La Marzocco Espresso Machine Error Code: Steam Boiler Overheated
Steam Boiler Overheated means the steam boiler temperature exceeded the maximum allowed. The manual says to call a service technician, and the CPU also turns power off to the steam boiler.
High: the steam boiler exceeded its maximum, a safety condition.
- Code
- Steam Boiler Overheated
- Maker
- La Marzocco
- Equipment
- Espresso machines
- Applies to
- Linea PB and Strada AV
What does La Marzocco Steam Boiler Overheated mean?
The CPU compares the steam boiler temperature with an upper limit and cuts power to the steam boiler if it is exceeded, showing Steam Boiler Overheated. The manual says to call a service technician. Overheating can come from a heater that stays on, from a probe that reads low, or from a boiler that has too little water. A steam boiler holds water and steam under pressure, so the CPU does not wait for an operator to react. It is the high-limit counterpart of the not heating message for the same boiler. Do not try to restart repeatedly to test it. In daily use the sign is steam that suddenly gets wetter or harsher, a wand that sputters, or a machine that goes quiet when the heater is cut. After the boiler has cooled the display may clear, but the cause is still in the machine until a technician has tested the heater control and the pressure limit devices.
Affected models and control systems
La Marzocco Linea PB (display software, Operating Manual V3.2) and Strada AV (MAN.16.1.01 V1.0). Boiler names and numbers on the display follow the machine's group and boiler count.
Code numbers and their meaning can change between control generations. We match the full model and control before acting on a code.
What you may notice
- Steam Boiler Overheated on the display
- Steam boiler heater cut off
- Steam wand hissing or very hot
- Pressure gauge reading high
Possible causes
Likely causes — what usually sits behind Steam Boiler Overheated on this control. A technician confirms which one it is before any part is replaced.
- Steam boiler heater relay stuck closed
- Steam boiler probe reading lower than actual
- Boiler short of water because of a fill problem
- Pressure control not switching the heater off
Safe checks before calling for service
- Switch the machine off and keep clear of the boiler and steam wand.
- Let it cool completely.
- Do not restart repeatedly.
- Check for leaks or steam, without opening panels.
- Note the display and the pressure gauge reading if visible.
How a technician diagnoses Steam Boiler Overheated
- Read the message.
- With power locked out, check the heater relay for welded contacts.
- Compare probe and pressure readings with a reference.
- Verify water level and the autofill operation.
- Replace the failed part, then confirm control.
- A steam boiler holds scalding water and pressure.
- A welded relay is a line-voltage problem.
- A meter and gauges are needed.
How Steam Boiler Overheated differs from similar codes
This is the over-temperature message for the steam boiler. The coffee boiler has its own.
Technical reference
- Maker documentation
- La Marzocco owner support
- Edition
- V3.2 - 12/2015 (La Marzocco S.r.l.)
- Models / control
- Linea PB and Strada AV
- Section
- Troubleshooting, printed pp. 104-105 (PDF pp. 104-105)
- Checked
- October 2026
We use the maker's document to read the code and do not reproduce it. Always confirm the complete model and control before applying these steps.
Related La Marzocco espresso machine error codes
Is it a pressure risk?
A steam boiler can hold pressure, so keep clear and let it cool.
Can I reset it?
The manual says to call a technician.
Could low water cause it?
Yes, a short boiler overheats faster.
Need help with La Marzocco Steam Boiler Overheated?
A technician confirms the cause on site and gives you the price in writing before any work starts.