What are these - MH plumbing question?

[Glandwr]

Any ideas what these are connected with. Two pipes (red and white) terminating in 14mm?? in line taps and push fit stepped tube connectors. They are underneath a Truma Aquatherm boiler that feeds an Alde type underfloor heating system. I had assumed that they were to do with the boiler above them.

One, the white one, is weeping from the body of the tap and has been for some time. BUT the level in the header of the Alde type wet system doesn’t show the level falling. What else can they be.

I was paranoid about replacing the tap for fear of introducing air into the system (been there, done that). If its not to do with the Aquatherm system and simply the drain off for the domestic plumbing I’ll be very happy. What do you think is it common to have such drain off cocks? If they are just drain off cocks why don’t they have and elbow and exhast through the floor?

 

[Fisherman]

They look very much like drain valves.
The yellow parts are there to got a hose onto to drain the contents away from this area. I have similar drain valves with these hose fittings in my garage. I can attach a hose to them if I drain my system and drain the contents onto my driveway.