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Why did I make it?

I didn't like the commercially available zone valve controllers because of their high cost and closed source design which would have prevented me from easily integrating into my HomeAssistant server. So I decided to design and build my own zone valve controller to individually control the different zones available in my floor heating system.

What are the features?

An ESP32 is the processor for this board which means you not only get lots of processing power but also a Wifi/BT interface. There are 10x mains powered triac controlled outputs, each triac being rated for up to 1A RMS current. The board is powered via on-board isolated AC-DC converter. Each output channel has an LED attached to signal it's status.

The board exposes a 1Wire as well as an I2C interface via pin headers for connecting to external sensors. Initial programming is done via a VoltLink 6 pin JST-SH header but after Tasmota is flashed, the firmware can be easily upgraded OTA(Over The Air).

There are two fuses used to protect the circuit: F1 is rated for 0.25A 250V (20x5mm glass/ceramic slow blow fuse) and is used to protect the input to the ac-dc converter module while F2 is rated for 1A 250V and is used to collectively protect the triac outputs.

Because of the ESP32 processor this board is Tasmota and ESPHome compatible. By default the board will come pre-flashed with Tasmota. To get started you will need to connect to the access point called "Tasmota_xxxx".

Optionally, when placing the order, you can choose to have your board equipped with the ESP32-WROOM-32UE module (with U.fl connector for external antenna) and you will also receive a high quality 5dBi external antenna and the matching U.fl/SMA pigtail to increase the communication range of the board.

For a full presentation of the board features I encourage you to watch the youtube video linked below.

How do you write software/code for this board?

You can write code in pretty much any development environment that supports the ESP32 but I use the pre-compilated binary of open-source Tasmota which enables me to easily integrate the controller into my home automation system via MQTT.

How do you load code to the ESP32

The system features the VOLTLINK interface for programming. You will need a JST-SH pigtail to connect to a VoltLink programming board or any other ESP32 upload tool that features IO0 and EN signal auto-reset circuitry. Alternatively you can load code via OTA after flashing the board with firmware that supports OTA.

Safety Warnings

This controller board is a DIY type of system and not a ready to go solution. There is an effort required on your side to configure this and get it working in your particular setup. Because this is a DIY project with no safety ratings or approvals, it’s best if you don’t leave it running unattended as I am not responsible for any consequences it might cause.

This controller board uses mains voltage so you need to know what you are doing, otherwise, there is a high risk of electrical shock and/or fire. This is a serious topic, if you are not sure what you are doing, ask for help from an electrician. Every connection should be double checked before applying mains power.

Operation of this equipment in a residential environment could cause radio interference.

If you plan to use the board on a different mains voltage, like 110V or with a different valve actuator with different specs, fuses will need to be adjusted accordingly and F2 can be increased up to 2A which is the limit of the PCB traces.

The 3V3 power brick which powers the control board is isolated and the triacs also provide optical isolation between the ESP32 and the mains side however if you want to be absolutely sure there is no risk of electrical shock I would recommend keeping the board disconnected from mains power during programming and supplying external 3V3 power via the Voltlink connector. Once Tasmota firmware has been loaded, further firmware uploads ca be done safely OTA.

Wiring diagram

Electrical Specs

• Input voltage: 110V-240V AC.
• Output current: up to 0.9A RMS per triac output and up to 2A total combined.
• Load type: resistive loads only. (capacitive/inductive loads might damage the output triacs).
• Low voltage side over-current protection: 0.25A slow blow.
• Operating temperature range (ambient): 0-70°C relative humidity 10-80%.
• Screw connector applicable wire: 24-14AWG.

What you get with your order

You will get 1 x assembled controller board with 240V rated fuses installed and 1 x JST-SH pigtail for the VoltLink programming port. If you are using the controller board on something other than 240V mains, fuses should be replaced accordingly. User switch will be shipped unassembled to prevent damage during shipping.

Optionally you can also order a compatible DIN rail enclosure together with your controller board by selecting this option when adding to cart. Enclosure color will be white or black depending on available stock.

What else do you need to get you started?

You will need some zone valves to install on the individual floor heating circuits. The ones I use are 240V AC rated and they use some form of wax cartridge actuator which takes about 2 mins for a full open or close action. These valves have a pulse current rating of 300mA but that quickly drops to under 10mA after a few seconds.

Shipping delay & exception notice

Because of the current global situation I will not be able to ship to a list of countries as decided by the postal operators. Long delays for delivery are expected especially when shipping overseas.