Valve Closed on Boiler

[thunder001]

I was working on my boiler last night an emerald series model EM-100 and noticed after replacing the expansion tank that one of the valves in the front of the boiler was in the closed position. I never closed that valve so I'm figuring it should be. Could someone tell me if that valve should be closed? I just want to make sure since I'm not sure if it needs to be. I've researched the internet with no luck.

Thanks in advance for everyone's help.

thunder001

 

[Jm66208]

Back up some and take another pic. It might just be a bypass. Cant really tell from the pic though.

 

[Sponsor]

 

[Jadnashua]

It may be part of a primary/secondary loop configuration, and it's disabled. Can't tell without seeing more of it.

 

[JohnjH2o1]

It looks like it's the cold water line to the tempering. It could be that the tempering valve has failed.