Honeywell Home TF428WNM/U Communicating Thermostat User Manual
Honeywell Home TF428WNM/U Communicating Thermostat

Operating Your Thermostat

power on off Power on/Off
Time OFF Time OFF

  • Presspower on off to switch on/off thermostat. When in off mode, “OFF” icon will display.
  • PressTime OFF could set the automatical turn off time when the thermostat is working. PressTime OFF and hold for more than 3s. After timer icon flashes, press or to set turn off time, then press 0 button to save and exit.
Temperature Setting

In or or mode, press or to set the target room temperature.

Operating Mode
  • Ventilation
  • Heating
  • Cooling
  • Auto

Fan Speed



Trouble Shooting Tips

If…. Then….
Doesn’t work ·   Set the mode to(heating mode) by press

·   Make sure the temperature is set above the room temperature.

·   Make sure shows on the display.

·   Wait 5 minutes for the system to respond.

Doesn’t work ·   Set the mode to :i: (cooling mode) by press.

. Make sure the temperature is set below the room temperature.

·  Make sure  shows on the display.

·  Wait 5 minutes for the system to respond.

Doesn’t work ·  Make sure keypad is unlocked.

·  Check the thermostat is on.

Doesn’t work ·   Make sure keypad is unlocked.

– Make sure the system isn’t in mode.

·   Check the thermostat is on.    —

The system turns off automatically .Make sure the memorized turn off time value isn’t set to Ir.
Display ·   Check the Modbus address and Baud rate, use master to read registers.

·   Check the wiring.

4 Pipes Valve doesn’t work -Check 151J setup.

·                  Check the wiring.

Installation Guide

Must be installed by a trained and experienced installer

Read instruction carefully. Failure to follow instruction will damage the product or cause a hazardous condition.

Caution: ELECTRICAL HAZARD can cause electrical shock or equipment damage. Disconnect power before installation, reparation and detachment.

Installation Tips

TF428WNM/U is designed for standard 75x75x50mm wall mounting box . Install the thermostat about 5 feet (1.5m) above the floor in an area with good air circulation at average temperature.
Installation Tips

Do not install in locations where the thermostat can be affected by:

  • Dead spots behind doors and in corners
  • Not or cold air from ducts
  • Sunlight or radiant heat from appliances
  • Concealed pipes or chimneys
Wiring and Installation

The screw must be locked tightly to avoid wire break off from the terminal. The wire should not be tangled and stucked between front case assembly and back case.

Request Shielded Twisted Pair(STP) wire for R5485 communication. Separate the low voltage and high voltage wiring. Max 32 pcs in one loop, do not connect to unauthorized devices. Select proper terminal resistor based on application environment.

Wiring and Installation

Modbus Requirements

Physical layer EIA485
Protocol Master-Slave
Baud rate 9600 (Default) /4800/19200
Parity None
Signal Transmission RTU
Error Checking Mechanism CRC

Terminal Designations

Terminal Symbol Description
1 D- Modbus 485-
2 D+ Modbus 485+
3 FL Low speed fan
4 EM Medium speed fan
5 FH High speed fan
6 V2 2-pipe-VC6013:Valve close 4-pipe-VC4013:Cooling Vavle open
7 v1 2-pipe-VC4013NC6013:Valve open 4-pipe-VC4013:Heating Vavle open
8 L Live wire
9 N Neutral wire

The temperature of mounting box and wall should be in the operating temperature range.

VC401 3/VN401 3NS401 6 Wiring (2-pipe) 

VC6013/VN6013 Wiring(2 pipe)

VC4013/VN4013VS4016 Wiring(4 pipe)


