La Marzocco Espresso Machine Error Code: Coffee Boiler 1 Probe Failed
Coffee Boiler 1 Probe Failed means the CPU does not detect the coffee boiler temperature probe. The CPU shuts down and turns off the machine. The manual says to reset by verifying and reconnecting the temperature probe, which is a technician job.
High: the CPU shuts the machine down because it cannot read the brew temperature.
- Code
- Coffee Boiler 1 Probe Failed
- Maker
- La Marzocco
- Equipment
- Espresso machines
- Applies to
- Linea PB and Strada AV
What does La Marzocco Coffee Boiler 1 Probe Failed mean?
Brewing temperature depends on the coffee boiler probe. The CPU reads the probe constantly and uses it to hold the boiler at its set temperature. If it no longer detects the probe, for example because the signal is open, the CPU cannot regulate the boiler and shows Coffee Boiler 1 Probe Failed. The manual states that the CPU shuts down and turns off the machine. The action it gives is to reset by verifying and reconnecting the temperature probe. In practice that means checking the probe connection and its wiring, not just pressing a button. The number in the message identifies the boiler on machines with more than one. Because brewing at an unknown temperature gives poor shots and risks overheating, the machine does not carry on without the reading.
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
- Coffee Boiler 1 Probe Failed on the display
- Machine shuts down
- No hot water or espresso available
- Message returns after switching on
Possible causes
Likely causes — what usually sits behind Coffee Boiler 1 Probe Failed on this control. A technician confirms which one it is before any part is replaced.
- Coffee boiler 1 temperature probe disconnected
- Probe lead broken or damaged by heat
- Probe connector loose or corroded
- Probe input on the CPU not reading
Safe checks before calling for service
- Switch the machine off and let it cool.
- Do not open panels or touch the boiler.
- Switch it back on once to see whether the message returns.
- If it does, leave the machine off.
- Note the display text and whether the machine had been moved or serviced recently.
How a technician diagnoses Coffee Boiler 1 Probe Failed
- Read the message and confirm the boiler number.
- Inspect the probe connector and lead for looseness and damage.
- Measure the probe resistance with power off and compare it with the boiler temperature.
- Reconnect the probe and test the CPU input.
- Replace the probe or lead if it fails, then verify brewing temperature.
- The probe is mounted in a hot pressurized boiler.
- Its connector sits in the electrical area at line voltage.
- A meter and reference temperature are needed to test it.
How Coffee Boiler 1 Probe Failed differs from similar codes
This is the coffee boiler probe. Steam Boiler Probe Failed is the same message for the steam boiler.
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 the boiler broken?
Not necessarily. The probe or its connector often is.
Can I reset it?
The manual's reset is to verify and reconnect the probe.
The number is 1. Does it mean one boiler?
It identifies the coffee boiler the message refers to.
Need help with La Marzocco Coffee Boiler 1 Probe Failed?
A technician confirms the cause on site and gives you the price in writing before any work starts.