JURA X9 HEAING UP ERROR – by Guest Technician

Machine: Jura X9

Fault: Machine always displaying “MACHINE HEATING UP” after the welcome screen and never progresses any further.

Upon opening the machine and operating the micro switch that turns the machine off when the back cover was removed and an alligator clip on the water sensor connector, I found that the steam heater was cold, but no voltage was measured across the terminals. Upon further research I found that there were thermal fuses, designed to open circuit (permanently) if the thermal block got too hot, to avoid starting a fire.

These were available from the local electronics shop (Jaycar if you’re in Australia) and is a 216 deg C fuse.

The problem I was wrestling with is why did the fuse blow, was it just old age and multiple heat cycling or was it something else that would cause it to overheat again. The problem became clearer when bypassing the fuse (for testing purpose only), the machine came up with an “ERROR 4” which disappeared with moving the wires, but came back again permanently later after replacing the fuse.

The thermistor measured open circuit and I believe it was this in its early stages of failure that caused the overheat issue. As the resistance drops when the temperature increases and a higher value of resistance would cause the machine to overheat the block.

Not sure of what actual thermistor was being used (as the wrong type would cause invalid heat readings) I got the new part from Outwest Coffee Machines, (who just happens to be a couple of k’s down the road) at a good price.

Having replaced fuse and sensor, I am now back to drinking nice coffee.

Graeme

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