Help required to identify this water heater installation

[choco]

This photo was taken at at central London office block where there are two staff kitchen areas with identical plumbing layouts - and problems.
Both the hot sides of the monobloc kitchen taps are leaking above the worktop surface when the tap is turned on, and they drip when the heater is heating up.
I am trying to identify the water heaters so that I can replace the taps with the correct part numbers. The heaters are not labelled at all and the only clue is that the temperature dial says 'cool' rather than 'cold'.
Does the presence of a PRV mean that this definitely an unvented water heater installation?
If I can't find them then fitting an expansion cylinder and new bog standard monoblocs would be the answer.

 

[Ermintrude]

Stanton or ariston ? Data label ? Defo unvented

 

[Watters P&H]

It certainly looks like an unvented heater. if it is there should be an expansion vessel on the mains. this will need to be installed and either replace the cartridge on the tap or replace the whole tap. also the discharge is wrongly installed, it should be connected to a tundish and ran out of the building as a copper discharge. The plastic pipe its connected to wont be able to handle the high temperature if the prv goes

 

[gasmanrob]

I can't remember the make but I ripped a load out a few weeks back none of them were on drip taps though I replaced with ariston units inc expansion vessel on each unit 30 in total.

ill have a look in the skip when I get home as the plastics will still be there

 

[snowhead]

Look like Heatrae Sadia Hotflo 10 or 15ltr

Buy Unvented Water Heater Hotflo 10 Heatrae Sadia Online

 

[chris watkins]

As above, should be 15 Litre as they are sinks.
I thought it may be a vent tap as you stated dripping all the time when heating but from photo it does not look like they are.
No expansion vessel kit fitted.

 

[SimonG]

Cant see a check valve. But that could be my eyes

 

[snowhead]

Standard mixer taps permitted and check valve not required;

http://www.heatraesadia.com/docs/Hotflo_-_Issue_4_-_36005719.pdf

 

[SimonG]

Looking at the picture of the installation and the mi's there isnt the length of pipe for internal expansion so should have check valve and exp vessel. Well thats the way I read it.

 

[snowhead]

Looking at the picture of the installation and the mi's there isnt the length of pipe for internal expansion so should have check valve and exp vessel. Well thats the way I read it.

On the basis there is Zero pipe between the Cold supply into the heater and the junction with the branch to the cold tap, yes there should be Check and Expansion