Middleby Marshall Oven Alert High Control Compartment Temperature
High Control Compartment Temperature on a Middleby Marshall PS640 or PS670 means the front fan filters need cleaning or replacing. Left dirty, the oven shuts down on excessive temperature in the control compartment. Power the oven down, let it cool, and clean the filters.
Medium: the oven will shut down if the filters are not cleaned.
- Code
- High Control Compartment Temperature
- Maker
- Middleby Marshall
- Equipment
- Pizza ovens
- Applies to
- Middleby Marshall PS640 / PS670 touch-screen controller (screen alert)
What does Middleby Marshall High Control Compartment Temperature mean?
This alert is the stronger warning that follows Control Over Temp on a PS640G or PS670G. The control compartment at the front holds the electronics, and air pulled through the front fan filters keeps them from overheating. When the filters clog with flour, grease and dust, airflow drops and the compartment temperature rises. At this level, the controller is telling the operator that this is the last chance to clear the filters before the oven stops on excessive temperature. If it is ignored, the oven shuts down in the middle of service, which is much more disruptive than ten minutes spent on the filters. The manual's remedy is to clean and replace the filters. It is also worth checking that the oven has open space around it for air, because an oven pushed into a corner can overheat its controls even with clean filters. If the alert returns after cleaning and with good clearance, the compartment cooling fan or the temperature sensing needs a technician's check.
Affected models and control systems
This applies to Middleby Marshall PS640 and PS670 conveyor ovens with the touch-screen controller, such as the PS640G and PS670G. Other controller generations use different compartment alerts.
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
- High Control Compartment Temperature on the touch screen
- A hot front panel near the controls
- Filters visibly packed with dust or flour
- Oven shutting down if the alert is ignored
Possible causes
Listed in Middleby Marshall's documentation
- The front fan filters
- Airflow through the control compartment
- The cooling fan in the control compartment
- Clearance around the oven
Other likely causes — what usually sits behind High Control Compartment Temperature on this control. A technician confirms which one it is before any part is replaced.
- Filters that were cleaned once but are past replacement age
- Oven installed too close to a hot fryer or range
- Cooling fan inlet blocked by stored boxes or towels
Safe checks before calling for service
- Power the oven down and give it time to cool fully.
- Clean and replace the front fan filters, as the owner's manual lists.
- Make sure there is open space around the oven for air.
- Restart the oven.
- If the alert returns, note how long the oven ran first and call us.
How a technician diagnoses High Control Compartment Temperature
- Read the alert and check the filter condition.
- Check clearance and nearby heat sources.
- Confirm the control compartment fan runs.
- Measure compartment temperature against the controller reading.
- Inspect air paths for restrictions.
- Replace the fan or sensor only after the test.
- The control compartment contains live wiring and hot parts that should not be opened by staff.
- Compartment temperature has to be measured with a thermometer against the controller reading.
- A failing fan and a misreading sensor look alike from the outside.
How High Control Compartment Temperature differs from similar codes
Control Over Temp is the earlier alert for the same problem; this one comes when it is nearer to shutdown.
Technical reference
- Document
- PS640G I&O Manual 60251 Rev J, screen alerts
- Edition
- P/N 60251 rev J, (c) 2023 Middleby Marshall Inc.
- Models / control
- Middleby Marshall PS640 / PS670 touch-screen controller (screen alert)
- Section
- Section 3 Operation - Quick Reference: Troubleshooting, Screen Alerts table, printed p. 28
- 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 Middleby Marshall pizza oven error codes
How long do I have before the oven shuts down?
The manual gives no time. Treat it as the last chance and clean the filters now.
Can I clean the filters while the oven is hot?
Let it cool fully first, as the oven and compartment are hot.
Why does it return after cleaning?
The fan or the temperature sensing may need a technician's check.
Need help with Middleby Marshall High Control Compartment Temperature?
A technician confirms the cause on site and gives you the price in writing before any work starts.