Hamilton Beach Commercial Blender Error 51: Motor Temperature Sensor
Error 51 on a Hamilton Beach Commercial HBH750, HBH755 or HBH850 blender means a bad reading from the NTC, the sensor that measures motor temperature. Unplug the blender, let it rest, and check that the jar sits properly. If 51 returns, call us to test the sensor and board.
Medium: the blender may refuse to run, but the cause is in a sensor circuit and not a safety hazard in itself.
- Code
- Error # 51
- Equipment
- Blenders
- Applies to
- HBH750 / HBH755 / HBH850 display
What does Hamilton Beach Commercial error # 51 mean?
The blender watches motor temperature through an NTC sensor, a small part whose electrical resistance changes with heat. The control reads that resistance continuously. If the reading is impossible, for example because the sensor circuit is open, the control cannot tell whether the motor is safe and shows Error 51. The blender may stop or refuse to run. The sensor itself may have failed, but the same display appears if the control board misreads a good sensor, so the two cannot be told apart from the front. Overheating can also show up as a sensor problem, which is why the maker suggests letting the blender rest before trying again. If the number comes back after a rest, the reading is bad even with the motor cool, and the sensor circuit is the place to look. The motor is last on the list, only when a known good motor changes the result.
Affected models and control systems
Hamilton Beach Commercial HBH750, HBH755 and HBH850 blenders with the display. Other error numbers on these models mean different things.
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
- 51 on the display
- Blender stops or will not start
- Error returns even after the motor has cooled
Possible causes
Listed in Hamilton Beach Commercial's documentation
- NTC sensor and its leads open
- Connectors at the motor and control
- Control board input for the sensor
- Motor, if a known good motor changes the result
Other likely causes — what usually sits behind error # 51 on this control. A technician confirms which one it is before any part is replaced.
- Hot kitchen air that keeps the base from cooling between heavy blending jobs
- A lead pinched near the motor housing during an earlier repair
Safe checks before calling for service
- Unplug the blender and let it rest, since overheating can show up as a sensor problem.
- Plug it in again and see whether 51 returns.
- Make sure the jar sits properly on the base.
- If 51 returns, stop using the blender and call us.
- Tell us how long it was resting and what it was blending when the error appeared.
How a technician diagnoses error # 51
- Record the error and confirm it appears with the motor cool.
- Measure the NTC sensor resistance and compare it with the expected value at room temperature.
- Check the sensor leads and connectors for an open circuit.
- Inspect the control board input with a meter.
- Test with a known good motor if the sensor and board read normal.
- Replace the sensor or board only after the measurements point to it.
- Reaching the NTC means opening the base and working near the motor and live control board.
- An open sensor and a misreading board look the same on the display, so measurement is the only way to tell.
- Testing with a known good motor needs parts and tools we bring for the job.
Technical reference
- Document
- Hamilton Beach Technical Data Sheet GB34 HBH750/HBH755 (Doc 520008100 Rev B, 2024) and HBH850 (Doc 520004200)
- Edition
- Document # 520008100, Rev: B, revision date 05-Sep-2024 (Revised added Error 51 info); form ENG-FRM-RIC-4.32 Rev. E
- Models / control
- HBH750 / HBH755 / HBH850 display
- Section
- Trouble Shooting Guide, pp. 1-2 (error # 29/30/42/100/103 at end of p. 1 into p. 2; error # 60/62 and error # 51 on p. 2; Speed Sensor Failure/Error on p. 1)
- 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 Hamilton Beach Commercial blender error codes
Is Error 51 a hot motor?
Not necessarily. It is a bad temperature reading, and overheating is only one reason.
Can I keep blending?
No. The control cannot confirm the motor is safe while the reading is bad.
Will it clear after a rest?
It can if the cause was heat. If it returns with a cool motor, the sensor circuit needs a test.
Need help with Hamilton Beach Commercial error # 51?
A technician confirms the cause on site and gives you the price in writing before any work starts.