My Boiler Control Interface

At this stage in of its development I would like to share a “Boiler Room” photo of my set up to control the Central Heating function of a Bosch Worcester Greenstar CDi Boiler using iHost as the Coordinator with Sonoff TRVZB radiator valve heads.
Starting from the top: the large box houses 2 x Sonoff 4CH Pro wifi switches with their NO and C wired in parallel. Each channel acts as a “Slave” to its assigned Sonoff TRVZB “Master”. This forms a logic OR gate. Also in the box is a single Sonoff Basic wifi switch to provide initiation of a synchronisation scene when the box is powered up.
Moving down: the wall mounted Sonoff Basic wifi switch has been modified to “voltage free” relay contact switched by a scene that monitors the external temperature as measured by a Sonoff TH10 wifi switch. If the temperature drops below the scene set threshold the relay contact closes. This forms a logic AND gate with the 4CH Pro Switches to allow the Boiler to fire.
The “Megaflow” box is purely a connection centre.
The manual switches allow the Central Heating Control (CH OFF / CH ON) to be set as required. CFH OFF and CFH ON is for the Boiler Engineer to simulate a Call for Heat condition without having to switch the Control System to ON.
The Manual Mechanical FrostStat is wired in parallel and forms a logic OR gate with the CH OFF / CH ON switch so that if the switch is in CH OFF position and the ambient temperature drops below the pre-set value (currently set at 7 deg C) it will override and switch the system ON.
In developing this system I have kept to using the standard eWeLink scenes in iHost but so far there is still the need to use eWeLink to configure devices via the cloud so Sonoff has still some way to go to make iHost fully stand alone but also fully integrated with eWeLink. That being said the system as is works very efficiently.


Nice. Some proper engineering rather than some nodered IoT software nonsense :slight_smile:


Thank you.

To meet your demands, a change in the Sonoff/eWeLink approach to iHost is required. Designed as a local server, it is unclear why it does not support Sonoff WiFi devices directly, although it does have wireless connectivity built into the hardware. I have been following the development of the iHost concept for many months. I had this device myself until recently. It doesn’t look like what you postulate will come to reality. eWeLink guys are not listening.
Note that your WiFi devices also work in LAN mode. If you have the eWeLink Smart Home add-on, they are controlled locally. With very few exceptions, which is odd by the way. I ran the tests a few times and LAN mode always worked. I was able to control the devices with internet access disabled from within iHost. With another add-on and with the original firmware, I do the same with Home Assistant.
You can still consider the option with replacing the firmware with alternative solution (e.g. tasmotize option), but this is complicated and requires knowledge and skills.
In my case, the LAN-controll option is completely sufficient.

Thank you for your feedback. As you did I also tested the resilience of the system with the internet disconnected from the router that I use for the system. I found that with the Sonoff Basic WiFi switches the function available was limited to just ON and OFF in LAN mode. The Loop Timer function doesn’t operate- this doesn’t cause too much of a problem for me except for 1 switch that I use for startup sync. It powers up in the ON condition and is switched OFF by the loop timer- it’s that change of state which triggers a scene to start the sync process on the TRVZBs. If Sonoff do not migrate the loop and other facilities to the eWeLink Smart Home iHost I will probably mount the start up sync switch so that it can be easy reached to press the button to change its state for a manual reset in the event of internet failure. We can work around many of these shortcomings if we are aware of them. As we found out about the TRVZBs doing a calibration by opening and closing every Monday at Noon it shows that Sonoff need to improve their consumer documentation for the products.

Sonoff needs improvement in almost every area, but insists this will happen in the future.


Ha Ha-- seriously though I’m sure that they will but in the meantime we have to do the best with what we’ve got now. I’ve been using their products successfully for 10 years now without a single device failure and they are very cost effective even with the annoying lack of features working consistently across all platforms.

Has Sonoff actually been around for 10 years? Are you sure? They themselves say that SONOFF has been on the market for several years. In my view, it is about 5-6 years. The term “several” in Sonoff/eWeLink language probably means the same as “soon we add support for this or that”. In other words, in the FUTURE :slight_smile:

What peace and quiet on the forum today. :slightly_smiling_face:
I wonder what the sonoff and ewelink team will write to us tomorrow when they return to work?

Sorry 8 years- checking my records I purchased my first device (Basic WiFi switch) in 2016.

I’m not so critical of Sonoff either. I’ve had some of the basic switches since 2017 and now have iHost with 19 TRVZBs letting me fine tune the temps in each room. I use Node Red to control two Nests using the google API. It’s been working very well for over 6 months and I have the devices on Alexa now using the Matter Bridge. It was so much cheaper than other options. I’ve had all sorts of issues with Homekit and gave up on it when my Hue Bridge consistently errored when I tried to re-pair it. Given the size of Apple, I can’t believe Homekit is so bad.

I’d like matter hub capability, device firmware update on iHost and backup but I guess I have more patience. I’ve managed software dev team around the world, incl. China so I know the challenges.

In that case, and since the challenges are so overwhelming, perhaps they should sell noodles in sweet and sour sauce? Are they not familiar with noodles? That’s a real bummer!