OpenTherm Gateway USB Kit

Availability Unknown OpenTherm Gateway USB Kit
5 reviews

Product Code: OTGW-KIT-USB
€ 52.95 Ex Tax: € 43.76
Not in stock.
Estimated delivery time: Availability Unknown

This item is currently not available for backorder.
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This kit contains all the parts and components required to build your own OpenTherm Gateway with USB interface.

The OpenTherm Gateway is an opensource project to monitor and control your OpenTherm compatible boiler, created by Schelte Bron. More in-depth information can be found on his website and there also is a dedicated forum on

PIC programming

This product comes with a pre-programmed PIC with diagnostic firmware. To use this product as an opentherm gateway you have to load the correct firmware. You can update the firmware yourself using the tools you can find on:

From 13-12-2017, the kit comes with a heavier transformer and DC converter so you can power an ESP8266 module for example using the same powersupply.


  • Forward OpenTherm messages between the thermostat and the boiler
  • Report about the messages on the serial interface
  • Change the thermostat setpoint
  • Set the clock of the thermostat
  • Send the outside temperature to the thermostat
  • Smart power support
  • Support Opentherm and on/off thermostat, or even no thermostat at all
  • Read an outside temperature sensor
  • Control the domestic hot water option of the boiler
  • Obtain additional information from the boiler
  • Firmware updates through the serial interface

What is included?

  • 1x PCB
  • 1x PIC processor 16F88P
  • 1x R-78E5.0-0.5 DC/DC-converter
  • 1x Dual opto-coupler PC927
  • 4x PNP Transistor BC558A
  • 1x NPN Transistor BC548A
  • 1x Electrolytic Capacitor Radial 220uF 63V
  • 1x Electrolytic Capacitor Radial 100uF 16V
  • 4x Diode 1N4004
  • 4x Diode 1N4148
  • 1x Zener Diode 4V7
  • 1x Zener Diode 15V
  • 1x Zener Diode 4V3
  • 1x 1/4 Watt 39 Ohm Resistor
  • 2x 1/4 Watt 100 Ohm Resistor
  • 1x 1/4 Watt 220 Ohm Resistor
  • 2x 1/4 Watt 330 Ohm Resistor
  • 1x 1/4 Watt 1.2K Ohm Resistor
  • 2x 1/4 Watt 4.7K Ohm Resistor
  • 1x 1/4 Watt 15K Ohm Resistor
  • 2x 1/4 Watt 33K Ohm Resistor
  • 1x Transformer EI30 15V 2.0VA
  • 1x Header
  • 3x Screw Clamp
  • 1x Enclosure
  • 4x Enclosure foots
  • 1x Power cable
  • 1x USB-TTL cable (Windows 10 compatible!)


Assembly instructions

The design of this gateway is from Schelte Bron. For extensive information about the gateway, please check his website at If you have any questions about this gateway and how to use it, please check the dedicated forum at

Otgw rules on 11/04/2016
5 reviews
Fantastisch product. Seriële flatcable was helaas wel verkeerd gesoldeerd. Eindelijk zelf controle over de CV. CV wordt nu aangestuurd mbv een Plc ipv de zeer matig presterende honeywell thermostaat. Geeft veel inzicht over gedrag van thermostaat.
Marjan on 02/04/2016
5 reviews
Wat ontzettend leuk! Werkt super! Toegepast met de Linux OpenTherm Monitor om een Bosch CV te regelen. Kan nu via de webinterface op afstand de CV in de gaten houden en instellen. Geeft ook inzicht hoe de keteltemperatuur steeds zo laag mogelijk te houden. Geweldig! Dank aan de maker Schelte Bron.
Mike on 03/02/2016
5 reviews
A good product. Only negative was a poor drilling on one of the resistor holes but other than that easy to assemble. Have to drill your own cable entry holes and I added some euro cable glands. Also need fixing screws for the PCB Downloaded the monitor program and firmware easily enough.
Leo on 21/08/2015
5 reviews
Geleverd binnen 2 dagen terwijl er 7-14 voor staan. Mooi! Set is zo compleet dat er zelfs 4 rubbervoetjes bij zitten. Jammer dat vervolgens 4 schroefjes om de print in de behuizing vast te zetten ontbreken en je zelf openingen moet dremelen voor de kabels.
martonisummit on 20/03/2015
5 reviews
Jammer van de interne trafovoeding. Externe 15 v= voeding? Toch mooi product vind ik. Jammer uitverkocht...

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