DIY Non-thermostatic radiator valve

Living in an old building with radiators that are connected with your neighbors above and below introduces (major) issues if you want to install a thermostatic radiator valve - ie. the pipes will need to be frozen - very costly, plus it is not an ideal season to do this (winter).

I wanted to come up with a cheap solution so that the knob could be turned open/closed via wifi.
Solution: use a valve actuator, normally used for gas/water/gardenhose. These have high torque motors which will work for my radiator.

This is a wifi controlled valve, running on Tuya, that is great, as these can be flashed with tasmota, which ofcourse, I did :slight_smile:

Installing introduced other problems, as the mounting clamp was just too short, I had to create a mounting bracket in tinkercad to create a rigid "frame" where the clamp could be inserted into.


Then I had to remove the existing knob and created a lever to replace it.


Printed them both on my 3d printer (after many iterations :clown_face:)

The end result is a frankenstein-like apparatus, but it is out of sight and (most importantly) it works :

Here, ofcourse, node-red comes into action!

With the valve now running on tasmota, I created mqtt-based flow and with the help of homebridge-mqtt, added it to homekit, added it to my daily heating flow (my other radiators have z-wave driven thermostatic valves, this was the last one to "automate")

The valve opens 90 degrees, which is enough to heat the radiator. Next step will be to have some esp based temperature reading and open/close the valve when needed :slight_smile:


Great stuff. I saw you had put a little Ocotoprint flow on the site, have you taken that any further? I was contemplating making a dashboard with just the essential stuff you need for monitoring a 3D printer for use on the phone.

For octoprint I was actually thinking about using a homekit lightswitch with brightness to show how far the print is :') haha but I am not confident enough to leave the printer by itself at this stage.

The octoprint subflow produces this output for the jobs:

and this for the current printjob:

Should be easy to plug it into the dashboard.
The subflow does need some work for error handling when the printer is offline.

I must have a play with that. Only recently have got the printer. It's great fun. It is an Ender 3 Pro, which seems to be the popular one amongst hobbyists. I was amazed how much the cost has come down over the last few years.

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One of the things I've done installed OctoPi and have that connected to the printer. It is got the mqtt plugin installed. Then both the printer and pi are connected to a power strip that is connected to a smart plug. Else where in my network another flow that watches for mqtt messages and if it gets an end print message, it fires off a half hour timer. If any other message comes in, the time is shut off. After the half hour, that NR sends a shutdown to the pi running OctoPi, waits a minute and shuts off the smart plug shutting everything down.

That's clever, I didn't know there was an mqtt plugin. That looks very useful.
I am not using a pi yet, but the plan is to have a headless server and I was wondering about the best way to handle power down, so thanks for that idea.

Make sure that the plug is rated for higher loads (amps). I am using a sonoff th16 running tasmota, controlled via node-red and homekit. My printer is not playing nicely with octoprint/mqtt plugin (some serial issue), next i am using a raspberry camera, which also lives in homekit. Added some led strips (Pimoroni Mote sticks) which are also controlled via node-red and homekit. :slight_smile:

Hmmm been using a tp-link HS100 for well over a year. Think that might be an issue?

Those are 15amps, should be more than good. My mind is twisted with the (5v) adapter i have to use for my printer.

What power are your printers? I assume the max power will be taken by the heaters. My Ender 3 doesn't seem to have a power label on it.
[Edit] Having searched a bit it seems a hobby printer probably consumes less than 100W on average while printing. Even if the peak is five times that you don't get anywhere near the capabilities of a Sonoff Basic for example.


Even if the peak is five times that you don't get anywhere near the capabilities of a Sonoff Basic for example.

You are correct, I was confused with the xbox-like 5V 10 amp adapter I am using for my printer (small machine). I have a new printer coming which has an AC heated bed, I'm pretty sure I don't want 8 hour long prints with the bed on all that time (up to 600w for the bed only, still not anywhere near 16 amps), I wasn't sure how those plugs are rated.

Even if the bed takes 600W while heating up it will not consume anything like that once it is hot. It will only consume whatever is necessary to keep it up to temperature.
Which prompts me to suggest that (blatant plug coming up), once you get the radiator valve fully working, to have a look at node-red-contrib-pid which will let you control the room temperature using a PID algorithm (which is what the printer uses to control its temperatures). You can initially set it up in node red and then, if considered worth it, you can move the pid algorithm into the Sonoff controlling the valve. The same algorithm is available for the Tasmota software. This has the advantage that if you also have the sensor on the Sonoff (using something like a TH10) then the control will continue even if the node-red server or the wifi is down.

