Unvented system and expansion tank pressurisation

[depr11259]

I've recently had a prv changed by a British Gas engineer under the homecare contract that I've taken out. The valve had failed and water was pouring out from the overflow pipe.
The valve was replaced without too much issue. However, the red expansion tank above the boiler was NOT re-pressurised after fitting the new valve. The engineer told me that the system would re-pressurise itself when I used the system over the next few days. I've been told by a plumber friend that this is an error and the tank should have been re-pressurised after the prv was changed.
I'd really appreciate some guidance from an expert in this forum in terms of which advice is correct.

 

[ShaunCorbs]

Is it on the cylinder the valve or below the red expansion tank ?

 

[depr11259]

Is it on the cylinder the valve or below the red expansion tank ?

The drip (water flow full force) was after the prv that had failed and the drip has now stopped. Following the replacement of the prv, the engineer did NOT re-pressurise the red expansion tank. Is that a mistake, should it have been re-pressurised?

 

[ShaunCorbs]

Yes he should of or replaced it

 

[depr11259]

Yes he should of or replaced it

Thank you

 

[Scott_D]

Are you sure it’s part of the unvented cylinder?
Red is usually for heating

 

[SimonG]

Got a picture of it all?

 

[Ben-gee]

When you say prv do you mean pressure reducing valve or do you mean pressure relief valve?

 

[depr11259]

Thanks to Scott_d for making me check the colour of the expansion tank. I wrote the message while away from home and from memory. I called the other half to check and the expansion tank is white!
It's located above the hot water cylinder. I don't have a picture of the area at hand. I'll be back home at the weekend and can post a pic then.
In the interim, thank you for all of the replies and assistance so far.
Paul

 

[moonlight]

He still should have checked the vessel, re-pressurised or exchange if necessary.

 

[John.g]

Which PRV failed?, the T&P on the unvented cylinder or the PRV on the heating system?

 

[SimonG]

That's why I wanted a photo. I would be surprised if the pressure on the vessel wasnt checked whilst the pressure was off. Well that's what I would do.

 

[depr11259]

It was a BG engineer (Homecare) who called at 4pm on a Friday and he was very eager to get the job done quickly to start the weekend (It was the euros footie weekend). Perhaps that's why the pressure wasn't checked??

 

[depr11259]

As promised, here's a picture of the installation.
Paul

 

[John.g]

This is the correct way AFAIK, I have seen these in a few places on the continent with NO expansion vessel, the expansion valve releases the expansion volume each time the cylinder heats up, don't know if this met local regulations or not even though a expansion vessel should not be considered a safety feature as it can fail at any time and fill with water.