Sorting out an airlock

[benjamin31]

Hello,

Fitted a couple of radiators on a microbore system today. It's a vented system, and the downstairs rads are all on drops.

I've filled it up, but when the boiler fires up there's a noise from it like a boiling kettle, some banging, then the boiler cuts out.

The flow pipe on top of the boiler is very hot, but the return is still cold, so I guess the boiler is cutting out because it's overheating.

I've bled the pump, and the airvent on the stab before the motorised valve, but this hasn't got rid of the air.

I've had this a couple of times, and the air's worked its way out by the next day.

Is there a way of getting rid of it other than just waiting?

Cheers.

 

[Newboy]

And bleed all the rads ?

 

[benjamin31]

that goes without saying!

 

[DCPlumbing]

You could try turning off the upstairs rads and set the pump on pump speed 3 for a few minutes. See if that'll shift it.

 

[superdupergasman]

switch off the boiler to prevent damage when trying to clear airlock.

You could try pulsing the pump on and off using the speed control inbetween speeds.

Everyone has different methods, I find speed 3 never works are its spinning to fast.

turn off HW and try it on CH only.

 

[benjamin31]

Is it possible to pulse the pump with the boiler off?

 

[superdupergasman]

should be, does the pump run with the boiler off??

if not then turn boiler stat all the way to min.

 

[The Baker]

that goes without saying!

Dont take this the wrong way but when the equasion includes "fault finding and a human being" the words "goes without saying" do not apply.

In my early years I was often amazed that something I had checked and thought OK were on fact not OK.

Those trying to fix things have to get their minds around the following;

The fault is still there its just that you have not found it.

Dont be disheartened, its taken me years as a self taught person to learn that.

Good luck sorting it.

Tim

 

[fazedup71]

you can also try running the boiler for a short while each time as the expansion from the heated water will help to push the air lock out of the system. I tend to sit by the boiler and turn the stat off as soon as i hear the kettling noise, leaving it to cool for a few minute and then try again after bleeding rads

 

[karlk]

one approach I have used is to put a hose pipe from the mains onto a low drain cock (vented system only) directing the flow by shutting off parts of the system that work ok and pushing the air out through the expansion/feed pipe........you need an assistant in the attic to prevent flooding!

 

[seco services]

make sure the overflows connected then you won't flood the loft.

 

[benjamin31]

Thanks for all the advice.

I tried running the pump with the boiler off............and what do you know, the pump doesn't run.

I took the pump off, and the impeller was clogged up, I gave it a little clean, replaced it and all was well.