On Tue, 04 Apr 2006 11:48:56 -0700, Mary Hinge wrote:

Most definately working.

Air does tend to also get trapped on pipework around the boiler, since
the feed & return drop down 2m immediately before/after the boiler if
you get my drift, i just bleed these using the manual air vents?

Is it really necessary to have auto air vents wherever air tends to
accumulate to ensure all the air comes out of a sealed system? I sort
of assumed that after a short period it would just end up in the rads
where it can be bled out, leaving an air-free system.

My gut feeling is air is being pulled in around the area of the pump
inlet, is this possible and how common is it?

The whole system is under pressure. It is possible apparently for a system
to draw in air even though it is under pressure through small leaks.

The auto air vent is a convenience really rather than an absolute
necessity, it can even be closed once all the air is out.

If I were faced with the system professionally then assuming I haven't
missed anything in your posts then I would go for sealing it up with
Fernox LS-I or equivalent.


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html