Heatpump Modbus Register 172: Total DHW energy produced for master unit

Technical Definition

The register Total DHW energy produced for master unit at address 172 is used to monitor total dhw energy produced for master unit on the heatpump.

• Protocol: Modbus RTU
• Data Type: U DWORD
• Unit: kWh
• Access: Read Only

How to Read (Python pymodbus)

Use this code snippet to read this specific value via RS485:

from pymodbus.client.sync import ModbusSerialClient

client = ModbusSerialClient(method='rtu', port='/dev/ttyUSB0', baudrate=9600)
client.connect()

# Read Total DHW energy produced for master unit (Address: 172)
# Note: Check if your device uses 0-based or 1-based addressing
result = client.read_input_registers(address=172, count=2, unit=1)

if not result.isError():
    print(f"Raw Value: {result.registers}")
else:
    print("Error reading register")

client.close()

Integration (Home Assistant)

Paste this into your configuration.yaml:

- platform: modbus_controller
  name: "Total DHW energy produced for master unit"
  address: 172
  value_type: U_DWORD
  unit_of_measurement: "kWh"

Connection Diagram

Here is the standard RS485 wiring for this configuration:

graph TD
    PLC[Host Controller / Home Assistant]
    Device[heatpump]

    PLC -- "A+ (D+)" --> Device
    PLC -- "B- (D-)" --> Device
    PLC -- GND --> Device

💡 Engineer's Insight

Analysis: Total domestic hot water (DHW) energy (kWh) produced by the master unit. Measures heat generated for hot water.

Troubleshooting: Zero value may indicate no DHW demand, inactive heating cycle, or a fault in the energy production measurement.