Bm2 Problems after pcb replaced - loud banging and gurgling noises in system

Hi
I hope you can help me?
Out drive pump pcb failed and the system tripped. We replaced the board, started the system back up and since have had loud banging and gurgling in the system? The gurgling suggests air in the system? We have turned all the taps on to see if that would solve it but doesn't. We have bled the radiators too.  The banging and gurgling noises are very loud and I am very worried! There was a screw on top of the pump that when undone some air came out of but when water came out we did it back up again.
I think I have gone as far as I can go with my limited knowledge after reading a lot of feeds I can't tell what to try next?
We have hot water and the radiators are hot so assume the pumps are ok - they are both hot. The header tank also has water in it.
Not wishing to sound helpless but am a female with no clue about ch systems ? What else can i do? Do I need to call an engineer? Please help?

First of all read the posts on the BM II.
Mike

I thought I had? Can u give me a clue as to what I've missed?

1; Check the unit will take water.
2; Check and bleed both pumps and air bleed above pump near unit.
Check you have fitted correct board.
Check you have wired it correctly.

You have posted in this topic.
Boilermate 2 Not filling

Boilermate 2 banging

Gurgling noise after a new Radiator was fitted

Banging crashing and gurgling!

gurgling noise

Look through the BM II posts
The titles I have given you.
There are more
Mike

On all those Gledhill Products are a foe things you can do yourself with a minimum on tools, but also a lot you can't do without staying on front of the system and get all things checked over with some professional gear. If anything could be fixed via e mail and some reading, there would be no need for this forum or any of the Gledhill specialised engineers out there. We only can help up to a DIY level , above this you will need a visit from a Gledhill specialist. There could be a lot of faults ( blocked inlet on the F&E Tank, trapped air regards to dodgy layout of pipe work, partly blocked radiator valves ....)If you cannot get the problem on your Boiler fixed with some simple information from this Forum, you have to call a specialist in, who can analyse the system in person, not just via some e mails or phone calls.
Sorry
Kind regards Mario at Mario's Boiler Service
( PS to Mike: hope you have found a supplier for the XB442)

Thank you for all your suggestions. We have got a lot of air out of the valve by the pumps - it's taken over 2 hours. It's banged and gurgled again since so not sure this disaster has ended just yet!