Hi all, I'm not an expert in plumbing. I'm having this problem with my washing machine. Sometimes it overflows out of the drain pipe.
1) My drain hose is about 45 cm long, and I inserted the full length into the drain pipe.
2) The flooding occurs during medium to heavy loads, >34 L.
3) During rinsing, the washer refills. I hadn't noticed it before but I've noticed it since the flooding started.
4) The flooding happens when I use more detergent than usual.

Can anyone suggest a solution?

Thank you.

Simple - the drain has a clog, or a narrowing of the pipe from years of accumulation hardening around the sides. I took out my kitchen 2" drain down to the cellar (cast iron) and the opening was down to the size of my thumb. Try drain cleaners several times, see if you can find a clean out (pipe that comes to the side with a removable plug), and buy a 'sock' to put over the drain hose that is specifically made for washers to collect lint. Flannel, terry, sweats, fleece, etc. produce tons of lint.

I've successfully unclogged it, and will be taking precautions as suggested above. Thank you very much.