# How to decrease sensitivity to heat-bed temperature?

Sometimes I use a DIY 3D printer running Marlin firmware and I have a hard time to set my heat bed temperature. when I set it to 70 °C for PLA, after a few minutes it decreases to 67 °C and I see these error:

READ: Error:Thermal Runaway, system stopped! Heater_ID: bed


Since then the communication with printer is lost, the printing process stops and I have to reconnect to serial port... It's a disaster. I guess I need to lower the sensitivity to 3 degrees at least. I don't know how!?

• Have you PID tuned the heated bed?
– 0scar
May 7 '19 at 10:58
• aside note: as an upgrade you can add an insulation under your HB to keep the temperature more constant May 7 '19 at 11:32
• @0scar No, I'm using the default pid parameters. I Thought it would mess it up if I changed them. May 7 '19 at 11:48
• @ darth pixel , I'm using an insulator, however it doesn't cover all the surface beneath HB. May 7 '19 at 11:49
• First thing to do is do a PID tuning session! :)
– 0scar
May 7 '19 at 11:57