Heating failed on Prusa i3 So this weird error started popping up... Everytime I try to heat up the extruder to print something (and do this just via GCode), the measured temperature will rise fine up until 220 deg (when 230 °C is the target), and will then stop there, forcing the firmware to spit the "Heating failed" error. I can't understand where this is coming from, not really. The error started appearing after separating the heater fan (for the heatsink) and the cooling fan (for the prints) so that the heatsink fan is always on, to prevent jamming. I have tried retuning the PID controller, with no luck. The values I get are really close to the ones I had previously. Also, the extruder has always worked even with the fan on (even though it was gradually turned on mid print), so I don't think it can be an insulation issue... The only thing I haven't done yet is change the section of the firmware where the watch temp is declared, but I don't think that will help in any way, as the temperature DOES NOT increase any further. As far as my understanding of Marlin goes, I know that the PID controller kicks in by default when the temperature is about 10°C from the target (right?), so I'm guessing there's something wrong with it... Maybe autotuning didn't work? :S https://reprap.org/forum/read.php?262,699967,699967#msg-699967 Fri, 12 Jun 2026 19:26:59 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?262,699967,739276#msg-739276 Re: Heating failed on Prusa i3 https://reprap.org/forum/read.php?262,699967,739276#msg-739276 MCcarman Printing Mon, 16 Jan 2017 07:31:32 -0500 https://reprap.org/forum/read.php?262,699967,738719#msg-738719 Re: Heating failed on Prusa i3 https://reprap.org/forum/read.php?262,699967,738719#msg-738719 JamesK Printing Sat, 14 Jan 2017 10:50:55 -0500 https://reprap.org/forum/read.php?262,699967,738717#msg-738717 Re: Heating failed on Prusa i3 https://reprap.org/forum/read.php?262,699967,738717#msg-738717 Krippers Printing Sat, 14 Jan 2017 10:22:30 -0500 https://reprap.org/forum/read.php?262,699967,738514#msg-738514 Re: Heating failed on Prusa i3 https://reprap.org/forum/read.php?262,699967,738514#msg-738514 JamesK Printing Fri, 13 Jan 2017 15:08:18 -0500 https://reprap.org/forum/read.php?262,699967,738511#msg-738511 Re: Heating failed on Prusa i3 https://reprap.org/forum/read.php?262,699967,738511#msg-738511
Once again, a big thank you to those helpful people who took the time to help, and the laugh's on me.

Cheers all

Dizzybear]]> Dizybear Printing Fri, 13 Jan 2017 14:52:03 -0500 https://reprap.org/forum/read.php?262,699967,737657#msg-737657 Re: Heating failed on Prusa i3 https://reprap.org/forum/read.php?262,699967,737657#msg-737657 MCcarman Printing Wed, 11 Jan 2017 08:14:14 -0500 https://reprap.org/forum/read.php?262,699967,737577#msg-737577 Re: Heating failed on Prusa i3 https://reprap.org/forum/read.php?262,699967,737577#msg-737577 Thanks for the info, I haven't checked the bed voltage setting - where will I find it? I'm at work ATM so won't be able to check for a few hours. I'm hoping to spend some time this afternoon fine tuning a hammer to hit it with(:P)

Cheers
Dizzybear]]> Dizybear Printing Wed, 11 Jan 2017 03:16:58 -0500 https://reprap.org/forum/read.php?262,699967,737327#msg-737327 Re: Heating failed on Prusa i3 https://reprap.org/forum/read.php?262,699967,737327#msg-737327 Chances are the driver is limiting the current but the hot end can be doing the same.
Aschie - whats the latest on your issue? Yours seems to be a software issue - The error message "thermal runaway" is being triggered when the temperature is dropping. We need someone familiar with the software to jump in here. I am assuming this is the thermall runaway protection feature.
Seems like your hot end is only just capable of getting to target temp. When you put the cooling fan on its dropping the temperature and the hot end can't recover to target. The software logic compares the fact that the hot end is on max with the reported temperature and recognises its not increasing so flags the error on the assumption that the thermistor is not attached.
I have seen issues with the temperature tables being incorrect so it is worth having a look to see if the values are out of sequence. Also double check you have the correct table/resistor selected.]]> MCcarman Printing Tue, 10 Jan 2017 08:15:17 -0500 https://reprap.org/forum/read.php?262,699967,737218#msg-737218 Re: Heating failed on Prusa i3 https://reprap.org/forum/read.php?262,699967,737218#msg-737218 I measured the voltage across the black & yellow pins as the bed was heating, so yes, it was under load. I have noticed prior to me changing a few bits that I could have the head heating without a problem, but if I heated the bed in isolation it would return the Failed heating message,]]> Dizybear Printing Tue, 10 Jan 2017 02:38:53 -0500 https://reprap.org/forum/read.php?262,699967,737161#msg-737161 Re: Heating failed on Prusa i3 https://reprap.org/forum/read.php?262,699967,737161#msg-737161
Quote
Dizybear
Just a thought, would beefing up the wiring help? If I've got my maths right 24V 15A is the same as 12V 30A.

