Boiler noise/pressure loss

[Charlotte]

I found this forum on google as I need advice. Before I start, I know nothing about plumbing or central heating systems other than what I’ve read online. I’ll explain, basically we rent, sane place for 8 years and for quite a number of those years we’ve had to top up the boiler pressure way more often than normal, sometimes in the summer every three months or so, if the heating is on in winter a lot more and the last few days every 48 hours. We told the letting agent but the contractors they use are useless and they just asked if we had damp patches anywhere and then left after fiddling with the boiler and checking a few radiators (one did have a leak but was sorted and pressure loss still occurs). On top of this, the boiler makes this awful noise when heating is on (video below) which I can stop by turning on the hot tap. My extremely limited knowledge tells me this may be the pump? Engineer just kept saying “we’ll I can’t replicate the fault so there’s nothing I can do” and shrugging when I showed him the video. One radiator in the living room is also now hot at top but cold at bottom though I’ve only just noticed this.
My questions are, I’m presuming this boiler noise isn’t normal?
What could it be?
Could it in anyway be related to pressure loss?
If not then do we have a hidden leak? I’m dreading that as I’ve heard it involves ripping up floorboards too to find it!
I’m only asking so I can have sone kind of info when dealing with the letting agent and contractors instead of just being constantly fobbed off. Thanks for your help.

11 December 2022

m.youtube.com

 

[gmartine]

It could be a faulty PRV (Pressure Reducing Valve) and or faulty expansion vessel. Locate the small copper pipe that is often turned in on itself on the outside of the boiler wall (usually), see if it's leaking or has leaked that would be an indication of the above faults.

 

[Deleted member 120897]

It could be a faulty PRV (Pressure Reducing Valve)

Pressure Relief Valve.

 

[Deleted member 120897]

Charlotte - the noise sounds more like the Diverter valve, not the pump. The noise isn’t normal, but won’t do much if any harm either. As per @gmartine check the safety discharge pipe from the prv, as it could be passing, and also check what the pressure is doing when the heating is on.