Valliant banging noise and pressure issues

[Harleybear]

Had the leaks in my boiler repaired yesterday, all was fine yesterday and now today the pressure keeps dropping to nothing once I put heating on or hot water. When I put on the hot tap there's a banging noise on the boiler and the pressure keeps jumping up and down a few times then goes to zero.

Why is this? Can't get anyone out until Thursday now!

 

[Stuckinarut]

Sorry, only just seeing this. Sounds like expansion issue with PRV activating

 

[Harleybear]

I had to have a brand new boiler fitted