BUNN Slush Machine Message DEFROST: Barrel In Process of Defrosting
DEFROST - LEFT/RIGHT BARREL(S) IN PROCESS OF DEFROSTING means the barrel is in a defrost cycle. The machine returns to normal operation by itself after defrost is complete.
Low: a normal cycle message that clears on its own.
- Code
- DEFROST - LEFT/RIGHT BARREL(S) IN PROCESS OF DEFROSTING
- Maker
- BUNN
- Equipment
- Slush & frozen drinks
- Applies to
- Ultra NX frozen beverage dispenser
What does BUNN DEFROST - LEFT/RIGHT BARREL(S) IN PROCESS mean?
The Ultra NX dispenser runs a defrost cycle to clear ice that has built up on the barrel, and it shows DEFROST while the cycle is in progress. The Use and Care Guide says the barrel is in a defrost cycle and that the machine returns to normal operation after the defrost is complete. There is nothing to do except wait. The message is not a malfunction. During defrost the product in that barrel is warmed, so serving from that side may be soft until it refreezes. The guide lists no causes and no actions beyond waiting. If the message appears again and again, or never ends, that would be a different matter and worth a call, but the guide does not give a time limit for a defrost cycle. Because the defrost warms the barrel on purpose, it is normal for the product to look softer or a little thinner while it runs, and it firms up again once normal freezing resumes.
Affected models and control systems
BUNN Ultra NX frozen beverage dispensers. Other BUNN frozen drink machines use different messages.
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
- DEFROST on the display
- Product on that side softer than usual
- Barrel quiet while the cycle runs
Possible causes
Likely causes — what usually sits behind DEFROST - LEFT/RIGHT BARREL(S) IN PROCESS on this control. A technician confirms which one it is before any part is replaced.
- Defrost cycle in progress
- Defrost repeating because the barrel is icing quickly
- Low product level in the barrel
- Rear clearance blocked, making the machine work harder
Safe checks before calling for service
- Wait for the defrost cycle to finish.
- Avoid drawing product from the barrel being defrosted.
- Check that the hopper has product.
- If DEFROST keeps appearing, note how often and tell the technician.
How a technician diagnoses DEFROST - LEFT/RIGHT BARREL(S) IN PROCESS
- Confirm the message and the side.
- Observe the length of the defrost cycle.
- Check the hot gas valve operation.
- Check the barrel temperature sensor and torque readings.
- Look for causes of excess icing.
- The hot gas circuit is part of the sealed system.
- Sensors and valves are live control circuits.
- Repeated icing can point to airflow or product problems.
How DEFROST - LEFT/RIGHT BARREL(S) IN PROCESS differs from similar codes
DEFROST is a normal cycle message. Other messages report cleaning, product or sensor problems.
Technical reference
- Maker documentation
- BUNN owner support
- Edition
- 58028.0000 B 2/22
- Models / control
- Ultra NX frozen beverage dispenser
- Section
- Warnings & Error Messages table, side 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 BUNN slush & frozen drink error codes
Is DEFROST an error?
No. The machine is running a defrost cycle.
How long does it take?
The guide does not give a time. If it seems far longer than usual, or the message never ends, note the time it started and tell the technician.
Can I serve during defrost?
The product may be soft because the barrel is being warmed, so it is better to wait until the display returns to normal and the slush has refrozen to its usual texture.
Need help with BUNN DEFROST - LEFT/RIGHT BARREL(S) IN PROCESS?
A technician confirms the cause on site and gives you the price in writing before any work starts.