Just to follow up my own post,

(Keith Refson - real email address in signature) writes:

I have posted before about the wonderful Servowarm gas CH system I
inherited with the "new" house, but now as I am preparing to upgrade
the controls and pipework to a more modern configuration I have just
noticed a new twist.

There is apparently no vent pipe on the primary!

The only possible safety feature I can see on the primary is a device
fitted to a Tee at the highest point in the primary circuit which I
can not identify. This is a vertical brass cylinder about 5cm high
and 4cm diameter with a screw-on brass lid with an offset plastic
knurled nut just under 1cm diameter with a screw head in the middle.
There's a single 15mm pipe entry at the bottom connected to the
primary circuit.

Can anyone help me identify this device? I'm rather hoping it's some
sort of pressure relief valve, but if not it seems that the system is
potentially dangerous in its current state.



I think I have now identified the device, and it's just an air
separator. See

http://www.rwc.co.uk/rwc/pricelist/heating.htm#air

and scroll down to "Automatic air vents".

http://www.rwc.co.uk/rwc/pricelist/i...g/Air_vent.gif

So am I correct in believing that this company installed a system
which is against recommendations and dangerous as used?

Keith Refson
--
Keith Refson 01865 435302 (Home)
23 Napier Road 07773 074233 (Mobile)
Oxford OX4 3HZ K.Refson AT Ntlworld.com