Free Modbus template: E.G.O. Smart Heater

Name: E.G.O. Smart Heater
Brand: E.G.O.
SKU: a63b0544-b982-4244-a671-0688434cc218

The E.G.O. Smart Heater is a 3.5 kW screw-in heating element for hot water tanks. It turns PV surplus into heat in 500 W steps by switching three internal relays. This template follows the official E.G.O. register map (protocol release 1.6): tank and sensor temperatures, relay status, power setpoint and grid power inputs, temperature limits, relay timing and counters. Default link: address 247, 19200 baud, 8 data bits, even parity, 1 stop bit. The heater expects a new power value at least every 60 seconds and switches off without it.

Things to watch for

The heater does not answer. What should I check?

First the serial settings: 19200 baud, even parity, 1 stop bit, address 247. Many tools default to no parity. Then swap A and B. A steady red LED means the heater has no communication; at first start it can stay red for several minutes until a master polls it. A flashing red LED is a fault that needs a power cycle.

The heater switches off after about a minute.

The heater needs a new value at least every 60 seconds: Power Setpoint in manual mode, Grid Power in automatic mode (Power Setpoint -1). Without it, it switches off. evcc rewrites the setpoint every 30 seconds. This behaviour is reported by evcc and other integrations; the E.G.O. protocol document does not mention it.

Why does the heater ignore my power setpoint?

The rotary selector must be in the heating range, 40 to 80 °C. The heater also switches in 500 W steps and keeps a minimum on and off time per relay, so the setpoint is met best effort and anything below 500 W means off. While Temperature Setpoint is 0, the rotary selector caps the water temperature.

Where is the actual heating power?

There is no measured power register. Add up the Rated Power of the relays that Relay Status reports as on. With the default 500, 1000 and 2000 W elements that is simply Relay Status times 500 W.

Does it work with evcc?

Yes. evcc has the charger template ego-smartheater (sponsor token required), but it only speaks Modbus TCP. For the RS485 version, run an RTU-to-TCP bridge such as mbusd on the evcc host, for example mbusd -L - -A 127.0.0.1 -p /dev/ttyUSB0 -s 19200 -m 8e1 -P 5020, and point evcc at 127.0.0.1, port 5020, id 247. Modbus TCP has no password, so keep the bridge on 127.0.0.1 and open it to the network only behind a firewall when another host really needs it. An RS485 bus allows only one master, so that host must also go through the bridge.

How do I write a negative Grid Power?

Grid Power is a signed 32-bit value, high word first. Write both registers in one FC 16 request. -500 W is 0xFFFF 0xFE0C; 0xFE0C 0x0000 is a common mistake. Negative means export, so the heater heats.

Registers (34)

