wrote:
hi there

ok, I've taken off the lance altogether, where it screws into the
unit.

Switch on and the pump runs endlessly and very low flow rate dribbles
out of the
lance socket.

Sounds like either insufficient water supply or air getting into the pump.
Check the small hose going from the chemical valve to the pump inlet, make
sure the valve is closed & that all joints are tight.

Even a small air leak on the inlet side will cause those symptoms


There's a lot of air swirling around the pump casing. I
don't know if that's
usual, perhaps to cool it down? Or whether the casing's cracked and
there's some
sort of air leak?

That machine has an air cooled motor, so its probably that. The back of the
motor drives the blower for thr burner, usually through a flexible collar -
check that its tight or you burner will play up.

Water is constantly spitting out of the skinny transparent overflow
hose out of the top
of the cylinder head. Other than that, not much happening.

AFAIK there isn't an overflow on the cylinder head. Are you sure that isn't
the chemical inlet pipe (see above)? Position 38/39 here
http://www.sparesgiant.com/spare-par...~11701110.html
top right.



--
Dave - The Medway Handyman
www.medwayhandyman.co.uk