Honeywell Communicating Fan Coil Thermostat

Honeywell Communicating Fan Coil Thermostat featured


The TF428WNM/U communicating thermostat is designed for 3-speed fan and valve control in fan coil system, including:

  • 2-pipe cooling only/heating only/manual changeover
  • 4-pipe cooling/heating manual/automatic changeover
  • Ventilation mode
  • Manual or automatic 3-speed fan control
  • Water valve on/off control

The TF428WNM/U is available in Modbus RTU protocol and can be easily integrated into building automation system.


  • RS485 interface in Modbus RTU slave mode
  • Memorized time off
  • Cycle Per Hour (CPH)
  • Random startup
  • 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


Physical Layer                        EIA485
Protocol                                Modbus RTU
Baud rate                              4800/9600(Default)/19200
Parity                                     None
Error checking mechanism    CRC
Rated voltage & Frequency    220/230VAC, 50/60Hz
Power consumption              <2W
Control                                 PI, On/off output
Accuracy                              ±1°C at 21°C
Auto cycle times                   100,000 times
Manual cycle times                10,000 times
Protection class                     IP20
Setpoint 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
Action Type:                           1
Pollution Degree                     2
Protection against electric shock class Class II
Electronic control software class Class A
Rated impulse voltage: 2500V
Maximum temperature
For relay wiring
Wire sectional area
Applied altitude up to 2000m above sea level

Rating capacity
Working current for the whole product : 4(3)A
4A: When the load of the thermostat is resistance
3A: When the load of the thermostat is inductance

For Fan load 3(2)A
3A:when the load is resistance;
2A:When the load is inductance

For Valve load 2(1)A
2A: when the load is resistance;
1A: when the load is inductance
The valve need have overtravel-limit organ to turn off the load.

Model Selection

Model NumberBacklightApplicationPower SupplyVentilation ModePackage
TF428WNM/UWhite2-pipe/4-pipe FCU application220/230Vac;50/60HzYUnit Package

Product Design

Thermostat appearance

Honeywell Communicating Fan Coil Thermostat fig1

LCD display

Honeywell Communicating Fan Coil Thermostat fig2

Dimensions (mm)

Honeywell Communicating Fan Coil Thermostat fig3


Valve Control
Thermostat measures the room temperature via integrated sensor and maintains the setpoint by delivering on/off valve control command output. The fan setting can be selected as manual or automatic 3-speed operation. When in “manual” mode, the fan is switched to the selected speed via control output FH (high), FM (Medium) , FL (Low).
When in “auto“ mode, fan speed depends on the difference between room temperature and setpoint. When room temperature reaches the setpoint, the valve will be closed, and the fan will be closed in the meanwhile.

Honeywell Communicating Fan Coil Thermostat fig4
Honeywell Communicating Fan Coil Thermostat fig5

Memorized Time Off
The time off feature will automatically turn 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 press “up” and “down” button to change the value when the thermostat is working .
NOTE: The setting range is from 0 to 12 hours. The step is 1 hour and the default value is 0.

To turn on the backlight, press any key. The backlight will timeout 8 seconds after the last key is pressed. When in ISU or Installation test mode, the backlight will timeout 60 seconds after the last key is pressed.

Keypad Lockout
Keypad lockout can be set in ISU or over Modbus. The default status is “all keys available”. Keypad lock function can be se-lected as “mode button locked out”, “Fan and mode buttons locked out”, “all buttons (except power button) locked out” and “all buttons locked out”.

Temperature Display
The displayed temperature can be set to room temperature or setpoint. The setting can be changed during ISU (Installation Set Up) process.

Cycle Per Hour (CPH)
CPH function enables the thermostat to open the valve several times per hour as the room temperature approaches to the sepoint.
The value can be changed in the ISU, the default values are 4 for heating and 3 for cooling.

Operating Mode

Honeywell Communicating Fan Coil Thermostat fig6

Comfort Mode
In comfort mode, the setpoint and fan speed can be changed by pressing corresponding buttons. Comfort mode including 2-pipe cooling only/heating only/manual changeover and 4-pipe manual /auto changeover applications.

Honeywell Communicating Fan Coil Thermostat fig7
Honeywell Communicating Fan Coil Thermostat fig8

Ventilation Mode
Press “mode” button to enter “ventilation” mode. In “ventilation” mode, no output for valve while the fan will operate at selected fan speed.Freeze Protection Mode
Freeze protection can be selected as disabled or enabled
(default) in the ISU or over Modbus. In freeze protection mode when thermostat is off and the temperature is below 6°C , the thermostat will activate heating mode until the temperature rises to 8°C .

Installation and Wiring

TF428WNM/U can be installed in standard 86 size junction box directly.

The screws must be locked tightly to avoid wire break off from the terminals. The temperature of mounting box and wall should be in the operating temperature range.

