I have changed the mid position valve on my Ideal Classic System, having drained the system to below the level on the valve, changed valve, and then refilled and bled system. All rads getting hot fine upstairs and down but when its firing up first thing in the morning, there is about 5 seconds worth of air gurgling sound at pump/valve area. Also at the nearest rad to the pump there is still a tiny amount of air which ive been bleeding out on start up. Will this clear itself as this is only 12 hours after changing the valve or is there anything else I can try? There is a piece of verticle copper pipe with a square tap on the end by the top section next to the mid postiton valve. What is this for? Thanks in advance.
Advise on air in central heating system......
- Thread starter andymp
- Start date
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That upstand pipe is probablly an air vent.It does sound like you should give it a bit more time and continue bleeding when neccessary.Open that tap on the vertical pipe and vent there.Did you replace the inhibitor?
Ok. If I leave this vent open, will it draw air in? I didnt have to drain the system completely, probably around a quarter. If I have to put any inhibitor in, do I pour it into the filler tank and how much? The highest rad in the house is the only one that expells air when bled and even then its only a tiny amount. Would it be advisable to alter the ballcock slightly to let just a tiny amount of water in or shall I leave it for now and continue bleeding? Cheers.
The system will take a while to settle after being drained. If you open the air vent on the upstand you may find some air comes out, followed by water. Dont leave it open else it will flood the place!
There should be enough water in the small tank to cover the outlet by a few inches at all times, it will top up as necessary. Dont adjust ballcock unless needed. One bottle of inhibitor in small tank will be ample.
There should be enough water in the small tank to cover the outlet by a few inches at all times, it will top up as necessary. Dont adjust ballcock unless needed. One bottle of inhibitor in small tank will be ample.
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Thanks for all the info recieved. Hopefully it will settle itself over the next few days. Cheers! 
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