how to fix f22 problem on boiler?

Yes, YOU can help.

Have a look in the manual.

Not got one?

Work out the make and model of your boiler - let's call them Make and Model, shall we?

Do a Google search for - say - "Make Model Manual". You could even just go straight to the makers site and see if you can find it there.

Does the manual help? Maybe.

If you still need help you could try another Google search for - say - "Make Model F22"

If you still need help, you could try to find a dedictaed plumbers forum

Anon
January 2017

You do not say the make or model of your boiler
You do not say the pressure
You claim it's not a combination boiler

So this video is no help...
https://www.youtube.com/watch?v=iApHxkj4cOA

Good Luck...
January 2017