Honeywell Communicating Fan Coil Thermostat fig9

Wiring Diagram

2- pipe application

Honeywell Communicating Fan Coil Thermostat fig10
Honeywell Communicating Fan Coil Thermostat fig11

Honeywell VC4013/VN4013/VS4016 Wiring
Honeywell VC6013/VN6013 Wiring

4-pipe application

Honeywell Communicating Fan Coil Thermostat fig12

Honeywell VC4013/VN4013/VS4016 Wiring
Note: when in 4-pipe application, the thermostat can not be connected with Honeywell VC6013/VN6013 series motorized valve

Terminal Designations

D-Modbus 485-
D+Modbus 485+
FLLow speed fan
FMMedium speed fan
FHHigh speed fan
 V22-pipe application_VC6013: valve close4-pipe application_VC4013: cooling valve open
 V12-pipe application_VC4013/VC6013:valve open4-pipe application_VC4013: heating valve open
LLive wire
NNeutral wire

ISU (Installation Setup)
Press and hold the “mode” and “up” buttons together for more than 3 seconds to enter or exit ISU. Change the ISU code by pressing the “mode” button and then change the option setting by pressing the “up” and “down” button refer to the following introduction.

0Modbus Address1~64    1(Default)
   1   System Type0 Heating only
1 Cooling only
2 Two pipes heating/cooling manual (Default)
4 Fur pipes manual
5 Four pipes auto
 2 Temp. Scale0 °F
1 °C (Default)
  3  Fan Control Type0 Auto only
1 Manual only (3 speed: Low→Med→High→Low)
2 Users can choose auto or manual (Default)
   4  Switching Differen- tial for 4 pipe Auto Changeover With Single Setpoint1ºC (2ºF)
1.5ºC (3ºF)(Default)
2ºC (4ºF)
3ºC (5ºF)
5CPH (Heat)1~12    4(Default)
6CPH (Cool)1~6      3(Default)
7Display Temp. Adjustment-2~2°C, 0.5°C. Default 0°C(-4~4°F, 1°F. Default 0°F)
 8 Temp. Display0 Room temp. (Default)
1 Setpoint
9Heating Range Stops10~32°C.  Default 32°C(50~90°F. Default 90°F)
10Cooling Range stops10~32°C   Default 10°C(50~90°F. Default 50°F)
     11     Keypad Lockout0 All keys are available (Default)
1 Mode button locked out
2 Fan and mode buttons locked out
3 All buttons locked out ex- cept power button
4 All buttons are locked
 12 Freeze Protection0 Disabled
1 Enabled (Default)
 13Power Recovery Status0 OFF
1 Previous status (Default)
 14  Modbus Baud Rate0 9600( Default)
1 4800
2 19200

Modbus Address Table

When the thermostat is integrated into building automation system. Please make configuration refer below list.

Address RegistersParametersProperties and ValueProperties
01Power Switch0-Off;1-OnR/W
02Room TemperatureRoom temperature valueR
03Temp. Scale0-°F;1-°CR/W
04SetpointSet temperature valueR/W
05Fan Speed0-Auto;1-Low speed;2-Med speed;3-High speedR/W
06System Mode0-Ventilation;1-Heating;2-Cooling;3-AutoR/W
07V1 Valve Status0-Closed;1-OpenR
08V2 Valve Status0-Closed;1-OpenR
09Error Code0-None;1-Sensor; 2-EEprom;3-Sensor+ EEpromR
10Fan Status0-Off 1-Low 2-Med 3-HighR
11Modbus Address1~64 1(Default)R/W
12System Type0-Heating only;1-Cooling only;2-Two pipesheating/cooling manual (Default) 4-Four pipes manual;5-Four pipes autoR/W
13Fan Control Type0-Auto;1-Manual;2-Auto+Manual (Default)R/W
14Switching Differential For 4 pipe Auto Changeover With Single Setpoint2-1ºC(2ºF); 3-1.5ºC(3ºF); 4-2ºC(4ºF); 5-3ºC(5ºF);R/W
15CPH (Heat)1-12 4 (Default)R/W
16CPH (Cool)1-6 3 (Default)R/W
17Display Temp. Adjustment0~8(-2~2⁰C) step1(0.5⁰C) 4 (Default) 0~8(-4~4⁰F) step1(1⁰F) 4 (Default)R/W
18Temp. Display0– Room temp. (Default);1-SetpointR/W
19Heating Range Stops100~320 (10~32⁰C)  step5(0.5⁰C) 320 (Default)500~900(50~90⁰F)  step10(1⁰F) 900 (DefaultR/W
20Cooling Range Stops100~320 (10~32⁰C) step5(0.5⁰C)100 (Default500~900(50~90⁰F) step10(1⁰F) 500 (DefaultR/W
Address RegistersParametersProperties and ValueProperties
21Keypad Lockout0- All keys are available (Default);1– Mode but- ton locked out;2- Fan and mode buttons locked out;3- All buttons locked out except power but-ton;4- All buttons locked outR/W
22Freeze Protection0- Disabled;1- Enabled (Default)R/W
23Power Recovery Status0- OFF;1-Previous Status (Default)R/W
24Modbus Baud Rate0-9600 (Default);1-4800;2-19200R/W
25Time Off Time0~12 Step 1 Unit :hR/W
26Remain Time To Turn OffRemain time to turn offR

Note: 1 The parameters are registers,16 bit integer. Modbus Function is 0x01(read),0x06(write sin-gle),0x10(write multiple). 2 Max. 31 devices in one network.

Automation and Control Solutions
Honeywell Environmental and Combustion Controls (Tian Jin) Co., Ltd No. 158, NanHai Road
Tianjin Economic-Technological Development Area
Tianjin, 300457, P.R.C.
Subject to change without notice.

Documents / Resources

Honeywell Communicating Fan Coil Thermostat [pdf] Instruction Manual
Honeywell, Communicating, Fan Coil, Thermostat, TF428WNM, TF428WNU

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