Waterproof system activated. close stopcock. The water system protection has reacted

My first reply to this question provides a fix, but doesn't affect the cause of the problem.

I had a specialist visit today for another reason, and he surprised me considerably by his solution to this problem.

First, he showed me how much dirt was in the washing machine even after 4 full rinses and 4 partial washes with no clothes in the machine. The water was black and thickish with lots of gunk in it!

Second, he showed me how much suds was in the machine still after those rinses and partial washes. The suds filled the drum!

He told me to descale the machine every 6 months with Cotton at 60 degrees Celcius (and 75 degrees C if not done for a long time); ours had not been descaled for 9 years. Serviceman asked me if I would not service my car for 9 years, and suggested I check the manual for maintenance procedures. I thanked him.

After descaling, do a Cotton wash (with no clothes) at 95 degrees C, using 1/2 of the recommended amount of powder as for a full wash.

Finally, he told me that we should use 1/2 the powder recommended on the packet for any wash. E.g. for a full load (100%) the packet might say use a full scoop - so use 1/2 a scoop. If the %age recommended by the washing machine is 60% and packet of powder indicates 1 1/2 scoops, calculate 60% * 1.5 = 0.9, i.e. 90%, of a scoop as usual - and then halve it, so 0.45, i.e. 45%, of a scoop. We were using too much powder, so we would not get a good wash because of all the suds.

He said this should fix the stopcock problem. My first reply to this question provides a fix, but doesn't affect the cause of the problem. I had a specialist visit today for another reason, and he surprised me considerably by his solution to this problem. First, he showed me how much dirt was in the washing machine even after 4 full rinses and 4 partial washes with no clothes in the machine. The water was black and thickish with lots of gunk in it! Second, he showed me how much suds was in the machine still after those rinses and partial washes. The suds filled the drum! He told me to descale the machine every 6 months with Cotton at 60 degrees Celcius (and 75 degrees C if not done for a long time); ours had not been descaled for 9 years. Serviceman asked me if I would not service my car for 9 years, and suggested I check the manual for maintenance procedures. I thanked him. After descaling, do a Cotton wash (with no clothes) at 95 degrees C, using 1/2 of the recommended amount of powder as for a full wash. Finally, he told me that we should use 1/2 the powder recommended on the packet for any wash. E.g. for a full load (100%) the packet might say use a full scoop - so use 1/2 a scoop. If the %age recommended by the washing machine is 60% and packet of powder indicates 1 1/2 scoops, calculate 60% * 1.5 = 0.9, i.e. 90%, of a scoop as usual - and then halve it, so 0.45, i.e. 45%, of a scoop. We were using too much powder, so we would not get a good wash because of all the suds. He said this should fix the stopcock problem.