[gertlex]

I bet some manufacturers don't even use temperature sensors in many models, and just assume an approximate incoming water temperature, and heat for a fixed time period according to calculations on amount of water in the system. This guess comes from the impression that cheap temperature sensing circuitry isn't the most reliable long-term.

[flowerthoughts]

How did you conclude that they aren't the most reliable long-term?

Temperature sensing is extremely simple and cheap. Bi-metal contacts have been used since the dawn of electronics, and the solid state versions are also really simple. (Making components that are temperature invariant is the hard task.)

[gertlex]

Fair question! My speculation here comes from thermistors being relatively common replacement parts. (clothes dryers, ovens) As you mentioned, temperature-invariant is tricky, and I think it's often a non-linear but close-enough for the design. I have the impression a failure mode can be if the temperature-response behavior changes over time.

A bi-metal contact is only good for a single temperature, I think? (can be adjustable like thermostats) (I'm sure many but not all dish-washers probably do only need a single temperature...)

[robocat]

I bet you're wrong. Is there a website where we can make an adjudicated bet JUST against each other. How many dishwashers come without a hot-wash option? Any dishwasher that didn't heat water enough would struggle with hard fats.

My dishwasher has a scalding 75°C option.

[protolyticmind]

If true, that is a recipe for a lawsuit if it went wrong.