However, there are different models in the Diamant Plus series - not sure you can tell from the photo above, but does anyone know which TRV model would fit? Or any other recommendations? Failing that, I guess I could go for the Drayton TRV 4s...
Yep, understood. Ta.
Good to know that I don't have to faff about fitting new valves if I don't have to. Or paying for a professional to do it.
Am I right that the VT117 bodies can accept VT200 heads?
I'm also assuming those bodies in the photos are 15mm, but I'd need to check.
Read the earleir posts. They were TRV bodies sold with ON/OFF heads cheaper so the customer could add a thermostatic head later. You can use any TRV head on it with the standard thread. Look through the Honeywell heads and choose one.
Surprised to see the one direction arrow so check they're on the flow (seem to remember they were bi directional). If not you can undo it and turn it around or buy a complete valve - or by a bi-directional insert but that'd be more trouble than it's worth.