I've had a small 'tabletop' dishwasher for a couple of years now, I would have a full size one, but there just isn't space. It works, and I love it, at least it used to work...

Recently it started throwing up error code "E1" at the very start of a cycle. Reviewing the manual showed this meant:

Longer inlet time - A flow meter, drain valve, or pump failure, it should be repaired by a qualified worker.

This wasn't super helpful so I searched online. That led me to this video in which I learned that most of these mini dishwashers are manufactured by the same company, given a different look and branded.

What was really helpful was that he linked to the service manual.

Service Manual

The service manual included all the details, from circuit diagrams to part lists and some pretty cool exploded diagrams, which reminded me of the 'how it works' books I had as a kid. It also expanded on the meaning of the "E1" error code:

During the water inlet step, if the flow meter can't detect the defined water after 4 Minutes, or can’t detect 30 pulse after 60s, the dishwasher will warning for E1.

Something was up with the flow meter...

I took the back off revealing the flow meter, nothing was obviously wrong, no loose cables, but it was pretty hard to see. While pondering if I had the time to take it completely apart before dinner, it occurred to me that a flowmeter is a moving part and the whole water tank had become white with limescale. Moving parts and limescale don't mix well, I theorised that the impeller in the meter had become caked in limescale.

I added a warm citric acid solution into the empty tank and let it sit for 10m. I then forced it to drain the tank (hold Hygiene and Rapid for 3s), which would flush the solution through the meter.

I needed to do this twice because after one successful cycle it gave the same error again, but it's now happily saving me from having to hand-wash the dishes again.