Electric ufh not reaching desired temperature

[Jimmy2081]

Apologies in advance for the long post, hope someone can advise

We've had our floor tiled a couple of weeks ago. This week we put the underfloor heating on for the first time and gradually increased the temperature by 5 degrees per day

Today we've set it to 27 degrees and it has taken 6 hours to get to 20 degrees starting from cold at 10 degrees!

Currently it is showing as 20.5 degrees but have also noticed it goes to 21 but then drops rather than increasing to the 27 degrees I've set it to

Is this normal?

We have 2 mats but one temperature sensor, we've also noticed where the mat is laid on the concrete side it is not as warm as the side where its a timber floor with concrete cement boards

Furthermore on the timber floor side some areas of the floor are considerably warmer than other areas of the same floor!?

Any ideas what could be wrong? Could it be the thermostat/sensor or something else?

 

[Time's Ran Out]

Did you see the mats laid out or do you have a plan layout?
Was there any insulation laid?
10 degrees is too cold for a start up temperature - your sensor may not be in the correct position!

 

[Jimmy2081]

Did you see the mats laid out or do you have a plan layout?
Was there any insulation laid?
10 degrees is too cold for a start up temperature - your sensor may not be in the correct position!

The sensor was positioned in between the heating cables 300mm in

I saw the mat being laid down with the self adhesive mesh backing. In some instances the mesh was removed to avoid where the kitchen units and island will be placed

Would it be worth disconnecting the floor sensor from the thermostat to see if this makes a difference?

 

[Time's Ran Out]

Was the floor sensor in a tube in the floor so it could be replaced if it failed?
Sometimes if the sensor is not taped to the tube when it’s connected to the supply it can be pulled out of position.
What was the power output of the mats?
How large is the floor area?

 

[Jimmy2081]

Was the floor sensor in a tube in the floor so it could be replaced if it failed?
Sometimes if the sensor is not taped to the tube when it’s connected to the supply it can be pulled out of position.
What was the power output of the mats?
How large is the floor area?

Yep, it was placed into conduit and taped down

The mat on the timber floor side is 200w 6sqm and the concrete side it's 10sqm

 

[Time's Ran Out]

My floors only take 30 mins or so to warm up and warm up is the term. Some UFH are tile warmers and others can provide primary heat source. Mine is 150w and set at 24/25 degrees as it never really gets any higher. If you disconnect your sensor it will overheat, especially a 200w mat over timber ( even on cement boards).

 

[Jimmy2081]

My floors only take 30 mins or so to warm up and warm up is the term. Some UFH are tile warmers and others can provide primary heat source. Mine is 150w and set at 24/25 degrees as it never really gets any higher. If you disconnect your sensor it will overheat, especially a 200w mat over timber ( even on cement boards).

What I cant figure out in some areas its nice and warm as how I would expect it but in some areas of the floor its barely warm!?

 

[Time's Ran Out]

Can only be the way it was laid or lack of insulation. I have an area near a patio door without UFH mat and that’s where I head for when cramp sets in!

 

[Jimmy2081]

Can only be the way it was laid or lack of insulation. I have an area near a patio door without UFH mat and that’s where I head for when cramp sets in!

Its the timber floor as you walk in its nice and warm but the rest of the floor on the timber side which had concrete boards is not as warm!

The concrete side of the floor is worse!

 

[Time's Ran Out]

Without photos of the layout we’d just be guessing.