I have an older Bosch compact dishwasher - Classixx Maxx Freedom Performance.

I installed it myself simply by mirroring the plumbing on the washing machine nearby - cold water supply and drain through a high loop to the drain.

enter image description here

It worked fine initially, but now has stopped filling correctly. I can hear the pump chugging away, sucking at air. Suspecting an air gap, if I pour a few jugs of water into it, the machine runs correctly.

  • What can cause an air gap in a dishwasher to form?
  • What other failures or installation mistakes could cause the dishwasher to fail in this way?

Edit: After thinking I had searched everywhere, I found the serial number etched on the inside of the door - it wasn't visible in most light. Serial number plate

The plate reads:

E-Nr: SR543002GB/20

FD 8310 000470

There is also this long number:


Here is the bosch support page:


Further info - a rinse cycle will work fine. The issue seems to be happening only when I put it on for a wash.

  • Please post the model # and serial # of the unit. Often found on a placard on the inside of the door or on the frame behind the door. Nov 2, 2019 at 16:07
  • The only number I can find on the machine is 5600041012/03/273/15:48. It was behind the machine near where the electricity cable enters the machine.
    – peteretep
    Nov 4, 2019 at 14:33
  • Feeling rather stupid and blind! Serial number exactly where you said it would be. Question updated with details.
    – peteretep
    Nov 11, 2019 at 19:45

1 Answer 1


Check the water level float switch. This is a device that dishwashers use to control the water fill level (to prevent flooding). It is most often located on the bottom (floor) inside, and usually has a "cap" looking float. When you turn on the unit, the float circuit allows the water inlet to open if (and only if) the float position indicates that the water level is less than full. When the float position indicates that the water level is full, it causes the water inlet valve to close and remain closed until the level is less than full.

A malfunctioning float, float switch, float circuit can cause water level/fill issues. It is not uncommon for them to get "stuck" or get "sticky". Fancy units may use a different type of water level control scheme, like a hidden float or a photo-electric sensor.

Look (real hard) for the label with the model number, it should look something like this:

enter image description here

  • Obviously, this answer presumes that you have already assured that there is no restriction or interruption of water supply to the unit... Nov 2, 2019 at 16:08
  • Thanks Jimmy. There is no sign of any sort of sensor on the bottom of the machine.
    – peteretep
    Nov 4, 2019 at 14:37

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