Why is finding a new Thermo for my underfloor heating so hard?

[jwintermedia]

We have a sizeable house with full Polypipe? underfloor heating.
We have 16 thermostats (Belux WFHT-20221UK)

The main control panel (timer/on/off etc) is a Horstmann ChanelPlus 37xl

UFH was fitted when the house was built in 2004 (ish)

We have two problems
1) The spindles in the Belux thermos keep snapping and a company of 3D printers is helping me create new ones.
2) Two of my Belux Thermo's have stopped working completely. We are having a great deal of difficulty in replacing them as they are so old. My heating company (who didnt fit the UFH) have found two alternative thermos. One was fitted and blew the fuses and the second didnt works at all.
They have sent three heating electricians and they keep making reference to the wiring within the thermo. Something to do with there being more wies than usual???
I maybe a woman, but surely this cant be soooooo hard? Or is it?
Any ideas.

Picture of the inside of thermo can be found here https://www.dropbox.com/s/vvxxzyoangvxj5p/Thermo.jpg?dl=0

 

[oz-plumber]

Why don't you contact the company that makes the thermostats?

I found them and their wiring diagrams and other tech info.
They may be able to recommend someone who can sort your problems out.

In reply to the last line of your post - No, it's not that hard