"Rob Horton" wrote in message
...
As you can guess from the title, I have a Y-Plan central heating
system.
The 3 way valve controller has a lever on it and there appears to
be two
positions for it to be in. Left, marked as Auto and right, marked
as Manual.
For some reason (probably by mistake by the previous owners) the
lever
has always been at a position midway between Auto and Manual.

Dumb question I know, but what is the difference between Auto &
Manual?
When I experimentally move the lever to Manual it feels like there
is
some internal gearing that is being moved as there is slight
resistance
to motion.

The only instructions that I can find on the web are how to install
Y-Plan systems. What I want to know is how to operate the system
and why
I should want Manual instead of Auto and vice-versa.

Incidentally, I have noticed that when the hot water comes on but
not
the central heating, some of the radiators that are close to the
hot
water tank and the central heating control gear, heat up. Could
this be
a symptom of the (presumed) incorrect setting?


Yes, the valve should be set to auto, manual is used for testing, and
maintenance (draining etc) - water is being allowed to flow through
both the HW and CH irrespective of what the control system is calling
for.

It is possible that the valve is faulty, not uncommon, and the lever
has been purposely set to allow the system to work.