Which port do I use for Modbus RTU on the Thermia Genesis?

Connect to the BM-card port labelled MBe inside the electrical cabinet. Make sure you use the correct A and B terminal polarity for RS-485.

Where do I enable Modbus on the heat pump?

Open the Settings menu on the heat pump display and navigate to the BMS section. Both RTU and TCP options can be enabled there.

Why does the compressor available gears value look incorrect?

Register address 4 uses a divisor of 9. The ModbusCloud template already applies this scaling, so if you see unexpected values, check that you have not added an extra manual divisor.

Can I use both Modbus TCP and RTU at the same time?

This depends on the Thermia firmware and configuration. In most cases only one protocol is active at a time. Consult the Thermia installation manual for your specific model.

Free Modbus template: Thermia

This template reads sensor data and compressor status from Thermia Genesis heat pumps via Modbus TCP or RTU. It supports the Calibra, Calibra Cool, Diplomat, and MEGA models. Key readings include outdoor temperature, brine temperatures, tap water temperatures, supply/return line temperatures, and compressor speed.

Name	Address	Function	Type	Unit	Access
Outdoor temperature	14	FC04	int16	°C	R
Tap water weighted temperature	17	FC04	uint16	°C	R
First priority demand	1	FC04	uint16		R
Tap water top temperature	15	FC04	uint16	°C	R
Tap water lower temperature	16	FC04	uint16	°C	R
Brine in temperature	10	FC04	int16	°C	R
Brine out temperature	11	FC04	int16	°C	R
Comfort wheel temperature	5	FC03	uint16	°C	R
Supply line temperature	9	FC04	uint16	°C	R
Return line temperature	8	FC04	uint16	°C	R
Comfort mode	82	FC04	uint16		R
Compressor speed RPM	5	FC04	uint16	rpm	R
Compressor available gears	4	FC04	uint16	/ 9	R
External additional heater: Current demand_	6	FC04	uint16	%	R
Compressor speed percent	54	FC04	uint16	%	R

Thermia

Overview

Key readings

Use cases

Installation

Things to watch for

Registers (15)

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