Dexter Dryer Error Code COMM ERROR1: Communication Bus Error
COMM ERROR1 means the control board has a communication bus problem. The manual says to power the machine down and try to reset the control, verify voltage and ground at the board, and replace the board if the error cannot be cleared.
Medium: the control board reports a bus problem and the dryer may not run until it is cleared or replaced.
What does Dexter COMM ERROR1 mean?
A control board talks to its own parts, and sometimes to other devices, over an internal communication bus. The board expects that conversation to run cleanly. If it detects a problem, it shows COMM ERROR1 with the message “COMM ERROR1 (Communication Bus Error)”.
The manual does not say which devices are on the bus or what exactly went wrong. It lists the same remedy as for the other control board errors. Power the machine down and try to reset the control. Verify the voltage to the control board and check the ground to the board. If the error cannot be cleared, replace the control board. Because electrical noise and a weak supply are classic reasons for communication trouble, the voltage and ground checks are not a formality. They are exactly where a technician would look before committing to a new board.
Affected models and control systems
Dexter coin-operated dryers with the electronic control. The document prints no model list, and it does not state which dryer sizes the table covers.
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
- COMM ERROR1 on the display
- The dryer will not start, or stops mid-cycle
- The message reappears after power is restored
Possible causes
Likely causes — what usually sits behind COMM ERROR1 on this control. A technician confirms which one it is before any part is replaced.
- Low or unstable supply voltage disturbing the bus
- Poor ground at the board
- Bus circuit on the control board damaged
Safe checks before calling for service
- Turn the dryer off, wait a minute and turn it on again, as the manual suggests.
- Note if COMM ERROR1 comes back right away or only later.
- Do not open the control cover.
- Tell the technician about any recent electrical work or flickering lights.
How a technician diagnoses COMM ERROR1
- Reproduce the message after a reset.
- Measure voltage at the control board.
- Check the ground connection.
- Look for loose or damaged connectors and wiring on the board.
- Replace the board if the error cannot be cleared.
- Checking supply and ground means live measurements in the cabinet.
- Electrical noise from nearby equipment can be the real cause and takes experience to trace.
- A replacement board needs correct model selection.
How COMM ERROR1 differs from similar codes
COMM ERROR1 concerns the communication bus. COMM ERROR2 concerns the model selection jumpers.
Technical reference
- Document
- Dexter Safety Guidelines / Common Dryer Troubleshooting Issues & Solutions / Troubleshooting Dryer Fault Errors/Codes (first-page headings; no separate cover title)
- Maker documentation
- Dexter owner support
- Models / control
- Dexter coin dryers with the electronic control; no model list printed (the T-30 to T-120 range is not stated in the document text)
- Section
- Dryer Error Codes table (Symptom / Probable Cause / Suggested Remedy), p. 6
- 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 Dexter dryer error codes
Is COMM ERROR1 the same as COMM ERROR2?
No. COMM ERROR1 is a communication bus problem. COMM ERROR2 means no dryer model is selected.
Could the building power cause it?
The manual makes you check voltage and ground first, so a supply problem is possible.
Will it clear itself?
A reset may clear it. If it comes back, the board may need replacing.
Need help with Dexter COMM ERROR1?
A technician confirms the cause on site and gives you the price in writing before any work starts.