Vaillant Boiler making noise/ Expansion Vesssal ???

Hi

i have a Vaillant Boiler the first problem was the escape valve was leaking this was replaced and now no water leaking outside.

From this a 2nd problem boiler is making noise. The heat exchanger has been cleaned and flushed out to clear debris and replaced. Boiler working fine however the last time this one done we had a problem with the pressure rising..... and then shutting down..

We was told the expansion vessal needs charging. i have located where this is but Iam not sure if it needs charging how do i check?????

i know u can use a footpump it says 10 psi on the it.... Does the boiler need to have no pressure in it when i pump air in ??

Please help

Many Thanks

isolate and drain the boiler

pressure should be around the 1 bar mark

the valve is on the top of the vessel (usually)

If your EV needs charging it'll be full of water - several litres. When you pump up the EV (to about 15psi) you'll need to leave the drain point open (the ones under the boiler are fine, don't use the pressure relief pipe though) to let those several litres out.
If water comes out of the air pumping point, your EV is bust and you'll have to do more...