BUNN Slush Machine Message LEFT/RIGHT REFILL ERROR: Hopper Lights Flashing
LEFT/RIGHT REFILL ERROR with the hopper lights flashing is a refill error on that side. Press the Left Dot button for 3 seconds to clear it.
Low: it clears with a button press, but a repeat points to a refill problem.
- Code
- LEFT/RIGHT REFILL ERROR (Hopper Lights Flashing)
- Maker
- BUNN
- Equipment
- Slush & frozen drinks
- Applies to
- Ultra NX frozen beverage dispenser
What does BUNN LEFT/RIGHT REFILL ERROR mean?
The Ultra NX dispenser refills the barrel from the hopper, and the control watches that the refill takes place. When it does not see a normal refill on the left or right side, it displays LEFT/RIGHT REFILL ERROR and flashes the hopper lights. The Use and Care Guide's table gives one action: press the Left Dot button for 3 seconds to clear it. The guide does not list causes. The related message HOPPER LIGHTS FLASHING by itself means the hopper is low on product. The refill error is about the refill process, so after clearing it you should check that the hopper has product, the Autofill bag-in-box is not empty if you use one, and the line is not kinked. If the error comes back right after clearing, the refill is not working and the next step is service. The hopper lights tell you which side to look at. During the busiest hours of a hot afternoon, when drinks are drawn quickly, the barrel can empty faster than the refill keeps up, which is worth keeping in mind before assuming a part has failed.
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
- LEFT or RIGHT REFILL ERROR on the display
- Hopper lights flashing
- Barrel level dropping
Possible causes
Likely causes — what usually sits behind LEFT/RIGHT REFILL ERROR on this control. A technician confirms which one it is before any part is replaced.
- Bag-in-box empty or its line kinked
- Product too thick to flow into the barrel
- Refill valve not opening
Safe checks before calling for service
- Look at the hopper and the product supply for that side.
- Refill the hopper or replace the bag-in-box if needed.
- Press the Left Dot button for 3 seconds to clear the error.
- If the error returns, note which side and tell the technician.
How a technician diagnoses LEFT/RIGHT REFILL ERROR
- Read the message and note the side.
- Check the product supply, line and fittings.
- Check the refill valve or pump operation.
- Check the level sensing in the barrel.
- Replace the failed part.
- Refill valves and pumps are electrically driven.
- Product lines hold pressure and sticky product.
- The level sensing is part of the control circuit.
How LEFT/RIGHT REFILL ERROR differs from similar codes
The refill error needs a clear. HOPPER LIGHTS FLASHING alone means low product and clears when refilled.
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
How do I clear it?
Press the Left Dot button for 3 seconds. Hold it for the full time, since a short tap may not register, and watch the hopper lights to see that they stop flashing.
Is it the same as HOPPER LIGHTS FLASHING?
No. That one means low product.
What if it returns?
Then the refill is not working as it should. Write down the side, how soon it came back and the state of the hopper, and have the dispenser serviced instead of clearing it again and again.
Need help with BUNN LEFT/RIGHT REFILL ERROR?
A technician confirms the cause on site and gives you the price in writing before any work starts.