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Chamber Mintemp error #31215  

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Scott Clemence
(@scott-clemence)
Active Member
Chamber Mintemp error #31215

Just finished the conversion build and did the firmware update and now the first thing that comes up is this red screen with the "Chamber Mintemp error".  When I look that up it is saying to check the thermistor wiring for damage.  I have traced it fully all the way to the buddy board and everything is fine.  I even removed it from the vent on the fans and just let it hang in case it was being pinched there somehow.  But the cable looks good and it is fully plugged into the board.

It won't get past that error so I am pretty much dead till this gets resolved.  Could it be a bad thermistor or something else?  Is there anyway to bypass this error so that I can at least use the printer?

Posted : 06/07/2025 2:35 pm
Diem
 Diem
(@diem)
Illustrious Member

First let's check the obvious - what temperature is your workshop?

Is the printer situated in front of an AC outlet?

Operating Temperature Range is 18 °C - 38 °C

Cheerio,

Posted : 07/07/2025 4:15 am
Scott Clemence
(@scott-clemence)
Active Member
Topic starter answered:
RE:

My shop runs around 75 °F (~24 °C).  

I did contact support through chat yesterday and they are sending me a new thermistor.   Just wish there was a way to test it so I knew it wasn't the board and is indeed a bad thermistor.  

This post was modified 2 months ago by Scott Clemence
Posted : 07/07/2025 1:23 pm
Jürgen
(@jurgen-7)
Noble Member
RE: Chamber Mintemp error #31215

When you wrote that you "traced" the wiring, do you mean visually or with a multimeter? The thermistor resistance should be around 100 kOhm (at 25°C), and you should be able to unplug it from the board and measure that resistance on the connector. If you measure an open circuit or a short instead, the thermistor or its wiring are broken.

Posted by: @scott-clemence

Just wish there was a way to test it so I knew it wasn't the board and is indeed a bad thermistor.  

 

Posted : 07/07/2025 5:53 pm
Scott Clemence
(@scott-clemence)
Active Member
Topic starter answered:
RE: Chamber Mintemp error #31215

Thanks.  I just did a visual inspection by unplugging it and moving the wires to ensure no kinks or breakage.  Everything moved freely and no kinks were found.

I will pull it out and do the resistance test you mentioned.  Which wire do you use to test that resistance as there are 2 wires that feed to it?

Posted : 07/07/2025 6:26 pm
Jürgen
(@jurgen-7)
Noble Member
RE: Chamber Mintemp error #31215
Posted by: @scott-clemence

Which wire do you use to test that resistance as there are 2 wires that feed to it?

You need to measure the resistance between those two wire ends. That will probe the whole chain: wire to the thermistor, thermistor itself, wire back from the thermistor. This is what the mainboard "sees" as well when measuring the thermistor value. A break at any point will result in invalid readings (open circuit).  

Posted : 07/07/2025 6:36 pm
Scott Clemence
(@scott-clemence)
Active Member
Topic starter answered:
RE: Chamber Mintemp error #31215

When I test it with my Ohm meter, I am getting an open circuit in every way I test it.  

wire1 -----------------------------

                                                       -----End

wire2-----------------------------

wire1 to End = Open

wire2 to End = Open

wire1 to wire2 = Open

 

Posted : 07/07/2025 6:38 pm
Jürgen
(@jurgen-7)
Noble Member
RE: Chamber Mintemp error #31215

I'm not sure the measurements to the "end" are meaningful. You mean the little metal can of the thermistor, right? I don't think that is electrically connected to anything; it's just meant to provide some mechanical protection while conducting heat.

But the open circuit from one wire end (on the connector) to the other wire end does indicate a failure. Either one of the wires is broken somewhere, or the thermistor itself. Which in this case is good news, since there is good reason to assume that the new thermistor will fix the problem.     

Posted : 07/07/2025 6:43 pm
Scott Clemence
(@scott-clemence)
Active Member
Topic starter answered:
RE: Chamber Mintemp error #31215

Thanks for the input.  I feel a lot better now knowing it is a faulty thermistor and not the board.  Not to say something else won't be bad after I put this new one in.  I can't find that out until I get past this error.

Posted : 07/07/2025 6:44 pm
gb160
(@gb160)
Reputable Member
RE: Chamber Mintemp error #31215

Tell support and they’ll send you a new thermistor. The wire on those things is barely a hairs width, Ive already had mine fail in the hot end. If you can get the printer powered up, go to info->sensors …if it’s reading around zero degrees or just over it’s definitely the thermistor at fault….or more likely the wiring to the thermistor.

Posted : 07/07/2025 7:38 pm
Hoang Tran
(@hoang-tran)
Member
RE: Chamber Mintemp error #31215

Hi Scott,

Have you by the way got your chamber thermistor issue sorted out? I have just received the replacement thermistor, but the error still persists.

If you managed to resolve the issue, please could you kindly share the method?

Thanks for your help if you managed to resolve it.Chamber thermistor error Chamber thermistor on the xBuddy Board Chamber thermistor

Posted by: @scott-clemence

Just finished the conversion build and did the firmware update and now the first thing that comes up is this red screen with the "Chamber Mintemp error".  When I look that up it is saying to check the thermistor wiring for damage.  I have traced it fully all the way to the buddy board and everything is fine.  I even removed it from the vent on the fans and just let it hang in case it was being pinched there somehow.  But the cable looks good and it is fully plugged into the board.

It won't get past that error so I am pretty much dead till this gets resolved.  Could it be a bad thermistor or something else?  Is there anyway to bypass this error so that I can at least use the printer?

 

Posted : 16/08/2025 4:19 am
k1mu
 k1mu
(@k1mu)
Trusted Member
RE: Chamber Mintemp error #31215

Your error says "Chamber mintemp error".  But your picture is of the thermistor on the Nextruder. 
The chamber thermistor is mounted to the fans on the back of the enclosure. Are you sure you're checking the right thermistor?

Posted : 16/08/2025 3:07 pm
Scott Clemence
(@scott-clemence)
Active Member
Topic starter answered:
RE: Chamber Mintemp error #31215

 

Posted by: @k1mu

Your error says "Chamber mintemp error".  But your picture is of the thermistor on the Nextruder. 
The chamber thermistor is mounted to the fans on the back of the enclosure. Are you sure you're checking the right thermistor?

It was the thermistor that mounts to the fans in the chamber, I was just holding it next to the nextruder.  Prusa sent me a new one and that fixed the error.  It was a bad thermistor.

 

Posted : 16/08/2025 6:14 pm
2 people liked
Hoang Tran
(@hoang-tran)
Member
RE: Chamber Mintemp error #31215

Hi Scott,

Thanks for the response. You're right. I looked at the wrong thermistor. It's the fan thermistor on the back. I passed the test with the new replacement now. Thank you have a good week ahead.

Posted : 18/08/2025 4:42 am
1 people liked
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