You may know that difference between the cut-in and cut-out temperatures of a sensor is called its hysteresis.
With some 'smart' thermostats you can set those two temperatures seperately. I have heatmiser thermostats on our ufh system...
Tbh would just open the drain off on the boiler and wait for it to strop running etc towel over the pcb / back cover to catch any drips when removing the pump etc
Also, washing machine hoses could be an option because they are the same thread as my existing valves. I'll buy a 2 metre hose and attach to both valves and see what gets hot first as they'll only be on for a few seconds.
Other way round push fit on solvent weld
Push fit is a different material that’s capable of taking a higher temperature for a longer period without failure
I thought I'd update this thread on my heating system after 5 years of use. It's still working well and I've added more rads as I've finished rooms, I've got one small leak on the 3/4" valve feeding one of the manifold that I'm sure is...
Yep metric and imperial versions most likely if it’s old will be imperial and very brittle
Turn the water on slowly let it fill the pipe with hardly any pressure then once full finish off opening the stop tap