Enter or exit Installation Setup Mode

ISU Code Description Options
0 Modbus Address 1-64 1(Default)
1 System Type 0-Heat only
1-Cool only
2-2-pipe manual (Default)
4-4-pipe manual
5-4-pipe auto change over
2 Temperature Scale 0-°F 1-°C (Default)
3 Fan Control Type 0-Auto only
1-Manual only (3 speed: Low –,Med->High-.Low)
2-Users can choose auto or cycle (Default)
4 Switching Differential For 4-pipe Auto Changeover Eith Single Set point 1°C (2°F)
1.5°C (3°F) (Default)
2°C (4°F)
3°C (5°F)
5 CPH Value (Heat) 1-12 4(Default)
6 CPH Value (Cool) 1-6 3(Default)
7 Display Temperature Adjustment -2-2°C, Step 0.5°C 0°C (Default) ( -4-4° F, Step 1°F 0°F (Default))
8 Temperature Display 0-Room temperature (Default)
9 Heating Range Stops 10-32 °C32 °C (Default) (50-90 °F 90 °F (Default))
10 Cooling Range Stops 10-32 °C 10 °C (Default) (5090°F 50 °F (Default))
11 Keypad Lockout 0-All keys are available (Default)
1-System button is locked
2-Fan and System button are locked
3-All buttons are locked except power button
4-All buttons are locked
12 Freeze Protection 0-Disable       1Enable (Default)
13 Power Recovery Status 0-OFF 1-Previous status (Default)
14 Modbus Baud rate 0-Baudrate 9600 (Default)
1-Baudrate 4800
2-Baudrate 19200

NOTE: When the thermostats are integrated into building automation system, user is able to change the setting value above in “Communicating Parameter Setting” list as well.

Communicating Parameter Setting

When the thermostat is integrated into building automation system, you can make configuration refer below list.

Addr Configuration Parameters Significance and adjustment Properties
1 Power 0-OFF; 1-ON R/W
2 Room Temp Room temperature R
3 Temperature Scale 0-°F; 1-°C R/W
4 Setpoint Setpoint R/W
5 Fan S peed 0-Auto; 1-Low speed; 2-Med speed; 3-High speed RNV
6 System Mode 0-Ventilation; 1-Heat; 2-Cool; 3-Auto R/W
7 V1 Valve Status 0-Closed; 1-Open R
8 V2 Valve Status 0-Closed; 1-Open R
9 Error Code 0-None; 1-Sensor; 2-EEprom; 3-Sensor+EEprom R
10 Fan Operation Status 0-Off; 1-Low speed; 2-Med speed: 3-High speed R
25 Time Off Time 0-12; Unit: hour RAN
26 Remain Time To Turn Off 0-12; Unit: hour R
Internal settings (User is able to change the setting value of below parameters on site, see details in “ISU” part)
11 Address 1-64 1 (Default) R/W
12 System Type 0-Heat only; 1-Cool only; 2-2-pipe heating/cooling manual(Default);4-4-pipe manual; 5-4-pipe Auto changeover R/W
13 Fan Control Type 0-Auto; 1-Manual; 2-Auto+Manual (Default) RAN/
14 Switching Differential For 4-Pipe Auto Change Over With Single Setpoint 2-1°C (2°F); 3-1.5 °C (3°F) (Default); 4-2°C (4°F); 5-3°C (5°F) RNV
15 CPH Valve For Heat 1-12 4 (Default) R/W
16 CPH Valve For Cool 1-6       3 (Default) R/W
17 Dis play Temp . Adjustment 0-8 ( -2-2°C ) Step 1 (0.5°C)           4 (Default)

0-8 ( -4-4°F ) Step 1 (1°F) 4 (Default)

18 Temp. Display 0-Room Temp.(Default);        1-Setpoint R/W
19 Heating Range Stops 100-320 (10-32°C) Step 5 (0.5°C) 320 (Default) (50-90°F) Step 10 (1°F) 900 (Default) R/W  
20 Cooling Range Stops 100-320 (10-32°C) Step 5 (0.5°C) 100 (Default) 500-900 (50-90°F) Step 10 (1°F) 500 (Default) Fuw
21 Keypad Lockout 0-All Keys are available (Default) R/W
1-System button locked
2-Fan and system button locked
3-All button locked except power button
4-All button are locked
22 Freeze Protection 0-Disable;         1-Enable (Default) R/W
23 Power Recovery Status 0-OFF; 1-Previous status (Default) R/W
24 Modbus Baudrate 0-9600 (Default);       1- 4800; 2-19200 R/W


Documents / Resources

Honeywell Home TF428WNM/U Communicating Thermostat [pdf] User Manual
TF428WNM U Communicating Thermostat, TF428WNM u, Communicating Thermostat

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