Air being released from with a combi

[WaterTight]

Went to a custard who'd removed and replaced a rad and couldn't top up the pressure because filling loop wasn't working. Replaced loop and topped up but noticed air sound from top left corner of boiler inside cover. Steady woosh until pressure returned to zero then it stopped.

Told him I couldn't touch anything inside boiler as not gas safe and referred him on but out of interest what will have caused this because if he just took off a rad, bled it, lost pressure and couldn't re-pressurize then this sounds like something I'll come across again when I'm changing rads on combi systems.

Is it rare or should I be allowing for a visit from a gasman in my price on jobs where all I need to do is re-pressurise a combi after rad work?

 

[Leo21]

Sounds like an automatic air vent. And that's wat they do. Hissing stops when boiler is vented. Usually.

 

[jtsplumbing]

AAV inside boiler, some stick out the top others (new boilers ) tend to be on top of pump.

 

[WaterTight]

Right. Cos I've re-pressurised maybe 40 or 50 combi's and not come across this. So had I kept filling it it would have eventually stopped? And am I right in thinking that even if it is just an AAV I shouldn't touch due to not being gas safe?

 

[anz]

That's the Auto air vent, just removing the air that's found its way into the boiler.

If the boiler hasn't been serviced in a while, you could recommend to your customer to have someone look at it.

You could even pass on the details to your gas man, or quote for a service and get him to do it.

 

[anz]

Right. Cos I've re-pressurised maybe 40 or 50 combi's and not come across this. So had I kept filling it it would have eventually stopped? And am I right in thinking that even if it is just an AAV I shouldn't touch due to not being gas safe?

Yeah you shouldn't really be removing the cover.

If you carried on pressurising, it would have eventually stopped, unless its leaking.

 

[WaterTight]

I can't believe I've never had this before?

These are commonplace?

 

[Leo21]

Yep all the time, even more on modern ones.

 

[WaterTight]

Well I think I best give him his money back then since it would appear it's my stupid fault for not knowing this.

I charged cos I checked his rad valves and installed new filling loop (which he bought) but he shouldn't have to pay for a gasman to come by and turn on the filling loop for another 20 seconds because I was born without a brain.

Thanks all.

 

[WaterTight]

Ah-ha. All is good. Just phoned him and he hadn't yet phoned the gas guy's number I gave him. Told him to try topping up some more a job's a goodun. I'll keep my cashish 'n' all.