George.com wrote:

Terry
Let me get this clear. You are saying that a 20m length of standard size
washing machine outlet pipe (the same diameter as I have on the WM
outlet) is too narrow?

If you just connect it up to the washing machine drain pipe, then water
will flow through it, but much slower that that it comes out now. The
pump out will take longer. Eventually you will, most probably. burn out
your washing machine water pump, if something else doesn't break first.



I am pumping about 900 mill above the bottom of
the WM tub, out a window and then a 2m fall off to the lawn below which
is flat.

Your opinion is that this set up will not work?

What I am saying is not to connect it directly to the drainpipe of the
washing machine unless you want to destroy the water pump.

If you want to understand how much extra work you will be making the
washing machine water pump do, make up your 20 metre pipe, drap both
ends over the back of a chair, fill the hose with water, then try to
blow all the water out of the pipe with your lungs.


If then I plump some form of surge tank (not being too sure what that is
yet but will find out),

The easiest way to explain how a surge tank works is to take that 20
metre hose you have have made up and put a funnel in the end. Then have
the washing machine pump out into the funnel.

It is almost guaranteed that the funnel is going to overflow, real fast.

A washing machine is designed to "pump out" in something like 2 minutes.
It will take the 2 metres of gravity a lot longer to force that same
water through the hose you are making up.

All a "surge tank" is is really just a bigger funnel. Big enough to hold
the excess water until gravity feeds it down the pipe you are creating.

Ideally, you want something that will hold the water that your washing
machine uses for a wash. How many litres of water does your washing
machine use?



am I having to rely on gravity (the drop off
from the deck to lawn is about 700mm) to draw water out of the tank and
on to the lawn

Yes. You do not actually want a big hose to water with as that can wash
soil, etc away.

or will the wm pump continue to do this?

I have collected myself about 20 mm of identical size concertina hosing
& some couplings.

Good score in any case.

I am set to go, apart from the somewhat important
matters like those above.

Thanks
Rob