If the wires from the power supply thru to the bed are not man enough for the amps , then yes you will get a voltage drop across them]]> obewan Printing Mon, 09 Jan 2017 18:16:15 -0500 https://reprap.org/forum/read.php?262,699967,737156#msg-737156 Re: Heating failed on Prusa i3 https://reprap.org/forum/read.php?262,699967,737156#msg-737156
your PSU is 360W which ought to be enough compared with say the 240W ones provided with the Anet A8.

It's not clear whether the 23.5V you are getting is under load or not. It wouldn't hurt to adjust the PSU up to 24V. However if the heating problem only appears when the printer is printing and moving then it could be that you have a poor contact somewhere that is flexing and clearing as the printer moves. Start by re-checking all your 24V power connections from the PSU to the board and from the board to the bed and extruder. If there are screw connections in the run then terminate the cables with the correct size crimp-on connectors and tighten all connections. Some beds have two sets of connections 12V and 24V, make sure that you have connected the 24V ones.

If you can't get any improvement, and the PSU voltage is still varying under load, it could simply be a poor power supply.]]> Supermec Printing Mon, 09 Jan 2017 18:03:49 -0500 https://reprap.org/forum/read.php?262,699967,737086#msg-737086 Re: Heating failed on Prusa i3 https://reprap.org/forum/read.php?262,699967,737086#msg-737086 JamesK Printing Mon, 09 Jan 2017 14:49:50 -0500 https://reprap.org/forum/read.php?262,699967,737079#msg-737079 Re: Heating failed on Prusa i3 https://reprap.org/forum/read.php?262,699967,737079#msg-737079 Dizybear Printing Mon, 09 Jan 2017 14:36:24 -0500 https://reprap.org/forum/read.php?262,699967,737076#msg-737076 Re: Heating failed on Prusa i3 https://reprap.org/forum/read.php?262,699967,737076#msg-737076
The only thing left for me to cahnge after the wires and PSU is the main board:(]]> Dizybear Printing Mon, 09 Jan 2017 14:25:03 -0500 https://reprap.org/forum/read.php?262,699967,737072#msg-737072 Re: Heating failed on Prusa i3 https://reprap.org/forum/read.php?262,699967,737072#msg-737072 Dizybear Printing Mon, 09 Jan 2017 14:12:57 -0500 https://reprap.org/forum/read.php?262,699967,737070#msg-737070 Re: Heating failed on Prusa i3 https://reprap.org/forum/read.php?262,699967,737070#msg-737070 I too have a Hictop Prusa i3 with a heating failed problem. Only with me it seems to be the bed causing the problem. I got this at Christmas, and everywhere people are talking about 12v power supplies. Mine shipped with a 24v 15A PSU, but when I check the voltage at the bed terminals I'm only getting 23.5v - is this right? The heating failure occurs randomly at the beginning of a print, normally one or two layers in. I do have a 20A PSU, but I'm loathe to use it in case I blow the board. I have already replaced the Heater cartridge in the extruder, the thermistor in the block and even a new bed, but I still get the same problem. I need help as it took me a while to convince my wife that it was a neat bit of kit.
Cheers]]> Dizybear Printing Mon, 09 Jan 2017 14:09:53 -0500 https://reprap.org/forum/read.php?262,699967,715737#msg-715737 Re: Heating failed on Prusa i3 https://reprap.org/forum/read.php?262,699967,715737#msg-715737 Rlewisrlou666 Printing Thu, 20 Oct 2016 15:08:51 -0400 https://reprap.org/forum/read.php?262,699967,715712#msg-715712 Re: Heating failed on Prusa i3 https://reprap.org/forum/read.php?262,699967,715712#msg-715712 JamesK Printing Thu, 20 Oct 2016 13:22:27 -0400 https://reprap.org/forum/read.php?262,699967,715705#msg-715705 Re: Heating failed on Prusa i3 https://reprap.org/forum/read.php?262,699967,715705#msg-715705 I'll give it a try then... I've been thinking myself that nothing can really be done...]]> Aschie4589 Printing Thu, 20 Oct 2016 13:06:57 -0400 https://reprap.org/forum/read.php?262,699967,715644#msg-715644 Re: Heating failed on Prusa i3 https://reprap.org/forum/read.php?262,699967,715644#msg-715644
If it's climbing to temp and then failing after a certain time it might just be expanding with the heat to a point that it fails.]]> Rlewisrlou666 Printing Thu, 20 Oct 2016 10:57:37 -0400 https://reprap.org/forum/read.php?262,699967,715636#msg-715636 Re: Heating failed on Prusa i3 https://reprap.org/forum/read.php?262,699967,715636#msg-715636
All right... here's the thing. I seem to have tried almost everything. I printed with and without cooling fans, with PID controlled heating and with bang bang controlled heating, I tried tuning the PID, changing the thermal runaway parameters (up to 10 degrees and 70 seconds). I have tried different models, with different kinds of shapes. I have tried cooling the controller, and that helped a bit. I shielded the hotend from strange airflows coming from the improvised RAMPS cooling solution. I have tried all I can think of. And I still manage to fail prints. This is getting very frustrating.

