Andy Hall wrote in message ...
On Mon, 15 Mar 2004 23:14:31 GMT, Martin Angove
wrote:

Since dishwashers have some quite hot programmes, why is it that they
usually only have a cold feed? Washing machines rarely come without a
hot feed, why not dishwashers?



2) Modern dishwasher detergents are designed to work based on contact
time with the contents, whereas older detergents were essentially an
abrasive that was blasted onto the contents. Thus heating from cold
gives a longer cycle. It also allows machines to be designed to run
more quietly because they don't need such high pressure blasting the
contents.


For washing machines with modern detergents and fabrics, most washes
are fairly cool as well, so there is less and less need to fill them
with hot water either.


FWIW, I always plumb in the dishwasher on the hot supply, its fill water
only gets hot on the rinse cycles under normal circumstances( run
overnight). It's interesting to note that the Which tests on dishwashers
indicated that the results are only as good as the highest temperature of
the water. IMO, low temperature washing of dishes or white clothes is a PC
exercise, leading to poor cleaning standards actually being achieved. If you
want to see decent white cottons, boil them in Persil! When coloured
clothes are washed at low (30C) temperatures, the effect of the low
temperature detergents is frequently to degrade the dyes used and produce a
washed out look after only a few washes. Washing at 30C also does not kill
bacteria!!

Washing machines are starting to come with only cold feeds. This is a cost
reduction exercise, unrelated to how well they work!

Regards
Capitol