worcester 28i bleeding/air lock/ HELP!

In the last few weeks my worcester junior 28i has been making some increasingley funny noises. It's a year old and the first radiator on the circuit has always needed bleeding regularly but recently bleeding it seems to lead to air getting in the boiler/pump!

Up until recently bleeding the radiator (which never seems to work properly as froth starts coming out for ages and I can rarely actually get water coming out) would not cure a gurgle as the heating kicked in in the following cycle. I can live with a gurgle. The other day however I did all the radiators and had to refill the circuit as the pressure dropped a bit too much and the next time the heating kicked on it sounded as though there was more air than water being moved around the circuit for the first minute!

So the next day I bleed the radiators again thinking that all the air will now be in the top of the upstairs rads perhaps having let some in by topping the circuit up?. Some air comes out - not a lot, but I'm happy enough pressuming problem solved. But It's still doing it particularly first thing in the morning when it's been off all night. It sounds terrible and can't be doing the boiler any good.

Am I missing a something - a bleed point on the boiler maybe, had a check of the instructions and nothing overly obvious and the plumber didn't mention anything. The boiler is the highest part of the system but I thought it was self bleeding??

Help me I don't want this to kill my boiler, please.

Colin

I don't want this to kill my boiler

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It sounds as if you've already half killed it. The pump may have been sucking air in for the last year, especially if the system pressure has been allowed to drop. This may have done quite a lot of damage, causing corrosion. The corrosion products may be depositing in the boiler too. You need a competent heating engineer to take a look at it and sort it out.

The pressure only dropped after I bleed all the radiators the other day and was imediately refilled. The boiler has otherwise been running perfectly.

The first radiator as I mentioned has always made a noise for a second as the boiler starts up but otherwise everything is nice and quite. It has only been making the extra noise for a couple of days - I didn't notice it this morning, but then I wouldn't have noticed WW3.

I was really wandering if there was an air vent in the boiler to bleed or that should be checked to make sure it's lose as it should be.....

I'll see if keeps up, and get a plumber in as necessary.

Thanks Colin

Auto air vent on top/back of pump. Any cap/plug should be loose.

the aav is inside the combustion chamber i think near the h/ex