Bambu Lab HMS_0700_0300 — Chamber Temperature High

What Does This Error Mean?

HMS_0700_0300 means the chamber temperature inside the X1 or P1S has gone above the safe limit — usually around 60°C.
The printer pauses the active print to prevent thermal damage to the lidar sensor and other components.
Open the printer's door, let it cool to room temperature, and resume the print.
This typically happens during long ABS or ASA prints in warm rooms.

Affected Models

Bambu Lab X1 Carbon
Bambu Lab X1
Bambu Lab P1S

Common Causes

Long high-temperature print (ABS, ASA) in a warm room
Auxiliary fan disabled or failed
Door kept closed too long during a hot print
Ambient room temperature too high (above 30°C)
Chamber thermistor reading wrong (rare — would persist after cooling)

How to Fix It

Open the printer's door.

On the X1 Carbon and P1S, open the front door fully.
This vents the chamber and brings the temperature down within a few minutes.
Don't open during a print without pausing first — sudden cool air on a hot bed can cause prints to lift.
Wait for the chamber to cool.

Watch the chamber temperature on the touchscreen.
It should drop below 50°C within 5–10 minutes with the door open.
The print can be resumed once temperature is back in range.
Check the auxiliary chamber fan.

On the X1 Carbon, the chamber has an auxiliary fan that vents heat during high-temperature prints.
Make sure it's enabled in the print settings — Bambu Studio has a checkbox for it.
If the fan is enabled but isn't running, it may have failed and needs replacement.
Lower the room temperature if you can.

Bambu Lab printers are rated for ambient temperatures up to about 30°C.
In summer or warm workshops, the chamber can exceed safe limits during long high-temperature prints.
Air conditioning, an open window, or a fan blowing across the printer all help.
Use a different material if the room is hot.

ABS and ASA prints generate the most chamber heat because they need bed temperatures of 100°C+.
If your room is warm, switch to PLA or PETG for projects until the weather cools.
HMS_0700_0300 is much rarer with lower-temperature materials.

Frequently Asked Questions

What chamber temperature does Bambu Lab consider unsafe?

Around 60°C is the soft limit where HMS_0700_0300 triggers.
The lidar sensor and the cabinet electronics are rated for sustained operation up to that temperature.
Past it, sustained operation risks lidar drift and component longevity issues.

Should I leave the door open for ABS prints?

No — ABS needs a warm chamber for layer adhesion.
The fix isn't to open the door permanently but to keep the room cool enough that the chamber doesn't exceed 60°C with the door closed.
If your room can't manage that, ABS may not be a good choice for your environment.