"Lee Blaver" wrote in message
...
Gavin Gillespie wrote:


Washing machine outlet hoses should not go into a sink syphon, but
into a 1.5" standpipe, as per most instruction books. There are
several good reasons for this, including to prevent waste
water/grease
from the sink, flowing back into the machine, also any
restrictions in
the pipe, i.e. the joint where it attaches to the syphon, provides
the
perfect place for a loose button/any build up of fluff etc. to
block
the hose, and cause problems later on.
If a connector with a non return valve is used, this is worse than
ever, as it will block 10 times as quick.

If you must use a washing machine without a proper filter than I
suppose
you're right
The non return valve on the end of our machine's 2.5m waste hose has
not
blocked in the 3 years it has been there...


But most washing machines made now, do not have a fine filter, (more
of a coin trap), so any small items are supposed to be flushed through
the hose, which is OK if the hose is not restricted. Most of the
blockages at non return valves that I attended, had actually had the
'valve' removed by plumbers when fitting, but they had left the valve
fitting assembly (a bit like a cross gun sight), and these would often
block. One woman that I visited, would regularly pour hot chip fat
down the sink, this would flow down the washing machine outlet hose,
and solidify in the pipe, it must have cost her more than the machine
in repairs, but she never moaned about it.