Why open stand pipe?

[shadrack]

I am re-positioning a washing machine and have sawn off and extended the existing 32mm washing machine drain pipe by 1.5m, routing it round a couple of corners and finishing with a 45 degree open pipe at a height of about 700mm or so. Unfortunately I now find that when the machine empties there is always a splash of water back out of the pipe - I guess it is because I have increased the resistance to the flow of water, and so the pipe backs up temporarily.

I assumed that an easy fix would be to fit a spigot-type hose adaptor at the end of the pipe (and finding the right combination of fittings is proving harder than I expected!), but most people seem to advocate the open pipe scheme. Why? With an open pipe if a blockage develops the machine will flood the room, whereas with a watertight hose adaptor nothing will happen. Or is there more to it than that?

 

[Diyisfun]

I think if there is a blockage the machine will know there is & stop pumping. My machine is connected very much as you have described & I have not had any problems.

 

[bathjobby]

finishing with a 45 degree open pipe at a height of about 700mm

Have you really got the 32mm drain pipe terminating at an angle of 45 degrees rather than vertical ? Make it vertical and you'll solve your problem.

 

[Gees]

An "air Break" is by far the best method of draining a washer / dishwasher to the outside world. It prevents any back syphoning of dirty water into the appliance. A vertical section of pipe 8 - 10 inches long is all you will need to prevent any splashback.

As for the pump stopping if there is a blockage.... don't you believe it.!!