Dexter Commercial Washer Error Code F5: Comm Error 2 Jumpers

What does Dexter error code F5 mean?

Despite its name, F5 (COMM ERROR 2) is not a cable problem. The controller on a Dexter VFD washer learns what machine it belongs to by reading jumpers: small links that set the washer size. Reading them at start-up lets one controller design serve the whole range of washers, each with its own motor size, fill levels and cycle limits. If the jumper pattern does not describe a valid washer, the controller does not know what it is controlling and will not run, and it shows F5. The washer will not start until the setting matches the machine. The maker notes this often follows a controller swap, since a new board may arrive with jumpers set for another size, or a jumper change by someone adjusting the machine. The maker also lists the harness connections and the drive size for the washer. A harness plug that is not fully seated can make a jumper read as open, and a drive that does not suit the size can bring the same message. Because the choice of jumpers depends on the exact model, a technician needs the full model number before any setting is changed.

Affected models and control systems

Dexter C-Series and T-series coin washers with a VFD, T-300 to T-1450, such as the T-450 Express.

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

• F5 (COMM ERROR 2) appears right at power-up
• The washer will not start any cycle
• The message appeared after a controller was replaced
• The washer displays normally except for the code

Possible causes

Listed in Dexter's documentation

• Washer size jumpers set wrongly on the controller
• Controller recently replaced
• Loose harness connections
• Drive size that does not suit the washer

Other likely causes — what usually sits behind error code F5 on this control. A technician confirms which one it is before any part is replaced.

• A replacement controller shipped with jumpers set for a different size washer
• A jumper pin that has worked loose or oxidized so the pattern reads wrongly

Safe checks before calling for service

How a technician diagnoses error code F5

1. Confirm F5 and read the model and serial number from the data plate.
2. Look up the correct jumper pattern for that washer size.
3. Compare the jumpers on the controller against the pattern and check each is seated.
4. Inspect the harness connections for loose or swapped plugs.
5. Confirm the drive horsepower suits the washer size.
6. Correct the setting, then run a test cycle to confirm the message is gone.

How error code F5 differs from similar codes

DRIVE ERROR 1 is also a size mismatch, but it compares the drive with the washer; F5 is about the jumpers the controller reads.

Technical reference

Document

Dexter Common Washer Troubleshooting and Error Codes (Washer Fault Errors, pp. 4-10)

Maker documentation

Dexter owner support

Edition

Part # 8533-***-*** 9/19

Models / control

Dexter C-Series and T-series coin washers with VFD (T-300 to T-1450)

Section

Washer Fault Errors & Codes, printed pp. 4-10 (PDF pp. 5-11); contents 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.