As a heating engineer when I talk about under-floor heating I’m talking about a wet-system of serpentine pipework laid within the floor not electric-mat heating typically found under tiled floors in bathrooms.
Three times in the past week I have been called out to attend to faults on under-floor heating systems and two things have become obvious to me. The first is that the installer only left the manufacturers instructions on site with no additional documents pertaining to that individual installation such as, how many loops in each room, which actuators are linked to the same thermostat , drawings showing the pipe layout and which rooms are controlled by which stats.
The second is the lack of instruction on how the system is to be used. Generally speaking under-floor heating is to be considered ‘constant heating’ i.e.; on all the time. It is not like a radiator system which is convection heat carried in the air. It is radiant heat and is reliant on the floor slab being heated over several hours with only minor adjustments to the comfort level via each room stat, with a night set-back temperature. Basically it’s on all through the heating season. Running it for a few hours in the morning then the evening won’t do any good at all.
There are many different systems out there so make sure you get and keep as much documentation as possible as the system is installed. It makes fault finding and obtaining spares easier years later.