Carrier THT420A, THT420C, THT420B, THT421A-N

DC Brushless Fan Coil Thermostat User Manual

Models: THT420A, THT420C, THT420B, THT421A-N

1. Producte acabatview

The Carrier DC Brushless Fan Coil Thermostat is designed for precise temperature control in HVAC systems. It features a clear digital display and intuitive controls for managing heating, cooling, and fan operations. This manual provides essential information for installation, operation, and maintenance of your thermostat.

Davant view of the Carrier DC Brushless Fan Coil Thermostat display showing 22.2 degrees Celsius, a snowflake icon for cooling mode, and control buttons.
Figura 1: Frontal view of the Thermostat with display and control buttons.
lateral view of the thermostat base showing a label with model number THT420A and serial number.
Figura 2: lateral view of the Thermostat base with model identification.

2. Instal·lació i cablejat

Proper installation and wiring are crucial for the safe and correct operation of the thermostat. It is recommended that installation be performed by a qualified technician.

2.1 Muntatge

Mount the thermostat in a location that accurately reflects the room temperature, away from direct sunlight, drafts, or heat sources. Ensure the mounting surface is flat and stable.

2.2 Esquema de cablejat

Refer to the diagram below for correct wiring connections. Ensure all power is disconnected before performing any wiring.

posterior view of the thermostat base showing terminal block connections for power, valve outputs, RS485, and 0-10V output.
Figure 3: Wiring Terminals on the Thermostat Base.
Wiring Terminal Descriptions
TerminalDescripció
L, N220VAC Power Input (Live, Neutral)
Co1Cold Valve Normally Open Output
Co2Cold Valve Normally Closed Output
Ho1Hot Valve Normally Open Output
Ho2Hot Valve Normally Closed Output
A, BInterfície de comunicació RS485
VSP, GND0-10V Output for Variable Speed Pump/Fan, Ground

3. Instruccions de funcionament

The thermostat features a user-friendly interface with several control buttons and a clear digital display.

3.1 botons de control

  • Botó d'encendre (): Turns the thermostat ON or OFF.
  • Botó de mode (M): Cycles through operating modes (e.g., Cooling, Heating, Fan Only). The snowflake icon indicates cooling mode.
  • Botó de velocitat del ventilador (): Ajusta la velocitat del ventilador (per exemple, Baixa, Mitjana, Alta, Automàtic).
  • Botó de configuració (): Accesses advanced settings or configuration options.
  • Fletxes amunt/avall (/): Adjusts the set temperature or navigates through menu options.

3.2 Configuració de la temperatura

  1. Ensure the thermostat is powered ON.
  2. Utilitzeu el Up () o avall () arrow buttons to increase or decrease the desired temperature. The display will show the new setpoint.

3.3 Canvi del mode de funcionament

  1. Press the Mode (M) button repeatedly to cycle through available modes.
  2. Common modes include Cooling (indicated by a snowflake icon), Heating, and Fan Only.

4. Manteniment

Regular maintenance helps ensure optimal performance and longevity of your thermostat.

  • Neteja: Gently wipe the thermostat's surface with a soft, dry cloth. Do not use abrasive cleaners or solvents.
  • Comprovació de connexió: Periodically inspect wiring connections to ensure they are secure and free from corrosion. (Only perform if qualified and power is off).
  • Eviteu les obstruccions: Ensure no objects block the thermostat's vents or sensors, as this can affect temperature readings.

5. Solució De Problemes

If you encounter issues with your thermostat, try the following steps before contacting support.

  • Sense alimentació/Pantalla apagada: Check the main power supply to the thermostat. Ensure all wiring connections are secure.
  • Lectura de temperatura incorrecta: Ensure the thermostat is not exposed to direct sunlight, drafts, or heat sources. Clean any dust from the thermostat's exterior.
  • System Not Responding (Heating/Cooling): Verify the operating mode is correctly set. Check if the fan coil unit is receiving power and functioning correctly.
  • El ventilador no funciona: Check fan speed settings. Ensure the fan coil unit's fan motor is operational.

6. Especificacions

Especificacions del producte
CaracterísticaDetall
Números de modelTHT420A, THT420C, THT420B, THT421A-N
Tipus de producteDC Brushless Fan Coil Thermostat, Temperature Control Panel Switch Controller
Entrada de potènciaLN 220VAC
Sortides de vàlvulesCold Valve (NO/NC), Hot Valve (NO/NC)
Sortida analògica0-10V (for Variable Speed Pump/Fan)
ComunicacióRS485
ElèctricNo (refers to internal electric heating element)
Substància química molt preocupantCap
OrigenXina continental
Dimensions del paquet (L x W x H)22 cm x 11 cm x 22 cm
Pes del paquet1.2 kg

7. Consells d'usuari

  • For optimal energy efficiency, set your desired temperature and allow the thermostat to manage the system automatically. Avoid frequent manual adjustments.
  • If integrating with a smart home system, ensure correct RS485 communication protocols are followed as per your system's requirements.
  • Consider the placement of the thermostat carefully during installation to prevent inaccurate temperature readings caused by external factors.

8. Garantia i Suport

For technical assistance, warranty claims, or further inquiries, please contact our support team:

  • WhatsApp: +86 13629613165
  • Correu electrònic: 821401379@qq.com

Please have your model number and any relevant details ready when contacting support to ensure efficient service.

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