Dimmer 2 overtemperature error

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  • Hi muttleyluke , welcome to the forum. :)

    L on SW1 is the same L on L?:/

  • Thanks..

    Sorry for mistake...

    O / N / L / SW1 correctly connected.... NO connection on SW2.

    Lights works fine.. but after few seconds/ minutes alarm appears and turn off the light...

    Thanks for help

  • Please check the temperature without load per http-request:

    ip of dimmer/status

    Maybe, the shelly is defect.

  • Same problem here.

    3 halogen lamps TOT 360W

    downgraded to FW 1.7.2

    Temperature in OFF position around 57° C

    ON 52%, about 180W, after about 45 seconds Temperature around 105° C, auto OFF

    Upgraded to FM 1.8.3

    15% 73w, after about 1 minute 105°C, outo OFF

  • I also have this temperature issue with one of my Shelly 2 dimmers. The first week it worked flawlessly and suddenly (after a firmware update v1.8.4) it started with this issue. Temperature rises to 105 degrees Celsius in matter of minutes on a load of 72 watts. Dimming down helps to increase the overheating time. 25% keeps it stable at round 80 degrees Celsius.

    Downgrading the Shelly to v1.8.2 did not provide an improvement, so it seems it is not related to the firmware. The other dimmers I have upgraded have no issue up till now.

    UPDATE: I changed the dimmer from leading edge to trailing edge and did a recalibration and suddenly the temperature started to act correctly again ! As a test I set it back to leading edge and the temperature problem occurred again.

  • Hallo Macelen

    Danke für deinen Beitrag das war die Lösung.

    Habe bestehende Kalibrierung gelöscht auf „Trailing Edge“ umgestellt und neu Kalibriert. Bei Licht1 7 LED Spots a’ 5 Watt und bei Licht2 5 LED Spots a’ 5 Watt brennen seit mehreren Stunden ohne Probleme.

    Danke echt super von dir

    Lg GutMan

  • Hello,

    I'm having same problem with overtemperature.

    Only 10 LED GU10 bulbs (7W aprox each).

    Testing Leading edge and Trailing edge and checking the status.

    I've noticed this:

    * If brightness is 100% , the temperature is Ok (55º cent) as dimming really is not working

    * If bright is 20%, temperature increases but slowly until 75º aprox

    * If bright is 50%, temp increases VERY FAST and gets 105º in a couple of minutes (overtemperature and turn off).

  • I’m experiencing exactly the same issue, with 8 x 7W LED GU10s on firmware 1.8.4. Changing the calibration makes no difference.

    My lights go off as soon as they get to 100% and it’s often too quick to see the temperature increase and go out on thermal cutout; we’re talking 3-5 seconds!

    I can replicate the issue on another Dimmer 2 by setting the levels to 50%.

  • I have bought two Dimmer2 devices. I had the same issue with my first Dimmer2. I have tried everything: calibrating with and without ¨trailing edge¨, N, firmware version etc. I doubted my knowledge about electric wiring and I gave up ... .

    After a month I decided to try the other Dimmer2 device I have bought - just for the sake of it (and I was bored). And what a surprise! It worked with the very fist try without any issues! It is now running for 3 weeks and temperature never went above 55C.

    Long story short: the Dimmer2 device was a DOA device.


    On both my Shelly Dimmer 2s running firmware 1.8.4, with either trailing or leading edge calibration it would cause the temperature to hit 100 Degs C and cut out.

    I downgraded the firmware to 1.8.2 and trialled with leading edge and the temperature still hit 100 Degs C and cut out. I changed it to trailing edge and now it all works, stable at around 65 Degs C with any % load.

  • Hi, I installed my first Shelly, a dimmer2, this afternoon. I connected it to Domoticz through MQTT and saw that the temerature rose quickly to 97,8 degrees celcius at 90%. There are 6 LED bulbs in the lamp, together they are approx 36W or something. The overheating warning did not kick in but I do not feel comfortable with something that hot in my wall. Furtheremore I read that the cut-off temp is 95 degrees celcius, which did not seem to be the case.

    I stumbled upon this thread, changed the calibration to trailing edge, and the temperature immediately dropped to 56,8 degrees at 90%, now it is 54,3 at 90%.

    It seems that leading/trailing edge makes a lot of difference. However, the temp drop is so quick, almost 40 degrees celcius in 1-3 minutes (97,8 -> 56,8) that I wonder if the temperature reading is correct at all. Maybe the 97,8 was a wrong value at all and the Shelly never got this warm?

    Has anyone actually measured the temp, to ascertain if the temp reading is correct?

  • I received the following from Shelly Tech Support:


    Our cannot trigger fire, all parts are certified to run on 120C continuous work, protection is triggered on 95C.

    My ticket is still open...