Washing machine drain hose

[bullethead123]

Hi all,
There's probably a very good reason why not but could I run a 1.5m extension to a washing machine waste water hose straight through the wall and straight into a 40mm wastepipe?
The hose would at all times be above the level of the top of the washing machine drum and have a slight downhill gradient before entering the 40mm pipe.
I guess I could add a 40mm trap outside the house (in an outside toilet) but I am concerned that this may block in freezing weather.
Thanks, Chris.

 

[Wayners]

You dont want the trap outside where it could freeze.
Probably don't need a trap

 

[CountryFan]

Probably don't need a trap

How are smells prevented from emanating?

@bullethead123 - possible to trap where it is and run a longer section of waste pipe?

 

[Wayners]

Washing machine pipe just drops in a open top 40mm waste so no smell from that.
Some washing machines are connected to a waste trap directly and they stink when taken apart but again no smell.
The only way you would get a smell is if there is a pressure of rotten gas pushing through the water held in washing machine pump. That's not going to happen if soil pipe is open or washing machine isn't used and dries out.
That's my theory

 

[bullethead123]

Thanks Wayners & Stuckinarut,
I guess I could put a trap in the cupbord next to the washing machine (it's an IKEA kitchen) but there's not much storage in the kitchen anyway - I'm loath to install unnecessary plumbing - and it would mean core drilling a lower hole as the current hole is too high if an inside trap is used.
Wayners, you say pop the end of the waste hose extension into a 40mm pipe, shouldnt I use a fitment to secure the hose to the pipe or is the open to the air method necessary.

 

[bullethead123]

Just re-read your post Wayners. I see why open to air is necessary.
Thanks once again guys.

 

[Hugh Jaleak]

Drain hose needs an air break at point of discharge. Correct method would be for hose to discharge into 40mm pipework internally and then the 40mm waste run to a suitable discharge point, e.g. stack or gully.

Options are either a standpipe or connection to a sink trap, either way the machine is discharging about the water level in the trap, the purpose of the trap is to seal off the downstream pipework and prevent foul odours coming back into the room.

I'd also check Appliance Manufacturers small print very carefully before extending a drain hose, many don't like it, and it may void the warranty.