Re: [OT] Air in central heating

[Jim Noble <yahoo-groups@xxxxxxxxxxxxxxxxxx>]

Neil Spellings wrote:
> Craig wrote:
>
>> Check the 'automatic air vent' on the system, if this is stuck
>> closed it will not allow trapped air to get out of the system.
From memory
>> this was about 5 quid to replace.
>>
> Any idea what this looks like? I have an open system and also gets
lots
> of air in the upstairs rads.
>


I don't think vented systems have automatic vents, do they?

You're more likely to have an air separator and vent pipe - look for a
small cylinder somewhere near the induction side of the pump. Something
like this (monospaced font required!):

<-vent pipe to F&E tank.

pipe from  __
==========    <-cylinder
radiators
____=====  to pump


(The water enters the cylinder and swirls round the outside, allowing
the air to escape up the vent pipe.)

There will be another pipe from the bottom outlet of the F&E tank. It's
worth checking that heat works its way up this pipe as the central
heating system warms up. If the heat only reaches so far, and the pipe
is cold beyond that point, it's possible it may be blocked.

Jim