Hoover New Wave Overheating

On the Hoover New Wave washing machines, the temperature should be controlled by a thermistor and not by an old fashioned standard thermostat. Thermistors are now commonly used instead of thermostats on computer or PCB controlled washing machines. I'd need a model number to check for sure if yours has a thermistor but I'm fairly sure it does. Thermostats (and now thermistors) have always been one of the most reliable parts on a washing machine and even after 29 years I've hardly replaced any.

A thermistor usually has heat sensitive crystals inside that change their electrical resistance as the temperature changes. This enables a PCB control board to know exactly what temperature the water is by the resistance reading. The old thermostats were simple bi-metal switches that closed (or opened) when a predefined temperature is reached.

With the old thermostats, each temperature was controlled by a seperate switch and it was possible for one temperature to go faulty on its own. I couldn't be 100% sure, because I've had hardly any trouble with them, but I wouldn't expect a thermistor to give false temperatures on some washes but not others. They only have two wires to them, and I would expect they will either work or not work.

If the washer is overheating only on the 50 degree wash this is unusual and I'd have to suspect the control module board, which is definitely not worth replacing on this washing machine.