Help! Question for plumbers (or partners of)

[Osteria]

Plumber is coming in the morning so need to know…
I have a Vaillant boiler and it kept getting F22 error (pressure)

Boiler man comes from a reputed company and says I need a new PRV, it’ll be £150+VAT. Ok I agree.
the day they are meant to fit they call asking to send a pic of the model of boiler as they think it’s the wrong PRV… it is. They say they’ll come back in new year.

I call up to get it booked in and the man who owns the company says “you may also need an expansion valve” I said that I was told a PRV only. He said its up to me but he’d advise it and that’s £350+ VAT.

Now, I don’t know if I’m being taken for a ride. I was told I only need a PRV. Now someone who hasn’t ever seen my boiler suggests extra. I don’t know what any of these things are and if I’m being taken advantage of or if he’s right.

can anyone help?

Did he definitely say valve? It wasn’t an expansion vessel he was referring to?

A PRV (pressure release valve) only costs £20-£50 so I hope the £150+VAT is including the work!
I'm guessing you have a drip through the tundish? If so it could be a PRV or the expansion vessel, but the person who came out should have been able to tell if the fault was in the expansion vessel

I'm not a plumber but I've had a lot of issues lately so have learned what each part of my hot water cylinder does, as each part was replaced

Boiler man is here and he’s said the expansion vessel is broken. He said the bag inside has split.

he showed me this by taking out the vessel and it has water coming out of it. He said that shouldn’t happen as it’s in a bag.

obviously I don’t know if this is right