Boiler is highest point - qhat if air gets in it?

[diyAlex]

I'm going to fit some extra pipe work to our CH supply/return from the boiler. I'll be adding these to the vertical run from the skirting board area (where the current pipe work runs around) to the boiler. I.e. the vertical pipes that run up the wall to the boiler. This is a bungalow and the boiler is the highest point.

So when I've fitted these T's and new pipe, the air in them will travel upwards when I open the serice valves on the boiler (where the pipes go in to it).

So will I end up with a heat exchanger full of air?? And how to I get it out? Should I incorporate a vertical coming off the new pipes with a bleed valve in it or something??

Thanks!

 

[ratonnastick]

A lot of boilers will have a build in vent . Otherwise bring the pipes above the boiler, tee the pipes, put vent points above and gently slope the pipes across and down towards the boiler.

 

[diyAlex]

Cheers, I will dig out the boiler documentation and see if that helps (probably should've done this first

 

[diyAlex]

Well, it's a Vaillant TurboMAX Plus 828E, and on the front page for this range it says "Wall hung room sealed fan assisted combination boilers and system boilers".

So ... section 4.8.8 of Boiler Installation Sequence says

The boiler is fitted with an automatic air vent. Additional provision should be made to enable the heating system to be vented during filling and commissioning either by automatic air vents or manually

So I presume that means that the air vent fitted is not designed to let out a huge blob of air caused by new pipework!?

I've taken the covers off and I think I've identified the component (just wanted to see what it looked like). It's like a small plastic tub with a shraeder-type valve cap on top.

 

[bhm1712]

that sounds like the expansion vessel pneumatic fill point, and not the AAV.

should you be taking the boiler cover off?

 

[ChrisR]

You have to do nothing !

That air vent will let all the air out.

In operation, if there's a leak the pressure will drop and the boiler SHOULD stop before the hex is full of air.

If you like, start the boiler up with the gas turned off underneath it.
It'll "lock out" cos it won't fire, but the pump will have started and pushed water through the hex, air should hopefully get stuck in a radiator.

Leave the auto air vent cap LOOSE. (This is the one by the pump).
Leave the pressure relief valve well alone!

Practically every boiler in a flat, is configured like yours

 

[diyAlex]

that sounds like the expansion vessel pneumatic fill point, and not the AAV.

should you be taking the boiler cover off?

Nope, it's definitely the AAV - I've identified the component here: http://www.clickonbathrooms.co.uk/061707-vaillant-vuw-turbomax-plus-828e-automatic-air-vent.html

And yes, I should be taking the boiler cover off. I've got enough common sense and a stint in engineering to know what not to touch. And anytime the BG engineer has been around I've played very close attention to what you can take off and how it comes off. If you're never going to look under the hood of things that you own you're going to consign yourself to forever paying someone else to fix your stuff up.

Thanks for contributing, anyway

 

[diyAlex]

Thanks Chris, sounds like good advice.

I'll defo leave the PRV well alone!

 

[diyAlex]

Chris R - you were absolutely spot on Thanks

A friend and I have fitted the manifolds and sure enough the AAV let all the ait out and the boiler is good.