Baxi 80HE change AAV

[LegionOfBrad]

Hi there, I need to change the AAV on my Baxi 80HE as it got corroded and likely not venting any air. We have some air noise when the hot water is running (but not the CH) We had a bum Expansion vessel which has likely caused the leaking of the AAV

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• LegionOfBrad
• 10 Dec 2014
• 1

Can i just check the procedure is as follows.

Isolate the boiler from cold water supply with ball valve by it.

Drain down system from radiator on ground floor (Boiler is in the loft)

Unscrew and replace AAV and Oring. Make sure plastic screw on top of aav is lose so air can be vented.

Repressurise to 1bar.

Bleed Rads then set to 1 bar again

Does that sound correct?

Edit: I don't think i have to drain the rads. Just isolate return and flow central heating points then use a hose on the boiler drain point to just drain it down?

 

[ALCPlumbing]

If the boiler is in the loft is there not a drain point within the boiler or just below it. Will save a lot of time if you don't have to drain everything. Alternatively only drain from the radiator till boiler is empty. As you undo the AAV and it allows air in the boiler will start to drain any water that is left in it so don't just pull it straight out as you risk soaking the pcb. Isolate the power and tease the AAV out till there's no water left.

 

[LegionOfBrad]

Fitted this today. Had to bleed down a bit of pressure out of a downstairs radiator because the CH flow isolator wouldn't budge before hand. Other than that no problems at all. An easy enough job and it's now whispering nicely on the Hot Water rather than gurgling with air.

The used AAV valve was stiff as hell. Not surprised it wasn't venting correctly.