I'm at my wits end with this fridge! It has started to run constantly (compressor NEVER stops) and ices up inside. I assumed it was a faulty thermostat and fitted a replacement - no difference! The capillary is 1200mm and disappears into a long sleeve within the machine so no way to check that it's correctly sited. To make sure I hadn't received a faulty replacement I tried another thermostat I had handy with a shorter capillary. This time I simply taped the capillary to the inside of the back wall and tried that - again, no difference - the compressor never stops. I left it for a few weeks and the ice built up so that eventually my temporary thermostat capillary became frozen in the centre of a huge block of ice. Even after that however, the compressor still refuses to stop!! The fridge wiring is correct (nothing's been touched from new) and the machine turns off when the thermostat knob is turned to off.

This fridge is a simple design - auto defrost controlled entirely by the Ranco K59 thermostat - no heater in the condenser, no separate stat, thermistor or PCB of any kind.

My first thought was that there's something amiss down in the sleeve for the capillary so the thermostat isn't sensing the temperature but then why would my 'other' thermostat not cut out with its capillary frozen in a block of ice?

As far as I can see the compressor is working normally but just not receiving a signal from the stat to cut out but surely two replacement stats can't be faulty?

Could there be some anomaly in the coolant circuit causing a blockage or air bubble at the point where the thermostat capillary senses the temperature? I'm almost tempted to turn the machine upside down then back again to see if that redistributes the coolant - would that do more harm than good?

Can anyone throw any light on this weird machine?