Heater cartridge

The G1 extruder has three independent heater cartridges, one per heating zone. Each cartridge is a resistive heating element embedded in the barrel wall that heats its zone to the target temperature under Klipper PID control.

Layout

Zone	Klipper name	Location	Role
Feeding Zone	`extruder` (T0)	Top	Pre-melts pellets entering the screw
Melting Zone	`extruder1` (T1)	Middle	Main melting
Nozzle Zone	`extruder2` (T2)	Bottom	Final conditioning before extrusion

Each cartridge is paired with a thermistor (NTC 100k) for closed-loop temperature control. See Temperature sensor disconnected for sensor-specific issues.

Identifying cartridge failure

Zone not heating despite 100% PWM

Klipper applies full power but temperature does not rise
Or: temperature rises briefly, then drops sharply (cartridge connection intermittent)
Check in G1OS console — if the zone stays flat on the graph despite 100% heater duty: cartridge or wiring fault

Temperature reads -95°C or -99°C

This indicates the thermistor (sensor), not the cartridge, is disconnected or failed
The cartridge may still be functional — fix the sensor first before replacing the cartridge
See Temperature sensor disconnected

Temperature oscillates ±5–10°C

Usually a loose sensor connector causing noisy readings — reseat the white terminal connectors
Not a cartridge fault; run PID tuning if it persists after connector fix

Replacement procedure

Power off the printer and let the extruder cool completely (< 40°C)
In the electronics box, locate the heater cartridge wires for the failed zone
Disconnect the heater cartridge connector
Remove the cartridge from the barrel — it is typically held by a set screw or friction fit in the heater block
Insert the new cartridge and secure
Reconnect the wiring
Power on and verify the zone reaches and holds target temperature
Run PID tuning for the replaced zone