Gateway S3 (Standard WiFi Edition V3)

92,95 incl.VAT/BTW

The EMS Gateway S3 (Standard Edition V3.0) is the only link you need to add your EMS devices to your home automation system.

If your boiler has a service jack you do not need the DC power supply, only the jack cable.

If your boiler does not have a service jack, or it does but you want to mount the Gateway elsewhere you need to get the version with the DC power supply. Both the service cable and the power supply are sold separately as an option below.

In stock

SKU: gw-S3-1 Categories: ,


This ESP32-S3 based Gateway S3 (Standard WiFi Edition V3) is the next generation of EMS Gateways introduced in September 2023.

An EMS Gateway is the only link you need to add your EMS devices to your home automation system.

Just plug in the device into the service jack on the boiler or heat pump with the optional jack cable and stick it to the side of the boiler. If your boiler does not have a service jack, you can also use the EMS/thermostat wires in parallel to the thermostat. No additional cables are needed and everything is powered from the jack itself or from an external 12V power adapter.

This Gateway connects via WiFi to your home network.

Its all neatly packed in a nice and small enclosure (90x50x24mm) that fits into your hand.

In features it is almost the same as the Gateway S32 V2.0 it replaces, but with a slightly faster processor and much bigger memory. Aside from 16MB Flash memory this model adds a 8MB PSRAM to the on-chip 540kB RAM. This new model is therefore perfect for large EMS systems with f.i. heat pumps and multiple heating circuits.

(A new model with Ethernet/LAN will come in November 2023)


  • Plug-and-play connection to the EMS bus with one cable
  • Connects to the EMS bus via the service jack or the EMS/thermostat wires
  • New circuit board based on the Espressif ESP32-S3 with 16MB flash and 8MB of PSRAM.
  • Robust third generation BBQKees EMS bus circuit compatible with all EMS devices
  • 2.4GHz Wi-Fi connectivity
  • EMS-ESP firmware V3.6 or higher
  • Complete responsive webinterface
  • English, German, French, Swedish, Polish, Norwegian and Dutch language selection (more to come)
  • Firmware upgrade via the webinterface or USB-C
  • Configured for Home Assistant
  • Supports the Home Assistant MQTT Discovery protocol
  • MQTT Discovery also works with Domoticz and OpenHAB without plugin
  • MQTT and Restful API for other interfaces like NodeRED and Loxone
  • Telnet console
  • Optional DS18B20 temperature sensors
  • Supports all EMS heating circuits
  • Support large EMS systems with many EMS devices simultaneously
  • Support for EMS, EMS+, Heatronic 3 etc.

Supported EMS device types (See the full list here):

  • Boilers
  • Heat pumps
  • Thermostats
  • Solar modules
  • Mixer modules

Power options:

  • Service jack (with the optional cable)
  • 9-12V DC (with the optionally supplied power adapter)

If your boiler has a service jack you do not need the DC power supply, only the jack cable. If your boiler does not have a service jack, or it does but you want to mount the Gateway elsewhere you need the DC power supply.

You can add your own 12V DC power supply later on but I only support the power supplies that can be ordered with the product.
Do not use cheap audio cables for the service jack as they have very thin wires inside. Only use one of the optional cables below.

On first boot the Gateway will create an access point on which you can login with a browser and make the appropriate settings for your own network. So for this kit you don’t need any soldering or real programming skills. You do however need to properly configure your home automation system. For Home Assistant, Domoticz and OpenHAB the MQTT discovery is available.

It has an additional connector for directly connecting Dallas 1-wire DS18B20 sensors.

The Gateway can be plugged into the service jack of the boiler, or you can connect it to the EMS bus via the thermostat wires instead. In the latter case you need to use the 12V power supply.

Because the Gateway is an ‘always on’ device it contains high quality components like Panasonic and Murata capacitors for maximum longevity of the device.

Included in the kit:

  • Fully assembled and tested Gateway S3 (Standard edition V3.0)
  • Self adhesive strip
  • JST ZH cable for connecting external DS18B20 sensors (sensors not included).
  • Optional: 3,5mm jack cable for the EMS service jack in 50 and 110cm length
  • Optional: 2-pole Euro plug power supply with 12VDC output and 5.5mm DC barrel jack connector (center pin positive).
  • Optional: wall mount bracket.

For all details about this product look at the extensive EMS Bus Gateway product Wiki.

Please consult the information pages before purchase.

The Gateway comes fully assembled, tested on an actual EMS boiler and loaded with the EMS-ESP firmware.

The current firmware of the Gateway already supports the long list of these EMS devices.

If your device is not listed, it might very well be fully or partially compatible. In case you are missing parameters, you can always open an issue on the firmware repository to get support.

If you have an old Nefit Ecomline, Buderus GB112 boiler or the control panel on your boiler looks like one of THESE, then your boiler is not EMS based but iRT. The EMS Gateway will not work on iRT boilers nor is there any support in the firmware.

Additional information

Weight 0,2 kg
Bus compatibility

EMS, EMS Plus, EMS+, EMS2, Heatronic 3


3,5mm Service jack, EMS bus wire screw terminal, JST connector (for DS18B20 sensors)

Input power options

12V DC adapter, Service jack

DC power supply

12V DC power supply included, No 12V DC power supply

Network options

WiFi (wireless)

Origin country


HS Code



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