Blakeslee Commercial Dishwasher Error Code B4: Rinsing Failed
B4 RINSING FAILED means the final rinse did not take place as it should. The manual says to contact Technical Service. Stop washing, note the display, and have a service technician check the rinse circuit.
High: the machine cannot finish its final rinse, so it should not be run.
- Code
- B4
- Maker
- Blakeslee
- Equipment
- Dish machines
- Applies to
- D-18D / D-18V digital-control door-type
What does Blakeslee error code B4 mean?
At the end of each wash the machine sprays clean, hot rinse water from the boiler over the dishes. The control expects the rinse to start, run for its set period and finish. If something prevents it, the control interrupts the cycle and shows B4 RINSING FAILED. The manual lists the entry as rinse failed and gives Contact Technical Service as the only action. Unlike B1, B2 and B3, the wording does not name the boiler, the probe or the heater, so the alarm describes the outcome rather than a single part. It can come from a rinse supply problem, a rinse pump or valve that did not operate, or a blocked rinse path. Because the final rinse is what sanitizes the dishes and carries away detergent, the machine should not be used with this alarm active. The display text is B4 RINSING FAILED.
Affected models and control systems
Blakeslee D-18D / D-18V digital-control hood-type dishwasher. The manual's cover prints D-19 L and D-19 LRS and names no D-18 model, so the alarm list is read as covering this hood-type family.
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
- B4 RINSING FAILED on the display
- Little or no rinse water sprays at the end of the cycle
- Detergent film left on glasses and plates
- Cycle stops before it completes
Possible causes
Likely causes — what usually sits behind error code B4 on this control. A technician confirms which one it is before any part is replaced.
- Rinse water supply interrupted before the boiler
- Rinse valve or pump that does not operate on command
- Rinse nozzles or manifold blocked with scale
- Rinse boiler empty or not ready when the rinse is called
Safe checks before calling for service
- Switch the machine off and on once and run an empty cycle only if no other alarm shows.
- Look at the water supply valve and make sure it is fully open.
- Check that the rinse arms and nozzles you can see without tools are not clogged.
- Stop using the machine if the alarm returns.
- Note when in the cycle B4 appears and what the rinse looks like.
How a technician diagnoses error code B4
- Read the alarm history and see whether a boiler alarm preceded B4.
- Check the supply pressure and the strainer at the machine inlet.
- Observe a rinse request and confirm the rinse valve or pump receives its command and voltage.
- Inspect the rinse arms and nozzles for scale and clean them.
- Confirm the boiler is full and hot, then replace the failed valve, pump or sensor.
- The rinse circuit combines pressurized hot water and line-voltage valves or pumps.
- Finding which element failed means observing the machine while it runs with panels removed.
- Descaling and part checks need the right tools and know-how to avoid damaging the boiler.
How error code B4 differs from similar codes
B4 describes the result, a failed rinse. B1 to B3 and B5 name the boiler fill, probe, heating and overheating.
Technical reference
- Maker documentation
- Blakeslee owner support
- Edition
- COD. 3100ET_U, Ed. 06 - 09/2018
- Models / control
- D-18D / D-18V digital-control door-type
- Section
- Chapter 8.2 Alarms, table 3 (p. 39)
- 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 Blakeslee dish machine error codes
What does B4 tell me that B1 to B3 do not?
It reports that the rinse itself did not happen, without naming which part caused it. A technician finds the part.
Can I hand-rinse and keep going?
Hand rinsing will not replace the machine's hot rinse. Wait for service.
Did a missing delivery of water cause it?
It can. Check the supply valve first, as the water is the simplest cause to rule out.
Need help with Blakeslee error code B4?
A technician confirms the cause on site and gives you the price in writing before any work starts.