Ariston Av1048C Not Advancing

[davehills]

My beloved Ariston AV1048CUK isn't working! It's quite an old machine but has proved reliable over the years so I'd like to repair it if I can.

The problem is that the timer sticks part way through the wash cycle. I'm pretty sure it's not the timer itself but the timer is waiting for a response from something else, which never comes.

On a wash cycle the machine fills to the correct level. It then heats the water, as I can feel the door getting warm. The machine then spins the drum correctly, as it would to to agitate the clothes.

It's at this point the timer stops; the machine just sits there agitating the clothes.

I'm thinking the water level sensor works OK and that the heating element is OK too. What else would cause the timer to stop at this point in the cycle?

Would a thermostat stuck in the 'on' position cause this problem without boiling the water? What other sensors are involved at this point in the cyle?

Any ideas?

[Whitegoodshelp (Andy)]

Old washing machines behave differently as they don't have error codes. If it's heating the water then it's waiting for the thermostat to close having reached the correct temperature before moving on. If the thermostat doesn't close it should overheat (more modern washing machines will usually abort and indicate an error code). Therefore it's a strange fault. If it definitely is heating the water it's possible limescale or a broken heater could be making the process so slow it's appearing to get stuck. Can you hear the water heating up like in a kettle? If so, but the water isn't that hot it could be the heater broken or heavily caked in limescale.

Alternatively it's possible the timer is faulty and just not reacting to the thermostat closing. I would definitely not attempt to replace the timer because it may well not be that and that would be a lot of time and money wasted.

[davehills]

Well, on a 40C wash, if you open the door you can feel that the water is warm.

On a 90C wash the water certainly doesn't boil so something is presumably limiting the temperature...

Is there perhaps a secondary 'safety' thermostat in series with the heater which stops the thing overheating if the primary thermostat fails?

PS: I have no plans to replace the timer if it has failed - far to scary a prospect!

[Whitegoodshelp (Andy)]

Hello Dave: No there's not usually a secondary cutout, which is why washing machines used to boil the water dry when the thermostat failed. If it's a hot and cold fill, could the water just be warm due to taking in hot and cold water?

[davehills]

I must admit I hadn't thought of that! D'Oh! Of course, the hot fill would make the water warm....

The wife managed to get the machine to work OK today, briefly, which caused some scratching of heads. How could it 'fix' itself before failing again?

Last night I switched the central heating boiler over to the winter setting, which increases the temperature of the hot water. What's the betting the incoming hot water is over 40C, which fools the machine into thinking the element is OK?