HMS 0300-1E00-0001-0003: left nozzle heater over temperature
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HMS 0300-1E00-0001-0003 means the left nozzle went past its temperature limit and the protection stopped it. Something kept the heater on past the point it should have backed off. On a hotend that is nearly always the temperature sensor reporting cooler than reality, and occasionally the control side being stuck on.
Affected machines: H2 series. A hotend has very little thermal mass, so it overshoots quickly when the control loop is working on bad information. That speed is why the firmware treats this as a stop rather than a warning.
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Three things make a nozzle overshoot
A sensor reading low. If the thermistor reports 240 degC when the block is at 280, the controller keeps heating. Measure it cold and compare with the right-hand side: both should read close to the same figure.
A missing or damaged silicone sock. The sock is not only insulation; it also keeps the sensor bedded against the block. A sock that has torn or been left off lets the sensor sit slightly away from the metal, and a sensor measuring air reads lower than the block it is supposed to be reading.
A stuck control circuit. Less common, and the case where the heater receives power regardless of what the controller asks. If both sensors measure correctly and the overshoot repeats, this is what remains.
Left nozzle overshoots its target and the printer reports over temperature
Temperature sensor reading low, a missing or torn silicone sock, or a stuck control circuit
- Power off at the wall and let both hotends cool completely.
- Check the silicone sock on the left hotend. Replace it if it is torn, hardened or missing.
- Confirm the sensor is properly bedded in the block rather than standing proud.
- Measure the left temperature sensor cold and compare with the right-hand one.
- Reseat the toolhead connector, since a poor contact can distort the reading.
- If both sensors match and the overshoot repeats, record the code and raise a support ticket.
Do not clear and continue printing. An overshooting nozzle can cook filament into the melt zone and turn a temperature fault into a jam, which is a longer job than the original problem.
The sensor fault on the same nozzle is left nozzle sensor open circuit, and the opposite symptom is nozzle cannot reach temperature. Our pages on the hotend and clogged nozzles cover what follows.
HMS 0300-1E00-0001-0003 FAQ
Can I print on the right nozzle?
Single-material jobs on the right tool, yes. Do not run anything that switches tools.
Why does the silicone sock matter?
It insulates the block and keeps the sensor seated. Without it the sensor reads cooler than the metal it is measuring.
What should the sensor read?
The same as the healthy right-hand one at the same room temperature. The comparison beats any published figure.
Has the overshoot damaged anything?
Usually not, but check for cooked filament in the melt zone before the next print.
LayerWalker
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