Chiltrix CX34 CX35 CX50
Controls Chiltrix CX34, CX35 and CX50 heat pumps via Modbus RTU
This template connects Chiltrix CX34, CX35 and CX50 air-to-water heat pumps to ModbusCloud via Modbus RTU. It reads sensor data such as water temperatures, compressor frequency and water flow, and provides control over on/off switching, operating mode and target temperatures.
- Protocol
- Modbus RTU
- Connection
- RS485, 9600 baud
- Registers
- 13, read and write
- Brand
- Chiltrix
- Key readings
- Ambient Air Temp · Outlet Water Temp · Inlet Water Temp · Compressor Frequency · Water Flow · Input AC Current
- Available commands
- Switch on/off · Operating Mode · AC Cooling Target Temp · AC Heating Target Temp
- Compatible models
- CX34 · CX35 · CX50
- Last updated
Registers (13)
13 read, 4 write
| Name | Unit | Access | Address (Hidden until you enter your email) | Function (hidden) | Type (hidden) |
|---|---|---|---|---|---|
| Switch on/off | Read and write | ||||
| Operating Mode | Read and write | ||||
| AC cooling target temperature | °F | Read and write | |||
| AC heating target temprerature | °F | Read and write | |||
| Hot water target temperature | °F | Read | |||
| AC heating Au mode | Read | ||||
| Hot water Au mode | Read | ||||
| Ambient Air Temp | °F | Read | |||
| Compressor Frequency | Hz | Read | |||
| Outlet water Temp | °F | Read | |||
| Water Flow | gpm | Read | |||
| Input Ac Current | A | Read | |||
| Inlet Water Temp | °F | Read |
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Use cases
- Monitor outlet and inlet water temperatures on a live dashboard to verify heat pump performance remotely.
- Create an alert when compressor frequency or input AC current exceeds a predefined threshold for early fault detection.
- Log water flow and temperature data over time to generate seasonal COP estimates for energy reporting.
- Switch the Chiltrix heat pump on or off remotely during commissioning or scheduled maintenance windows.
- Adjust AC cooling and heating target temperatures from the cloud dashboard without an on-site visit.
- Compare ambient air temperature against water temperatures to diagnose defrost cycles or capacity issues.
Installation
Connect the Modbus RTU wiring (A, B and GND) from the Chiltrix CX34, CX35 or CX50 terminal block to the RS-485 port on your ModbusCloud Gateway.
Verify that the Chiltrix unit is configured for Modbus RTU communication at 9600 baud, 8 data bits, 1 stop bit, no parity, and note the slave address set on the unit.
Set the matching baud rate and slave address in the ModbusCloud gateway configuration so it matches the Chiltrix settings exactly.
Import the Chiltrix CX34 CX35 CX50 template from the ModbusCloud template library and assign it to the gateway port connected to the heat pump.
Power cycle the gateway and confirm that live readings such as outlet water temperature and compressor frequency appear on the ModbusCloud dashboard.
Things to watch for
Why do the temperature values look unusually high on the dashboard?
All Chiltrix temperature registers report values in degrees Fahrenheit. If your dashboard expects Celsius, apply a conversion or check the template scaling settings. A reading of 113 F corresponds to 45 C.
Can I read status and write setpoints on the same register?
Yes. Registers 140 through 146 are dual-purpose. They return current status when read and accept new setpoints when written. The template handles both operations on these addresses.
What baud rate and serial settings should I use?
Configure 9600 baud, 8 data bits, 1 stop bit and no parity on both the Chiltrix unit and the ModbusCloud gateway. Mismatched settings will cause communication timeouts.
Does this template work with other Chiltrix models beyond the CX34, CX35 and CX50?
The template is validated for the CX34, CX35 and CX50. Other models with the same Modbus register map may work, but you should verify compatibility against the Chiltrix Modbus documentation before deploying.
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