Quick one, just so it's recorded on the Internet somewhere. Hopefully save someone from an expensive call out, or a dishwasher from the bin.
My two year-old Indesit DIF16B1UK dishwasher that came with the house suddenly had a fault where a wash cycle would start but error out a few seconds after filling starts. It would then fill to the max, drain completely, start filling, error alarm, fill to the max, drain... etc over and over.
Error beeps are three beeps, followed by a single beep every few seconds.
All six green mode lights would blink, the salt and rinse aid lights remain off.
I opened up the left panel (facing the dish washer head on), the right panel doesn't need to come off.
Towards the back is a translucent plastic component, the bottom of which has a tiny circuit board that measures flow by detecting the magnet on the turbine, inline with the mains water inlet behind it.
In my case, the reed switch contacts were corroded. Taking the circuit board out of the translucent plastic enclosure, and testing the resistance across the reed switch, using a magnet to close the contacts, showed high resistance when closed.
To verify, I used a jumper wire to short the connection to the circuit board, I mimicked the expected open-close behaviour or the reed switch being magnetically actuated by the turbine, basically opening and shorting the jumper intermittently. While doing this, the dishwasher filled normally, and when I stopped, the dishwasher would give me the error beeps.
Confident that I've made the correct diagnosis, I searched for the correct part and found the translucent plastic assembly is a common spare part
"Indesit dishwasher air break turbine" part no. C00256546
I couldn't find the circuit board on its own. I didn't have any reed switches in inventory and figured the safest thing to do would be to order the whole C00256546 assembly since it wasn't too expensive and comes with the circuit board. Decided to go for a non-genuine part, fairly simple bit of kit, very little to go wrong and half the price of a genuine one. I paid £16.75 delivered on Ebay.
A useful tool to have is a slip joint plier with jaws that can do around 80-100mm - use this to grip the plastic lock ring in the inside of the dishwasher to unscrew and release the air break turbine assembly. Don't forget to clean the sealing surfaces between the assembly and dishwasher before you attach the new part (under where the sealing ring goes), lots of crud accumulates here.
You'll also need a new 18mm-ish hose clip, a jubilee clip works well, to replace the old hose clip on the inlet hose which is one-time use and no good after removing it.
Put it all back together, run a test cycle, check for leaks. etc