HOT BED 220V DUETWIFI RESET



  • Hello I have a problem, I have a hot silicone bed connected to duetwifi using a relay, the problem is when I turn on the hot bed from the web interface the duet wifi turns off and on, only the wifi connection, and the red leds of the cables of the bed blink once, does anyone know that it can be?



  • Check your wiring. And, please, for your own safety, use protective earth. Mains heaters are more dangerous - if something goes wrong, you could energize the metal parts of your build with mains voltage.

    In your case, I would first check if the problem persists if you unplug the relay and switch the bed on/off in the firmware. If it does... That means that there's an overlap in the 2 circuits somewhere. Power everything down and check with the multimeter if there's a connection somewhere where it shouldn't be. The 2 circuits (low voltage DC and 220 V AC) on your system should have zero cross between one another. It could also be a faulty SSR, so check that as well.

    And I can't really emphasize that enough: ground all of the metal parts if you're using AC heaters. Provided that your house has GFCI and you've plugged everything correctly, that will protect you in case the heater goes haywire and energizes the frame.



  • @mike said in HOT BED 220V DUETWIFI RESET:

    Check your wiring. And, please, for your own safety, use protective earth. Mains heaters are more dangerous - if something goes wrong, you could energize the metal parts of your build with mains voltage.

    In your case, I would first check if the problem persists if you unplug the relay and switch the bed on/off in the firmware. If it does... That means that there's an overlap in the 2 circuits somewhere. Power everything down and check with the multimeter if there's a connection somewhere where it shouldn't be. The 2 circuits (low voltage DC and 220 V AC) on your system should have zero cross between one another. It could also be a faulty SSR, so check that as well.

    And I can't really emphasize that enough: ground all of the metal parts if you're using AC heaters. Provided that your house has GFCI and you've plugged everything correctly, that will protect you in case the heater goes haywire and energizes the frame.

    Thanks I think the relay is defective, when I unplug it from the relay duetwifi it turns on to warm up, so it's a faulty relay.

    Thank you.



  • @ivang What kind of a relay is it? If you went for an SSR, you could have mistakenly chosen a DC/DC one. Although even in that case it'd just die a quick death and not bridge the 2 circuits.





  • @ivang Don't use that! It's a mechanical relay that's only rated for 12V. Running 220V at the output is dangerous and has probably just fried the contacts. I'd advise you to get a DC/AC Solid State Relay. I don't know where you are, but you can easily get those off Amazon and e-bay. Just make sure it's the DC/AC type.



  • @mike said in HOT BED 220V DUETWIFI RESET:

    @ivang Don't use that! It's a mechanical relay that's only rated for 12V. Running 220V at the output is dangerous and has probably just fried the contacts. I'd advise you to get a DC/AC Solid State Relay. I don't know where you are, but you can easily get those off Amazon and e-bay. Just make sure it's the DC/AC type.

    You mean that the connectors on the board broke? I had connected it before but when I saw it did not work, I removed it.



  • I would strongly avoid anything that website sells, they are marketing a 12v relay as able to switch 220v mains.

    "Ideal for silicone beds up to 450W approx. (max up to 40x40cm)

    We also leave the connection of the pins for use with 220V beds:"

    Mechanical relays in general are much more prone to failure in addition to being noisy.

    I strongly suggest you do a lot more research into working with an AC bed before you proceed any further, as mains voltage can be deadly. There are many relevant topics on the duet forums in the past few days that at the bare minimum I suggest you read.



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  • I was referring to the contacts inside the relay - it's a mechanical one, there's a lot more stress on them if they're switching a higher voltage. Wow, I haven't noticed that they actually advertised it as 220V compatible. That's extremely irresponsible and downright dangerous. And I would really advise you to follow the suggestion above, mains voltage is a lot less forgiving.



  • Thanks for the answers, I think I will buy this rele ssr in Amazon, what do you think?

    https://www.amazon.es/gp/product/B0716RTYMD/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1



  • @ivang This one won't do. Look closer - it's a DC/DC relay. You need an DC/AC one, like https://www.amazon.es/heschen-Single-SSR-40DA-estado-sólido/dp/B071HP9NJD/ref=sr_1_5?ie=UTF8


  • administrators

    I concur, use a DC/AC SSR for switching a mains voltage bed heater. See https://duet3d.dozuki.com/Wiki/Choosing_a_bed_heater#Section_Mains_voltage_AC_bed_heater.


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