Maximum washer waste extension

[pilchard]

I intend buying a new Samsung washer, possibly even a washer/dryer. The ideal new location in our small cottage is under the stairs, which then means the machine would be approx 5 metres from the open grey-waste gully outside. It would cause far too much pretty intense disruption to instal the normal 40mm waste pipe, but it would be possible to instal a smaller bore rigid waste system and still obtain the required 1:40 fall.

I am wondering if it would be acceptable to use a 21.5mm overflow/condensate solvent-weld pipe, requiring three elbows, and make a water-tight joint to the corrugated flexible hose. The hose is already clipped to and rises up the back of the machine and therefore creates it's own trap.

What might the guys in technical say?

[xSteveuk]

On waste its no much the length it's when on a upward slope - horizontal should be OK

[antikythera]

The waste outlet hose shouldn't be used clipped to the back of the machine and also smaller bore pipe could also lead to a build of excess pressure for the pump to work against. Have you not got an outbuilding you can put it in instead? I understand you don't want to mess with the cottage structure. As much as you may not want to use it still, the old location may be better if the waste facilities are already in place

[pilchard]

The recommended minimum height for discharge of the corrugated flexible pipe into a vertical 40mm waste-pipe and trap is 30", and that is why waste-hoses, despite emerging from the base of the machine, are invariably clipped to within a few inches of the top of the machine. This is designed to reduce the chances of water being unintentionally syphoned from the machine if the hose were laid down to discharge into an open drain or gully at floor level, to prevent smells emerging from the machine via the hose, and prevent small insects etc entering the machine.

I HAVE seen extension hoses up to 3.5 metres long, and although some of these have a bore size a little greater than the original, the turbulence created by the corrugations and the impossibility of achieving a perfectly straight inclining route would not just increase loading on the pump but provide greater dips bends and hundreds of additional crevices for deposits to accumulate. By trimming away excess length from the factory-fitted waste-hose and and making a permanent water-tight connection to approx 4 to 4.5 metres of the perfectly straight and smooth-walled rigid 21.5mm overflow pipe, I am assuming that the flow-rate this would permit might be at least as good as that achieved using even a standard flexible hose-extension.

 It's a small cottage, with no outbuildings, and it's a struggle to make best use of what little available space there is.  I am waiting until I can re-locate the washer to finish the final stage of the kitchen refurb, and the kitchen is small enough without the washer taking up valuable and limited space. The bathroom refurb is next on the list but, again, the washer would crowd that out too. The only logical position is the under-stair storage area which is adjacent to the bathroom separated by a 10cm block wall. The only way to get a 40mm pipe through the bathroom without compromising the limited layout options would be to dig a 4 metre long L-shaped trench through the cement-screeded  bathroom floor to a finishing depth at the outflow end of 15cm. Getting a narrow-bore pipe through the bathroom would be a much simpler proposition and not require excavating the floor to ensure a 1:40 fall.