Hotpoint WF860 turns off/on and display flickers on heating

[absoft]

My WF860 washing machine has developed a fault whereby whenever it is heating the water, after 2 to 3 minutes, the entire machine switches itself off. If left the display will flicker on/off a few times and then it will turn back on and continue to heat the water but only for a short time before turning itself off again. If left long enough, the water does come up to temperature but with it turning off all the time it takes forever. A rinse and spin program works fine.

I have taken the control board out and checked for dry joints and domed capacitors but there are no problems. I changed the 680mF capacitor (though on this board it is not C17) for good measure too; still no joy.

Should I try a secondhand control module or does anyone know what the problem might be?

 

[absoft]

Is it possible that the heating element could be partially faulty and causing this e.g. it heats up and causes a short but the washer electronics shutdown and cut the power before the mains trips? No fault codes are ever displayed though once the machine comes on again. Anyway to test the element? I know it is still heating.

 

[absoft]

I tested the heating element with a meter, it's fine. Then I disconnected the machine connections from the element terminals and instead wired them up directly t the mains via a seperate lead and plug.

Then I ran a test wash with me turning on the power to the heating element manually. That all ran fine, the machine progresses through the cycle with no problems.

So I guess either the heating part of the control board has a problem or else when the heating element is in circuit, something just cannot handle the total current the machine is asking for.

I understand that a secondhand control board probably won't work as they are programmed to specific machines. A new one plus programming costs over £200 so just not worth it. It might not even be the board if something is limiting the available current to the machine.

Any ideas anyone?

 

[rocks1]

Set the mc to start once it fills unplug the top pcb. And let the mc run if it don't cut out then top pcb is faulty.

 

[absoft]

Well after 2 days of dismantling, taking both control boards out, connecting up the heating element independently and pulling the machine in and out of the fitted kitchen a gazillion times its looking like its........the mains socket switch !!! I don't think it can handle the current with the machine plus heater going. I plugged the machine into a different mains outlet and its running fine! Honestly, we were on the point of forking out for a new machine.

I can't say that's definitely it, need to run a few more washes yet but seems like its OK now.

 

[kbdiy]

In that case, turn off the power at the CU and remove the offending socket faceplate. Quite possible it has developed a loose connection. Check the wires are fully located in the terminals and screwed up tight.

 

[absoft]

Will do but its a switch for a spur and its grouted in. I think it is the switch contact itself opening up when it gets hot but will have a look and let you know. Its an awkward one to get to and I know there's no slack with the wires.

 

[absoft]

I dug out the 20A DP switch which was grouted in. The incoming live connection had partially melted and the 'copper' on the switch looked badly oxidised/corroded. The incoming wire is aluminium; don't know if that didn't like the 'copper' that MK had used. I have replaced it with a Crabtree switch which had much brighter looking contacts and seemed an altogether better design than the MK one.

The Crabtree has bright, shiny 'brass-looking' contacts and the screws are vertical which are ideal when the wires are short. The MK has duller copper/alloy looking contacts and the screws are angled towards the wall which is hopeless when there is not much of a gap!