Honeywell Home TF243xx-S Series Digital Thermostat

General

The TF243xx-S series digital thermostat is designed for 3-speed fan and modulating valve control in a fan coil system. It supports 2-pipe cooling only/heating only/manual changeover, ventilation mode, manual or automatic 3-speed fan control, and modulating water valve control.

Key features include a Random Start-up Function to maintain power grid stability and a Honeywell Home Memorized Time Off Function to automatically turn off the thermostat and save energy.

Features

• Memorized time off
• Random startup
• Remote temperature sensor optional
• Energy saving mode optional
• LCD display with simple user interface
• Room temperature or setpoint temperature display selectable
• Manual or automatic fan speed selectable
• Temperature units in either °C or °F
• User setting can be stored when power loss
• Freeze protection function available
• Keypad lock options
• Heating and cooling setpoint limitation

Specifications

• Power supply: 24(±10%) VAC, 50/60Hz
• Modulating Output: DC 0~10V
• Accuracy: ±1°C at 21°C
• Auto Cycle times: 100,000 times
• Manual Cycle times: 10,000 times
• Protection class: IP20
• Set point range: 10~32°C
• Display range: 0~37°C
• Ambient operating limits: 0~+49°C
• Ambient storage limits: -30~+60°C
• Humidity limits: 5~90% RH, non-condensing
• Remote temperature sensor: NTC20K
• Action Type: 1
• Pollution Degree: 2
• Protection against electric shock class: Class II
• Electronic control software class: Class A
• Rated Impulse Voltage: 4000V
• Maximum Temperature: 155°C
• Relay wiring:
• Wire Sectional area (Recommendation): 1.0~1.5mm²
• Applied altitude up to 2000m above sea level Rating Capacity:
• Working current for the whole product:
• For Fan current: 4(2)A
• 4A: When the load of the thermostat is resistance
• 2A: When the load of the thermostat is inductance
• For valve control signal: 0-10V 16mA Max

Model Selection

Thermostat appearance

The thermostat features an LCD display showing current temperature, setpoint, operating mode, and fan speed. It includes buttons for navigating menus, adjusting settings, and controlling functions like Time-off, Energy Saving Mode, Keypad Lockout, Freeze Protection, and Installation Setup.

LCD display elements:

• Setup Index
• Test Index
• Time-off
• Energy Saving Mode
• Keypad Lockout
• Freeze Protection
• Installation Setup
• Temperature Display
• System Off
• Operating Mode
• Fan Speed
• Setpoint Index

Function

Valve Control

The thermostat measures room temperature via an integrated or remote sensor and maintains the setpoint by delivering modulating valve control command outputs. The fan can be set to manual or automatic 3-speed operation. In manual mode, fan speed is controlled via output F3 (high), F2 (Medium), F1 (Low). In automatic mode, fan speed depends on the modulating duty cycle. When the modulating duty cycle reaches 0%, the valve and fan close.

Memorized Time Off

The time off feature automatically turns off the thermostat after a selectable amount of time. To change the time setting, press and hold the power button for more than 3 seconds and use the "up" and "down" buttons to adjust the value. The setting range is from 0 to 12 hours, with a default of 0.

Energy Saving Mode

Energy saving mode can be activated by a dry contact (e.g., hotel card) or by pressing and holding the "mode" button for more than 3 seconds. When activated by a dry contact, only the multi-key for ISU is accessible. Button presses in this mode will stop energy saving. The setpoint adjusts to a remote setback heating/cooling setpoint. Heating setpoint range: 10°C to 21°C (default 18°C). Cooling setpoint range: 22°C to 32°C (default 26°C).

Backlight

The backlight turns on when any key is pressed and times out 8 seconds after the last key press. In ISU and Installation test mode, the backlight times out after 60 seconds.

Keypad Lockout

Keypad lockout can be configured in ISU. Options include: "All keys are available" (default), "System button locked out", "Fan and system buttons locked out", "All buttons (except power button) locked out", and "All buttons are locked".

Temperature Display

The displayed temperature can be set to show either room temperature or setpoint. This setting can be changed during the ISU (Installation Set Up) process.

Operating Mode

Comfort Mode

In comfort mode, the setpoint and fan speed can be adjusted using the corresponding buttons. This mode supports 2-pipe cooling only, heating only, and manual changeover configurations.

Ventilation Mode

Pressing the "mode" button enters "ventilation" mode. In this mode, the valve remains inactive, and the fan operates at the selected fan speed.

Freeze Protection Mode

Freeze protection can be enabled or disabled in ISU (default is enabled). In heating applications, if the thermostat is off and the temperature drops below 6°C, it will activate heating until the temperature reaches 8°C.

Installation and Wiring

The TF243xx-S Series can be installed in a minimum 71x71x35mm junction box. Ensure screws are locked tightly to prevent wire breakage. Avoid tangling wires between the front case and back case.

Wiring diagram

The diagram shows connections for 24VAC power supply, hotel card, remote sensor, modulating valve, and fan. Terminals include R, C, RS, VO, F3, F2, F1, and L.

Terminal Designations

Note: The 24Vac power supply should meet Class 2 SELV and be less than 100VA. A fuse or breaker is necessary before the L terminal (Fuse range: 5.0 A to 6.3A).

ISU (Installation Setup)

To enter or exit ISU, press and hold the "mode" and "up" buttons together for more than 3 seconds. Change the ISU code by pressing the "mode" button, and then change the option setting by pressing the "up" and "down" buttons.

ISU Codes and Options:

Subject to change without notice.