I have just had a repairman tell me that my self-installed standpipe is too
low and causes the washing machine to stick on a fill-cycle.
His explanation, which was obviously what he has been taught, is that the
water enters the machine, fills the drainpipe at the back, which rises to
reach into the standpipe, and as soon as it reaches the top of the drain, it
spills over and starts 'siphoning' - which he immediately associated with
siphoning petrol ("not that I have ever done that" he pointed out)
My problem is - the fault is very interrmittent. On a rinse- cycle it lets
water in, and as soon as the level/pressure is great enough, it should stop
the intake, and move on to the next cycle. When the fault occurs, the drum
does not even start to fill before the water is escaping down the standpipe,
and it keeps on like that for hours, or until it is knocked-on.
For the water to reach the top of the standpipe to spill-over, there has to
be pressure behind it, and if the drum level is low or empty, that pressure
can only come from the inlet, and assumes that something is stopping the
inflow from getting to the drum, so it carries on to the outlet.
He tried to 'fix' the fault by raising the U-bend over the standpipe from
the recommended minimum (60cm) to 85cm - near the maximum of 90cm - just
under the worksurface, saying that he was confident that would do it.
On the first test, it was still spilling over, so he told me that it was
probably because it was still too low, and it was all the fault of the
'installation' of the standpipe (ie not his problem). If I replaced the
standpipe with a longer one, it would cure it. I tried to get him to
explain the difference between raising the drainpipe as he had done, and
increasing the height of the standpipe, and he tried to tell me all about
Young folk today!
He was also careful to get me to sign his paperwork _before_
filling in what
he had done (I didn't notice the blanks) so that "standpipe to low" (sic)
went in after I had signed! Damn!
Also there was a blank box saying "tick this box if you don't want your
details passed to third parties" double-damn!