Heated towel rail valves...

[rgf101]

I have a heated towel rail in my bathroom. There's no "normal"
valve, but there's an exposed screw on top. Bleed valve?

At the bottom there are two... don't know what they are. My assumption would be a drain valve, but they don't look like drain valves I've seen before. They don't turn. I'm reluctant to unscrew them just to see what happens....

Any ideas?

 

[Burnerman]

The bottom valves are Pegler Terrier lockshields and normally aren't adjusted...with the cap off they can be opened or closed with an adjustable spanner.
The one on the top is a bleed valve to let the air out.
John

 

[rgf101]

Cheers. Was looking for a draincock, I guess everything started to look like one...