No hot water - boiler not firing - cylinder temp 27 degrees

[Gray0689]

No the stat not being cut in to insulation won't be the problem just fitted by a muppet so if they can't get that not right god nows what the problem could be
Sounds more a control problem than a plumbing problem
But impossible to be certain without seeing it IMHO

 

[mountainman]

Exactly Gray, 26 posts and no closer to resolution.
Time to get a pro in.