washing machine waste pipe

[Hack]

hi,
I am relocating my washing machine and also the waste pipes. I want to tuck them into a corner and this involves the waste pipe going from 40mm down to say a 30mm pipe and then back to 40mm for the final run to the drain. Will going down a pipe size like this have any detrimental side effects eg water compression and expansion? I've no idea the quantity and force of a washing machine waste outlet...
thanks for any help.
Rob

 

[holty]

how much 32mm run?

 

[crockett]

I would just run it all in inch and a half. You may get problems with a build up of deposits where the fittings reduce from inch and a half to inch and a quarter.

 

[Hack]

hi, thanks for your replies,
The run of small pipe is literally minimal - less than 50mm I'd say. I want to locate this section behind some hot/ cold water pipes where there is a gap between the water pipes and the wall of about 30 - 35mm. this means that there will be a run of 40mm (incidentally is the measurement the inside or outside diameter of the pipe?) connected to an elbow join connector/ converter which will then join another elbow join connector/ converter to go back to 40mm. The gap between the two elbow joins means that they may actually be touching but I don't think there is anyway of joingin two elbow joins together without a section betwen the two? Ideally would like to run all at same but don't think I can squeeze it in.

I've looked at the existing pipes and there isn't really any buildup of deposits and we've been using it since we've been in the house (5+ years).
Thanks

 

[waterworks]

You can buy waste pipe elbows in what is called M&F which has collar one end and spigot the other.

 

[Hack]

that sounds good - do you know where I can get them? plumbase/ b&q?
just had a brief look but couldn't find them
thanks

 

[keepup]

Are you sure you need to go down to 30mm? Are the pipes you are running behind hidden? If so, and there is plaster on the wall, could you not just chase some plaster away from behind the pipes to allow the 40mm pipe work to get behind?... just a thought.

 

[Hack]

pretty sure I do yes - I think the plaster has stopped before it gets to this level but will have a look tonight.
At present all pipes are exposed but they will be hidden.
Good thought thanks!

 

[waterworks]

Should be able to buy M & F fittings in Plumbase but probably only in solvent weld type.

 

[keepup]

Should be able to buy M & F fittings in Plumbase but probably only in solvent weld type.

Hack, as waterworks says, 'Solvent weld'. I reckon this would be the best option anyway as the joint diameter is only about 8mm more than the diameter of the pipe. With push-fit/Compression joints the diameter at the joint is much greater and as your pipework will be VERY close to the wall i would think getting any other fitting on will prove difficult.

Hopefully you will be able to remove some Plaster to give you a bit more room to play with.