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[Guide]Valve teardown guide

Posted: 14 Oct 2018, 12:22
by schmaker
Hello guys.

As i struggled to teardown valve in time because my radiator valve was dripping into smart valve electronics and the valve is dead now, i tried my wasted money to something actually usefull and created this guide for you.

Maybe it saves you couple of bucks when i was out of luck.

So, let's start:

There are 3 pins that holds top cover in place:
Don't be scared, just do some prying and the top cover will jump out easily.

Re: [Guide]Valve teardown guide

Posted: 14 Oct 2018, 12:25
by schmaker
You can now slide the outside shell from the bottom cover of the valve. No big deal happening.
Underneath top cover there is circuit board with controller motor held by two screws. Time to start being carefull as there is flex cable with e-ink display connected.

Re: [Guide]Valve teardown guide

Posted: 14 Oct 2018, 12:31
by schmaker
Time to GENTLY remove the glued e-ink display. You have to be super carefull as the glue sticks quite well and you dont wanna broke the display nor the flex cable powering it.
If needed, you can now remove the e-ink display from PCB. It's just matter of prying the holder on the connector, the flex cable will come of.

Re: [Guide]Valve teardown guide

Posted: 14 Oct 2018, 12:40
by schmaker
This is the design issue that killed my valve.
The valve on my radiator wasnt leaking bad or anything like that. It was just slowly (and by slowly i mean like one drop after few minutes) dripping, but if you mount smart valve with display facing upwards, then the PCB is on the bottom side and water drips directly on the PCB.

No matter how big or small the leak is, it flows directly to the valve electronics effectively killing it.

Fix the design please NETATMO

After i fixed my radiator valves, then smart valve works quite well though and i would recommend it to anybody needing better heating schedules, especially when you have individual boiler, just remember to check if the radiator connections are dry and try also the termostat stick with pliers if it's not leaking.

I took my time writing this guide hoping for saving money for some of you being scared to disassembly wet valve as i was. It's not hard at all to get it all of and dry, but remember to be as fast as possible doing this. Time + water in electronics is killer combination

Re: [Guide]Valve teardown guide

Posted: 17 Oct 2018, 20:31
by steverabs
Thanks very much for that guide. Could be very useful if anyone gets similar issues. It also answers my usual curiosity which is, what's inside and how does it work. Out of interest how rugged is the gear assembly, that's if you stripped it down that far?

Re: [Guide]Valve teardown guide

Posted: 18 Oct 2018, 18:07
by schmaker
I didn't, but will check that out for you.

Edit: I tried to reach the motor, but i was unable to get the push rod off without any damage. I still hope i will somehow fix the valve, so maybe after i fail ill check that out again

Re: [Guide]Valve teardown guide

Posted: 10 Nov 2018, 12:14
by KDpt
Hi,as I posted earlier, I renewed all my downstair Rad Valve
bodies yesterday and never noticed it before:

I had to quickly remove a Valve Head (there is no protection from

NB Be very careful of water damage to valve if the rad air bleed
valve is directly above the Netatmo Valve. All 13 of my Rad Valves
are directly below the bleed valves, because the valve body is taller
than the cap the water is funneled straight to the inner workings.

Looking at making/finding a stand off cap to allow air circulation
but protect the Valves. If anyone has already found a simple answer
please post.
...(or drain the whole system & move the bleed valves).

Re: [Guide]Valve teardown guide

Posted: 10 Jan 2019, 21:37
by mhaga
Good job posting this detailed teardown and also making us able to see what's inside the valve thermostat.

I have had my fair share of problems with the well known problem "valves not closing".
It came to my mind that I could investigate what kind of motor is used in the valve thermostat, as my experience until now show that the problem surfaces more rapidly as the batteries empties. I suspected that the motor used, was not a proper stepper, but it seem like it is. It should be able to perform its calibrated stroke, even if the terminal voltage decreases over time. However the rated voltage for this motor is 3,2V (!) The valve thermostat have only 3.0 Volt from the serial 2xAA batteries and I wonder if this could be the cause of the problem.
I can even see the rated voltage on the pictures taken.

Currently manual recalibration seem to close my valves every time, so I can stopp the heating, but I have to monitor this continuously.

Have anyone found the exact specs of the 25BJY-01 motor? Like holding torque, step angle and so on. It would be interesting to know the accuracy for this stepper motor.
By the way, anyone tested singe SL760 type battery, 3,6 Volt and one dummy battery? They have a little less Ah though. I might break something else, as the terminal voltage of one is 0,6 Volts higher than 2xAA. Maybe it breaks the power supply... Just at thought... Maybe Netatmo could test this for us?

Anyways. Thank you schmaker for your very thorough teardown and information. Good job. Very useful.


Re: [Guide]Valve teardown guide

Posted: 10 Jan 2019, 22:02
by Tommaso Florino

Re: [Guide]Valve teardown guide

Posted: 10 Jan 2019, 22:55
by mhaga

Good one. If this is the one, it should do the job very well. Even at voltage below 3 Volt.
Also this one should be able to regulate my valves with 1% steps easily, even with maximum backlash.
Its all up to Netatmo programers then... It would be good to get this confirmed by Netatmo though. I have requested this engineering information several times, but no answers to this very specific question, unfortunately. :D

It might be something wrong with my math, but I assumed my valve bodies are up to spec. 4mm stroke from fully close to fully open.
This stepper has 5mm stroke. Maximum backlash=0,01664mm(8 steps) Stroke/step 0,00208mm. By my calculation this should be good, but I will try to do it again...

Thank you