Bosch Dishwahser water level sensing

[windy1]

Bosch 4002/13 FD 7905. ENR is SGS4002GB/13 Inlet valve operates several times in quick succession during fill cycle: seems confused about the correct water level. After filling, rest of cycle works fine.

Checked filters on inlet pipe and on machine are clear. Dismantled inlet valve, inspected the solenoid etc – all OK. Removed and cleaned the ribbed pipe going to the sump: some gunk there but not blocked. Cleaned a bit of gunk from the red valve at the top of the waste tubes. On the RHS of the machine, the clear plastic tube rising up into a loop is also clear.

Must be level sensor? Where is it? There are 6 clear plastic tubes ( 2 for waste) in the same moulding with intricate loops and a port open to the air. How is the water level detected? Is it a float, a timer or an air switch or a combination?

The red float switch and the air sensor tube with its blue operating rod don’t seem to be doing much, even though water can be seen flowing through the base. The microswitches click if pushed manually. There is no water in the base.

Any suggestions where else to check the waterlevel sensing is correctly set?

[superfix]

Re: Bosch Dishwahser water level sensing

windy1 wrote:the air sensor tube with its blue operating rod don’t seem to be doing much, even though water can be seen flowing through the base. The microswitches click if pushed manually. There is no water in the base.

There is your answer, blue rod operates the pressure s/w.

If sump hose is clear, then possibly the chamber below the s/w is gunged up.

Power off please if having a look.

[windy1]

Re: Bosch Dishwahser water level sensing

Thanks Superfix.

The tube leading to the air pressure diaphragm is clear. Removed it – blowing in that tube moves the blue rod which then operates the microswitch, so I can’t see any reason for the water level to bounce here?

If the air sensor is what senses the water level, what’s the purpose of the red float chamber and s/w right next to it?

[superfix]

Re: Bosch Dishwahser water level sensing

windy1 wrote:Thanks Superfix.

If the air sensor is what senses the water level, what’s the purpose of the red float chamber and s/w right next to it?

That is the overfill float. If the pressure s/w goes west then water will raise the float and bring the pump in.

[Author]

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