34 read / 11 write

Name	Address	Function	Type	Unit	Access
Boiler Temperature Water temperature in the tank, 0 to 100 °C. E.G.O. register ActualTemperaturBoiler.	•••	•••	•••	°C	R
Relay Status Bitfield of the three heating relays: bit 0 = relay 1, bit 1 = relay 2, bit 2 = relay 3. Heating power = sum of the Rated Power of the relays that are on (default elements 500, 1000 and 2000 W, so value x 500 W). E.G.O. register RelaisStatus.	•••	•••	•••		R
Knob Temperature Setpoint Position of the rotary selector on the heater, 0 to 80 °C, default 60. Caps the water temperature while Temperature Setpoint is 0. E.G.O. register UserTemperaturNominalValue.	•••	•••	•••	°C	R
External Sensor 1 Temperature Optional external sensor. Special values: -32768 = no sensor input on this model, -32767 = no sensor connected, -32766 = sensor fault. E.G.O. register ActualTemperaturExternalSensor1.	•••	•••	•••	°C	R
External Sensor 2 Temperature Optional second external sensor. Special values: -32768 = no sensor input on this model, -32767 = no sensor connected, -32766 = sensor fault. E.G.O. register ActualTemperaturExternalSensor2.	•••	•••	•••	°C	R
PCB Temperature Temperature of the control board. Above its limit the heater switches off and restarts 10 K below it. E.G.O. register ActualTemperaturPCB.	•••	•••	•••	°C	R
Power Setpoint -1 = automatic mode, the heater follows Grid Power (default). 0 = off. Above 0 = target power in W, met best effort in 500 W steps within the relay minimum on and off times. Must be rewritten at least every 60 s or the heater switches off (reported by evcc and other integrations, not in the E.G.O. document). E.G.O. register PowerNominalValue.	•••	•••	•••	W	R/W
Grid Power House grid power written by the energy manager when Power Setpoint is -1: negative = export, the heater uses the surplus; positive = import, the heater stops. Signed 32-bit, high word first, write both registers with FC 16 at least every 60 s. E.G.O. register HomeTotalPower.	•••	•••	•••	W	R/W
Temperature Setpoint Target water temperature, 0 to 80 °C. 0 (default) = use the rotary selector. Must not be higher than Knob Temperature Setpoint. E.G.O. register TemperatureNominalValue.	•••	•••	•••	°C	R/W
Minimum Temperature Below this temperature the heater heats even without PV surplus. 0 = off (default), otherwise 40 to 85 °C and at least 10 K below the rotary selector setting. E.G.O. register TemperatureMinValue.	•••	•••	•••	°C	R/W
Maximum Temperature Upper limit for the water temperature, 60 to 80 °C, default 80. Applies even with the rotary selector at maximum. E.G.O. register TemperatureMaxValue.	•••	•••	•••	°C	R/W
Relay 1 Rated Power Rated power of the element on relay 1, 100 to 1500 W, default 500. Not a live measurement. E.G.O. register Relais[1].ActualPower.	•••	•••	•••	W	R
Relay 2 Rated Power Rated power of the element on relay 2, 100 to 1500 W, default 1000. Not a live measurement. E.G.O. register Relais[2].ActualPower.	•••	•••	•••	W	R
Relay 3 Rated Power Rated power of the element on relay 3, 100 to 2500 W, default 2000. Not a live measurement. E.G.O. register Relais[3].ActualPower.	•••	•••	•••	W	R
Relay 1 Min On Time 10 to 60 s, default 10. E.G.O. register Relais[1].MinOnTime.	•••	•••	•••	s	R/W
Relay 1 Min Off Time 110 to 180 s, default 110. E.G.O. register Relais[1].MinOffTime.	•••	•••	•••	s	R/W
Relay 2 Min On Time 10 to 60 s, default 10. E.G.O. register Relais[2].MinOnTime.	•••	•••	•••	s	R/W
Relay 2 Min Off Time 170 to 240 s, default 170. E.G.O. register Relais[2].MinOffTime.	•••	•••	•••	s	R/W
Relay 3 Min On Time 10 to 60 s, default 10. E.G.O. register Relais[3].MinOnTime.	•••	•••	•••	s	R/W
Relay 3 Min Off Time 230 to 300 s, default 230. E.G.O. register Relais[3].MinOffTime.	•••	•••	•••	s	R/W
Total Operating Hours Raw value in seconds, scaled to hours. E.G.O. register TotalOperatingSeconds.	•••	•••	•••	h	R
Error Counter Number of errors logged by the heater. E.G.O. register ErrorCounter.	•••	•••	•••		R
Relay 1 Operating Hours Raw value in seconds, scaled to hours. E.G.O. register Relais[1].OperatingSeconds.	•••	•••	•••	h	R
Relay 2 Operating Hours Raw value in seconds, scaled to hours. E.G.O. register Relais[2].OperatingSeconds.	•••	•••	•••	h	R
Relay 3 Operating Hours Raw value in seconds, scaled to hours. E.G.O. register Relais[3].OperatingSeconds.	•••	•••	•••	h	R
Relay 1 Switching Cycles Switching count of relay 1. E.G.O. lists it as a development counter. E.G.O. register Relais[1].SwitchingCycles.	•••	•••	•••		R
Relay 2 Switching Cycles Switching count of relay 2. E.G.O. lists it as a development counter. E.G.O. register Relais[2].SwitchingCycles.	•••	•••	•••		R
Relay 3 Switching Cycles Switching count of relay 3. E.G.O. lists it as a development counter. E.G.O. register Relais[3].SwitchingCycles.	•••	•••	•••		R
Restart Counter Restarts of the internal controller. E.G.O. lists it as a development counter. E.G.O. register RestartCounter.	•••	•••	•••		R
Manufacturer ID Always 5359 (0x14EF) on E.G.O. devices. Read it first to test the connection. E.G.O. register ManufacturerID.	•••	•••	•••		R
Product ID Middle part of the article number, for example 60335 for 29.60335.001. E.G.O. register ProductID.	•••	•••	•••		R
Product Variant Last part of the article number, for example 1 for 29.60335.001. E.G.O. register ProductVersion.	•••	•••	•••		R
Firmware Version Raw 100 = version 1.00. E.G.O. register FirmwareVersion.	•••	•••	•••		R
Relay Count Number of heating relays, 3. E.G.O. register RelaisCount.	•••	•••	•••		R

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E.G.O. Smart Heater

Overview

Key readings

Available commands

Use cases

Installation

Things to watch for

Registers (34)

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