Removing TRV

The Medway Handyman was thinking very hard :

I think you will find that the roll pin is an Allen grub screw.

I did think that, but close inspection with a magnifying glass doesn't reveal a hexagon. Seems circular, which lead me to believe its a pin of some sort.

Is it an older Danfoss TRV?

on 22/11/2009, The Medway Handyman supposed :

I am CERTAIN that all of that particular make / model I have come across had an Allen grub screw. A roll pin just would not work to hold it in place. Try offering a small Allen key into the head.

The Medway Handyman wibbled on Sunday 22 November 2009 20:33

Being lateral, do any of the black bits want to rotate by hand? My last ones had a knurled black ring at the base that if rotated, locked and allowe dthe head to be lifted off. Didn't look exactly like yours though, so probably not helpful...

Thanks Harry - I shall try an allen key. Maybe previous attempts at removal have damaged the hexagon.

The split in a roll pin would visible on the end.

Clearly a job for the Angle Grinder :-)

BSF the old Danfoss-es used to have a cussed arrangement where you rotated a plastic collet-type-thingy against spring-loading whilst pulling away at the same time. Must say I don't recognise those Bar Stewards in your photos, Dave, but Sod's Law, I'll come up against them myself in the next week or so :-(

Even through the fuzziness of that pic the "pin" does appear to have a recess so probably is a grub screw .

I still have some of these at home, I think they were made by Thorn or at least some company beginning with 'T'.

Anyway they are definitely held on by grub screws, the older ones actually had a plastic collar/clamp around them held with an ordinary screw.

I was talking B@ll@x, they are indeed old Danfoss TRVs.

Thanks chaps. It will have an allen key inserted. "They don't like it up em".