Hot end reach about 134 then return heating failed error.

As Makertech said, check your connections to the mainboard, as well as making sure the heater block and thermistor are fully seated and not shifting around - if they are even a bit loose the tension forces from the printer moving around can lead to inaccurate temperature readings, and failures. If you are still getting heating failed and/or thermal runaway, try and watch via the screen, or on pronterface or another USB driven software to watch your temperatures.

Default settings are looking for a 6 degree increase in temperature on the hotend over 60 seconds before it triggers a thermal runaway error. Try putting the silicone sock on, and doing what you can to adjust for airflow and draughts. If your hotend temp is very swingy it might not get to temp properly.

configuration_adv.h

#if ENABLED(THERMAL_PROTECTION_HOTENDS)
  #define THERMAL_PROTECTION_PERIOD 60        // Seconds
  #define THERMAL_PROTECTION_HYSTERESIS 6     // Degrees Celsius
configuration_adv.h
#if ENABLED(THERMAL_PROTECTION_HOTENDS)
  #define THERMAL_PROTECTION_PERIOD 60        // Seconds
  #define THERMAL_PROTECTION_HYSTERESIS 6     // Degrees Celsius

The first entry here is how long the temp watching window is in seconds. The second value is how many degrees the hotend should change in that window before triggering the heating failed error. Turning this off completely is a bad idea because it's there to prevent the printer from causing fires/etc if some of the hotend components fail. I upped the period to 120 seconds and dropped the hysteresis down to 4 degrees until I built an enclosure, but that increases the risk of it not catching legitimate failures.

In your case @Renan Motti as you are printing in the 240C range for PETG you might need to adjust these depending on how quickly your hotend can actually reach the higher temps.

You could also try some PID tuning to better calibrate the heating element so it uses less bangbang mode. From pronterface, or your console of choice, with a cold hotend, run

M303 E0 S200 C8

M303 is autotune, E0 is extruder 1, S200 is your target temp, set this to wherver you plan to do the majority of your printing from. C8 is the number of cycles to run. If it runs without issues in after some time you'll get a result that looks like this, taken from http://www.soliwiki.com/PID_tuning

bias: 92 d: 92 min: 196.56 max: 203.75
Ku: 32.59 Tu: 54.92
Clasic PID
Kp: 19.56
Ki: 0.71
Kd: 134.26
PID Autotune finished ! Place the Kp, Ki and Kd constants in the configuration.h

Drop these values into the configuration.h PID Tuning section by either replacing the defaults for the Proforge, or commenting them out and adding your own #define lines as exampled below.

    // Proforge 2/2S
  //#define DEFAULT_Kp 18.48
  //#define DEFAULT_Ki 1.13
  //#define DEFAULT_Kd 75.3
  //Custom Tuned Values
  #define DEFAULT_Kp 19.56
  #define DEFAULT_Ki 0.71
  #define DEFAULT_Kd 134.26

Beyond that, additional t/s will probably be best served if you can provide the temp graph from pronterface/octoprint for the period leading up to the error.

i am getting heating failure and now this thermal runaway, hellpp

using petg

Check your Hotend assembly, make sure that there is a gap between the heater block and heatsink. Also check that the hotend cables are properly secured to the control board.

Made folloing changes to the software:-

configuration.h #define THERMAL_PROTECTION_HOTENDS #define THERMAL_PROTECTION_BED which call a couple configuration details in configuration_adv.h #define WATCH_TEMP_PERIOD 20 // Seconds #define WATCH_TEMP_INCREASE 2 // Degrees Celsius #define WATCH_BED_TEMP_PERIOD 60 // Seconds #define WATCH_BED_TEMP_INCREASE 2 // Degrees Celsius

Still getting heating failed at approx 160 deg (temp set to 200). For both hotend

Any suggestions?

Getting same error on the 2nd hotend. Is ti software problem?