Just a reminder that, when talking about current and power, this changes depending on where you are in the world.

Power (watts) = Voltage x current (amps)

So 10 amps in the UK (~230 V) = 2.3 kW

But in the US (typically 120 V) = 1.2 kW

Similarly, a 1 kW load in the UK would draw about 4.3 A but in the US, that would be around 8.3 A.

For the original SONOFF's, personally I would never want to put a continuous load of more than about 1 kW on them in the UK (e.g. I would assume that the 10 A rating is based on the US 120 V). In fact, I doubt I would trust the originals even to be all that safe anywhere near that level and would probably draw the line at about 500 W maximum.

A relay on an AC load doesn't care much about what voltage it is switching. What matters mostly is the current and whether the load is inductive. Something like a fan or a comperssor fridge for example is much nastier than a resistive load like the heaters in the printer. So a Sonoff rated at 10 A should be capable of driving a 1.2KW heater in the US or 2.3KW in the UK. However I am sure you are right in that the relays are likely to be optimistically rated so I agree that in the US the max I would recommend would be 500W or a bit more, but in the UK they should be fine at 1KW.
The TH16 is rated at 16A, or 3680W in the UK and I do have one driving a 2KW fan heater which has been proved reliable over a period of a couple of years now.

Yes, that's the point. A different mains voltage results in a different current for the same power requirement.

I think we've all seen the YouTube videos of burned out SONOFF's :skull:

That's good to know. I have one of those as well but it is only driving a set of LED's outside. Only about 10 W max I think. I only wanted to check the power use for a bit but I've never got round to replacing it with one of my Basic's :grinning:

I haven’t seen them, but itead actually got them CE certified in the EU, because people were complaining about insurance that wouldnt cover uncertified devices.

Ahem, sorry to burst that assumption. CE markings are self-certified and don't have to be checked in the EU. That is why so many Chinese devices carry them.

How to obtain CE marking?

As the product's manufacturer, you bear sole responsibility for declaring conformity with all requirements. You don't need a license to affix the CE marking to your product, however, before doing so, you must:

  • ensure conformity with all relevant EU-wide requirements
  • determine whether you can assess your product by yourself or if you have to involve a notified body
  • put together a technical dossier documenting conformity: find out about technical documentation
  • draft and sign an EU declaration of conformity

Once your product bears the CE marking — if the competent national authority requests — you must provide them with all the information and supporting documentation concerning CE marking.

Do you need an independent assessment?

You need to check if your product has to be tested by a notified body . You can find this information in the relevant legislation applicable to your product: check the rules by product category.

This step is not obligatory for all products .

If you need to involve a notified body , the CE marking must be accompanied by the identification number of the notified body. The CE mark and the identification number can be affixed separately, as long as they appear clearly linked to each other.

You can use the Nando database to search for a notified body that can certify your product.

If your product doesn't need to be verified by an independent body , then it is up to you to check that it complies with the technical requirements. This includes estimating and documenting the possible risks when using your product.

I am sorry to burst yours, but they actually have them, also RoHS. I am very much aware of the chinese “certifications”.

See test reports at the bottom

Yes, and the certification reports are all signed by Chinese employees.

The CE certificate of compliance relates to the RF noise.

The RoHS certificate relates to the use of hazardous substances not to electrical safety.

Both certs are provided by a Chinese company.

Don't get me wrong, ITEAD have come on a long way and seem to do their best when it comes to electrical safety. They are certainly streets ahead of many of their other Chinese rivals. They've also greatly improved their product design and safety. But, they still only cost a few dollars. This needs to be taken into account when assessing safety. Better safe than sorry. I'm more than happy to use their products but I will remain very cautious.

It would be good to get bigclivedotcom to do some YouTube tests on SONOFF's and get his reaction. :slight_smile:

Ok i digged a little into what you are referring to. Various designs were dangerous due to a missing inline fuse and could cause a fire at heavy (or even not so heavy) load. Some designs have changed and also added different models, certain models are certified for specific countries, like Australia and USA, where some products have FCC certifications. You can search the various databases for the registrations.

Always good to be paranoid :wink:

Anyway we are way offtopic of my beautiful valve :confounded: contraption, the lever already failed, back to the drawingboard