Hobart Legacy+ Mixer Error OH1: Drive Overheated
OH1 on a Hobart Legacy+ HL800 or HL1400 mixer means the motor drive heat sink went above 194 F and the drive shut the motor down. Let the mixer cool with the guard closed, clear dust from the outside of the bottom cover vent with the mixer unplugged, and move it away from heat if you can. Cycle power, and call us if OH1 comes back.
High: the drive shut down on heat, and running it hot again can shorten its life.
What does Hobart error code OH1 mean?
The drive turns electrical power into motor control, and it gets hot doing it. A heat sink on the drive carries that heat away to the air passing through the bottom vent. The drive senses the heat sink temperature, and above 194 F it stops the motor to protect its electronics and shows OH1 on the SmartTimer. The mixer will not run until power is cycled and the cause is corrected. The drive is rated for a room no warmer than 122 F, so a hot bakery or a spot near an oven makes this more likely. Flour dust, lint or grease in the bottom cover vent and on the heat-sink fins cuts airflow and makes it worse, and long heavy batches run back to back add heat faster than the drive can shed it. The drive can be clean and still overheat from a hot room or a failing fan. The fins sit inside the machine, so cleaning them is not a job for the owner. The display text is OH1.
Affected models and control systems
Hobart Legacy+ HL800 and HL1400 mixers with the motor drive and SmartTimer display. The drive is rated for rooms up to 122 F.
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
- OH1 on the SmartTimer display
- Mixer stops after long or repeated heavy batches
- Warm air or dust at the bottom vent
Possible causes
Listed in Hobart's documentation
- Bottom cover vent blocked by flour dust, lint or grease
- Heat-sink fins on the drive clogged
- Room temperature around the mixer
- Long heavy batches run back to back
Other likely causes — what usually sits behind error code OH1 on this control. A technician confirms which one it is before any part is replaced.
- A drive fan that has slowed from dust and moves less air than it should
- A mixer placed against a wall that blocks the bottom vent intake
Safe checks before calling for service
- Stop the mixer and let it cool with the bowl guard closed.
- Look at the bottom cover vent and clear dust from the outside of it with the mixer unplugged.
- If the mixer sits near an oven or fryer, move it to a cooler spot if you can.
- Cycle power. Call us to schedule service if OH1 comes back.
- Tell us the room temperature and how many heavy batches ran before the code.
How a technician diagnoses error code OH1
- Read OH1 and note the room temperature and recent batch load.
- Inspect the bottom vent and heat-sink fins for dust and grease.
- Check that the drive cooling fan runs freely and at the right speed.
- Compare heat-sink temperature during a run against the 194 F limit.
- Clean the fins with power isolated and confirm unobstructed airflow.
- Replace the fan or drive only after cleaning and ambient heat are ruled out.
- The heat-sink fins sit inside the machine, and reaching them means opening a drive that holds charge and line voltage.
- A drive can be clean and still overheat from a hot room or a failing fan, which takes a temperature test.
- We check airflow, the fins and the drive, and give a written price first.
Technical reference
- Document
- Large Capacity Mixers Customer Maintenance Manual F48065 (10-22), Diagnostic Error Codes
- Maker documentation
- Hobart owner support
- Edition
- F48065
- Models / control
- Legacy+ HL800 / HL1400 motor drive + SmartTimer display
- Section
- Diagnostic Error Codes HL800 & HL1400, PDF pp. 9-11
- 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 Hobart mixer error codes
Is OH1 a hot room problem?
Often, since the drive is rated for rooms up to 122 F. Dust in the vent also contributes.
Can I vacuum inside?
No. Clear only the outside of the vent with the mixer unplugged.
Will it clear when it cools?
Usually, but the same conditions bring it back.
Need help with Hobart error code OH1?
A technician confirms the cause on site and gives you the price in writing before any work starts.