2-Port Valve wrong way round?

[ma9mwah]

Hi,

 

I've just moved into a house that has a UVC system installed (with gas boiler). Sometimes when the hot water timer switches off you get a loud bang/pipe rattle.

Looking at the piping in the airing cupboard I think the 2 port valve for the hot water coil might be installed the wrong way round (but then again there's some piping I don't quite understand).

 

I've attached a picture and tried to annotate it to make it a bit clearer. 

 

I thought the piping was:

Green feed from boiler,

Yellow and light blue was the S-plan 2 x 2port valves

Red return to boiler 

 

Should valve A be the other way round?

Should valve 2 be open or closed, and what is the Orange pipe for? 

[Nickfromwales]

“A” connection is the UVC > boiler return, not flow, so the valve is the right way around just it’s normally on the flow, so in the wrong place afaic. 
Looks like it’s not plumbed in correctly but I just cannot tell without better pics / taken from other angles. Can you upload more plz?

[ma9mwah]

12 minutes ago, Nickfromwales said:

“A” connection is the UVC > boiler return, not flow, so the valve is the right way around just it’s normally on the flow, so in the wrong place afaic. 
Looks like it’s not plumbed in correctly but I just cannot tell without better pics / taken from other angles. Can you upload more plz?

Hi Nick,

 

Hopefully these will help you out. The UVC is labelled Flow at the bottom, Return in the middle.

[Nickfromwales]

Ok! That’s a first for me, as all that I’ve installed have been the other way around. 
So yes, a simple fix and deffo the cause of the water hammer noise you’re getting. 

A quick drain down, spin the valve round, fill back up and then to the pub to celebrate. ?