I know for a fact that the heater works (and by the way, I tried both tightening and replacing the set screws on my bowden extruder), since it successfully heats up. I know that the mechanics work and that the controller doesn't overheat. I know that the thermistors read correct values, and that they are reliable enough for me.

Every single print I've tried in the last days has failed. At right about 45-50 minutes. It almost seems like the error is timed. And yet it's not an SD card error (even if that would be quite weird) nor a fail in the model that is too difficult to print. I'm at loss. I looked around online and the only thing I could find was something about the fan wires possibly causing interference when too close to the hotend. But from the one graph I was able to get through Repetier, the temperature didn't float. It didn't change. It just slowly started to go down and in a couple minutes' time it triggered the error. Just like that, without any other esitation.

Any other insight would be much appreciated! :( :S]]> Aschie4589 Printing Thu, 20 Oct 2016 10:34:55 -0400 https://reprap.org/forum/read.php?262,699967,714211#msg-714211 Re: Heating failed on Prusa i3 https://reprap.org/forum/read.php?262,699967,714211#msg-714211
Quote
davmart12
If any of you should find that the problem is with the temp sensor, DON"T overtighten the set screw! Tighten it to just touching. Don't tighten any further!

What hotend uses a setscrew on the thermistor? A set screw on a glass package would be insanity.]]> JamesK Printing Sat, 15 Oct 2016 20:19:47 -0400 https://reprap.org/forum/read.php?262,699967,714206#msg-714206 Re: Heating failed on Prusa i3 https://reprap.org/forum/read.php?262,699967,714206#msg-714206 If any of you should find that the problem is with the temp sensor, DON"T overtighten the set screw! Tighten it to just touching. Don't tighten any further!]]> davmart12 Printing Sat, 15 Oct 2016 19:37:52 -0400 https://reprap.org/forum/read.php?262,699967,713679#msg-713679 Re: Heating failed on Prusa i3 https://reprap.org/forum/read.php?262,699967,713679#msg-713679 Aschie4589 Printing Thu, 13 Oct 2016 14:02:15 -0400 https://reprap.org/forum/read.php?262,699967,713391#msg-713391 Re: Heating failed on Prusa i3 https://reprap.org/forum/read.php?262,699967,713391#msg-713391 MCcarman Printing Wed, 12 Oct 2016 07:30:55 -0400 https://reprap.org/forum/read.php?262,699967,713331#msg-713331 Re: Heating failed on Prusa i3 https://reprap.org/forum/read.php?262,699967,713331#msg-713331 davmart12 Printing Tue, 11 Oct 2016 23:04:05 -0400 https://reprap.org/forum/read.php?262,699967,713302#msg-713302 Re: Heating failed on Prusa i3 https://reprap.org/forum/read.php?262,699967,713302#msg-713302
The printer has now been working for some time (read: no more than 5-10 prints), and I had managed to solve the heating problem by just switching to bang-bang mode. Everything seemed fine (although temperature fluctuated quite a bit), but the last 3/4 prints all have had the same problem, thermal runaway, which made me switch back to PID controlled temperature... So... It seems constant in happening after 10/20% of the print is done, usually 45-90 minutes after starting. I don't have the printer connected to a PC, so i can't provide detailed graphs, but I see that the registered temperature, the one the LCD freezes over, is 222 out of 230 degrees.
I don't understand what it might be. It's too late for it to be connected to the fan turning on (it does that completely after 1.2mm), and it doesn't seem to be related to the physical conditions of the printer. I don't think it can be a heating problem, as the resistance works just fine. I don't know about the thermistor, so I can't exclude that completely, but that sensor has been performing quite well overtime, and the bowden assemby I'm mounting is fairly new.
Any ideas? Might it be related to firmware? Could it be in some way caused by read errors in the SD?

Once again, thanks for your help!]]> Aschie4589 Printing Tue, 11 Oct 2016 17:27:59 -0400 https://reprap.org/forum/read.php?262,699967,700129#msg-700129 Re: Heating failed on Prusa i3 https://reprap.org/forum/read.php?262,699967,700129#msg-700129
Edit: another round of testing. This time I have increased the printing temperature by 10°C. At the very moment the PID kicks in (around 230°C) the temperature stops increasing, and the Heating failed message pops up. Any insights? It seems to me the extruder is well capable of handling those temperatures, so it must be a software issue?]]> Aschie4589 Printing Mon, 15 Aug 2016 07:38:31 -0400 https://reprap.org/forum/read.php?262,699967,700126#msg-700126 Re: Heating failed on Prusa i3 https://reprap.org/forum/read.php?262,699967,700126#msg-700126 Aschie4589 Printing Mon, 15 Aug 2016 07:30:08 -0400 https://reprap.org/forum/read.php?262,699967,700014#msg-700014 Re: Heating failed on Prusa i3 https://reprap.org/forum/read.php?262,699967,700014#msg-700014 stephenrc Printing Sun, 14 Aug 2016 14:07:55 -0400