HOTEND temperature rises very fast! I mean really fast! 10 deg/sec . HELP!

Nagar1994 2020-03-08 02:07:25 UTC #1

My FOLGER TECH FT5 R2 printer has hotend that rises above a specific hotend temperature and doesnt even stop. It goes 5, 10 degree/sec and goes well above 265 even If target temperature is 200. My printer had THERMAL RUNAWAY ISSUES before and after replacing a bad thermistor with a new one, seems like I am not able to control the temperature.
I have read that controlling the BANG MAX temp helps, but how and where do I find this? Please tell me a short detailed steps and the software needed to import a Code to the firmware since I have no knowledge about the circuitry and zero coding experience. I am currently using SIMPLIFY3D for slicer. If you need more details let me know. Any kind of help is really appreciated.

carefudundae 2020-03-08 04:50:19 UTC #2

Are you using stock firmware?
A pid tune might help, but only if something was changed drastically from stock.
Can you explain more what happened that required a thermistor replacement? Are you sure you replaced it with the right thermistor? I think these use 100k thermistors, but if you put the wrong one in it could read the wrong temp and make the current pid tune waaayyyy off.

Nagar1994 2020-03-10 00:10:09 UTC #3

Well I dont really know what to do. I changed the thermistor because my printer showed ' THERMAL RUNAWAY' error and when I inspected, I found the temperature of hotend going below -10 degree, I replaced the broken thermistor with a new one but the similar product. Can you share me your contact details, your email so we can discuss better?

carefudundae 2020-03-10 04:26:35 UTC #4

Please post any other pertinent details here, I don't want to give out my contact info. You can certainly dm me in this forum, but I'd suggest keeping the conversation public such that others can chime in to help and hopefully the eventual resolution will be of benefit to someone else down the road.

csorrows 2020-04-29 17:39:57 UTC #5

Sounds like a 12v heater running on a 24v supply. Try changing the hotend heater cartridge with a known 24v one. That cartridge has way to low of resistance if it's heating that quickly.

Starman37121 2020-05-15 15:38:20 UTC #6

12 volt heater on 24 volts. YIKES! SNAP, CRACKLE, POP!
I had a lot of trouble with heaters and thermocouples when I first started. I did have some trouble with the wire for the T-Couple breaking. I ended up putting the T-Couple wire along side of the heater wire, inside of heat-shrink tube, making sure I didn't get too close to the heater. Maybe, 2" or 50mm.
Another little thing I did, was to put some Heat-Sink Grease around the heater, T-Couple and nozzle.
That made a big difference for Me. Just a small smear is of Heat-Sink Grease goes a long ways.

It has helped me a lot when I have a problem and I see someone else having the situation. Then there's the answer, within the next few posts.