M109 - Wait for Hotend Temperature

thermal Wait for the hot end to reach its target.

This command optionally sets a new target hot end temperature and waits for the target temperature to be reached before proceeding. If the temperature is set with S then it waits only when heating.


M109 [B<temp>] [F<flag>] [R<temp>] [S<temp>]

Argument Description

With AUTOTEMP, the max auto-temperature.


Autotemp flag. Omit to disable autotemp.


Target temperature (wait for cooling or heating).


Target temperature (wait only when heating). Also AUTOTEMP: The min auto-temperature.


With PRINTJOB_TIMER_AUTOSTART this command will start the print job if heating, and stop the print job timer if the temperature is set at or below half of EXTRUDE_MINTEMP.

This command (and M190) can block new commands from the host. To break out of wait for temperature using M108 from the host, enable EMERGENCY_PARSER.

Use M104 to set the hot end temperature and proceed without waiting.


Set target temperature and wait (if heating)

M109 S180

Set target temperature, wait even if cooling

M109 R120

AUTOTEMP: Set autotemp range, wait for temp

M109 F S180 B190

AUTOTEMP: Disable autotemp, wait for temp