (minimum set point for cool mode) 45 45 to 97
Installer's Menu #
(Hold Menu 8 Seconds) 		Description Default Setting
(flashing icons) 		Settings
(Press or )
79 Fahrenheit or Celsius °F

°F – Fahrenheit

°C – Celsius
81 Temperature Display Adjustment (adjust the displayed "Room Temperature") 0 -5 to +5
83 Continuous Display Light (keep the backlight always on – "C" wire required) OFF

On – always on

OFF – momentarily

TEST EQUIPMENT

Turn on power to the system.

Fan Operation

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

  1. Move fan switch to On position. The blower should begin to operate.
  2. Move fan switch to Auto position. The blower should stop immediately.

Heating System

  1. Move System Switch to Heat position. If the auxiliary heating system has a standing pilot, be sure to light it.
  2. Press to adjust thermostat setting to 1° above room temperature. The heat pump system should begin to operate and the thermostat will indicate Heat On.
  3. Press to adjust thermostat setting to 3° above room temperature. The auxiliary heat should begin to operate and the thermostat will indicate Heat On Auxiliary.
  4. Press to adjust thermostat setting 1° below room temperature. The heating system should stop operating and the thermostat should indicate Heat.

Auxiliary System

  1. Move System Switch to Aux position. If the auxiliary heating system has a standing pilot, be sure to light it.
  2. Press to adjust thermostat setting to 1° above room temperature. The auxiliary heating system should begin to operate and the thermostat will indicate Heat On Auxiliary.
  3. Press to adjust thermostat setting 1° below room temperature. The auxiliary heating system should stop operating and the thermostat should indicate Heat Auxiliary.

Cooling System

  1. Move System Switch to Cool position.
  2. Press to adjust thermostat setting 1° below room temperature. The blower should come on immediately on high speed, followed by cold air circulation. The thermostat will indicate Cool On. There can be up to a 5 minute delay. (see INSTALLER MENU, item 50)
  3. Press to adjust thermostat setting to 1° above room temperature. The cooling system should stop operating and the thermostat will indicate Cool.

Note: If Starting Soon is shown on the display, the compressor lockout feature is operating. There will be up to a 5 minute delay before the compressor turns on.(see INSTALLER MENU, item 50)

To prevent compressor and/or property damage, if the outdoor temperature is below 50°F, DO NOT operate the cooling system.

Do not allow the compressor to run unless the compressor oil heaters have been operational for 6 hours and the system has not been operational for at least 5 minutes.

USING THE THERMOSTAT

THERMOSTAT OVERVIEW

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

Overview

THERMOSTAT BUTTONS AND SWITCHES THE DISPLAY
  1. Fan Switch
  1. Thermostat is protecting the equipment from short cycling (5-minute delay)
  1. System Switch
  1. Indicates that the system is running in cool, heat or auxiliary mode (The auxiliary will run in Heat mode when the heat pump cannot maintain the set temperature.)
  1. Raises Temperature Setting
  1. Battery status indicator
  1. Lowers Temperature Setting
  1. Low battery indicator
  1. Temperature setpoint
  1. Displays when the thermostat setpoint has reached the maximum or minimum setting.
  1. Room Temperature
  1. SEE TROUBLESHOOTING

Whenever " " appears in the display, new premium brand AA alkaline batteries should be installed. If the house will be unoccupied for an extended period and either " " or " " is displayed, install new batteries before leaving.

TROUBLESHOOTING

Symptom Possible Cause Corrective Action

No Heat/No Cool/No Fan

(common problem)
  1. Blown fuse or tripped circuit breaker
  2. Furnace power switch to OFF
  3. Furnace blower compartment door panel loose or not properly installed
  4. Loose connection to thermostat or system
  1. Replace fuse or reset breaker
  2. Turn switch to ON
  3. Replace door panel in proper position to engage safety interlock or door switch
  4. Tighten Connections

No Heat
  1. System Switch not set to Heat
  2. Loose connection to thermostat or system
  3. Heating System requires service or thermostat requires replacement
 Verify thermostat and system wires are securely attached.
Diagnostic: Set System Switch to Heat and raise the setpoint above room temperature. Within five minutes the thermostat should make a soft click sound and "Heat On" should appear on display. This sound indicates the thermostat is operating properly. If the thermostat does not click, try the reset operation listed after this charting. 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 person 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 thermostat requires replacement
 Verify thermostat and system wires are securely attached.
Diagnostic: Set System Switch to Cool and lower setpoint below room temperature. 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 installer menu. (see INSTALLER MENU, item 50)

Heat, Cool or Fan Runs Constantly

 Possible short in wiring, thermostat, heat, cool or fan system Check each wire connection to verify they are not shorted or touching other wires. Try resetting the thermostat. If the condition persists contact your HVAC service person.

Thermostat Display & Thermometer Disagree

 Thermostat display requires adjustment Display can be adjusted +/-5°. See User Menu item 04

Furnace (Air Conditioner) Cycles Too Fast or Slow

(narrow or wide temperature swing) 		The location of the thermostat and/ or the size of the Heating System may be influencing the cycle rate Digital thermostats provide precise control and cycle faster than older mechanical models. The system turns on and off more frequently, but runs for a shorter time. If you would like to increase cycle time, choose SLO for slow cycle in the Installer menu. (Reference menu items 30 & 35) If an acceptable cycle rate is not achieved, contact your HVAC service person.

"Call for Service" icon appears on displayed
  1. Heating system is not able to heat the space to within 10 degrees of the setpoint within 2 hours
  2. Cooling system is not able to cool the space to within 10 degrees of the setpoint within 2 hours
  3. If "--" is displayed for the Room Temperature, a replacement thermostat is needed
  4. None of the buttons operate on the thermostat
  5. If "Call for Service" is flashing, compressor self diagnostic is detecting an issue with the outdoor unit
  1. See corrective action for "No Heat"
  2. See corrective action for "No Cool"
  3. Replace thermostat
  4. Make sure keypad lockout is not turned on (denoted by icon)
  5. Contact a service person to verify the equipment is operating correctly

Resetting the Thermostat or Thermostat Settings

If the thermostat has good batteries, but has a blank display or does not respond to key presses, the thermostat should be reset by removing the batteries for 2 minutes. This reset will not change the menu settings. If the condition persists after reinstalling the batteries, replace the thermostat.

To conveniently reset only the user settings back to factory defaults, press the temperature and buttons and move the system switch from OFF to HEAT at the same timeand hold until the display goes blank and resets.


This product contains a chemical known to the state of California to cause cancer and birth defects and other reproductive harm.

HOMEOWNER HELP LINE: 1-800-284-2925

Emerson and White-Rodgers are trademarks of Emerson Electric Co.
©2021 Emerson Electric Co.
All rights reserved.

PART NO.37-7842001

emerson.com/white-rodgers

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