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Discuss Electric ufh not reaching desired temperature in the Tiling over Electric Underfloor Heating area at TilersForums.com

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So we isolated the mat which is on the timber floor side, disconnected the sensor which only left the mat in the concrete floor side connected for approx 6 hours.

6 hours later the floor is barely warm! you can just about feel some warmth on the tiles :(

Should i leave it on longer? If so is there any risk of damage, overheating etc given that the floor sensor has been disconnected

The thermostat doesn't have an air sensor
I forgot to mention that the advice I have given is just an exercise purely to confirm that the system functions and will get to a temperature.
Because the sensor has been disconnected there is no over temp protection so don't leave the system running constantly unmonitored otherwise there is a risk of cooking the underfloor system.
 
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I forgot to mention that the advice I have given is just an exercise purely to confirm that the system functions and will get to a temperature.
Because the sensor has been disconnected there is no over temp protection so don't leave the system running constantly unmonitored otherwise there is a risk of cooking the underfloor system.
Yep agree, hopefully the heat comes through and will make sure i switch it off before going to bed!
 
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Cheers I'll do the above and report back

The floor setup is as follows

On the timber floor side it was overlaid with 6mm cement boards, primed and the mat laid on top followed by the adhesive and tiles

The floor sensor was positioned 300mm in between the heating cables on the timber floor side

The concrete side no insulation was laid as this would have increased the height of the floor. the floor was levelled using levelling compound which also encased the underfloor heating mat, followed by the adhesive and tiles.

The mat is 2mm thin 200w per sqm cable mat
Okay. So on the concrete side you have no insulation which means your heat losses will be very high and so warm up times will be much longer as you are heating a concrete slab instead of reflecting the heat upwards and out through the floor. It's a shame this wasn't considered as even a 6/8mm sheet of insulation would have made a big difference here so your losses would have been far less and you would have felt the benefits far quicker. This will also have an impact on your energy bill too!

Obviously, the timber floor side will heat far quicker than the concrete side, something that the installer should have known and so should have set the sensor within the concrete side and not the timber side as what happens is, the timber floor is coming up to the required temperature far quicker than the concrete side and as the sensor reads the set temperature required within the warmer floor, it then shuts off the system until it cools again. This means that the concrete side will never reach the same temperature as the timber floor because the warmer of the 2 floors is being sensed and not the cooler of the 2 floors. Had the sensor been placed within the cooler concrete floor then this would be the monitored floor, allowing it time to reach its temperature before tripping when it has reached its set temperature (hopefully that makes sense) giving you a warm concrete floor.. It should be noted though that you may not be able to set the controller at maximum for risk of overheating the timber floor side which will get hot far quicker than the concrete side and get hotter too.

There are a few options here now.

1/ increase the temperature setting on the controller to maximum, with the sensor reconnected where it is and see if this helps give time for the concrete floor side to get to a warmer temperature (it will never be the same or as warm as the timber floor side), but there is a chance that this may not come up to a nice warm temperature at all before the timber floor sensor reaches its max set temperature and shuts off, just as it does now.

2/ relocate or fit a new sensor within the concrete floor and sense this side and not the timber floor which will allow it time to come up to the set temperature. Obviously you may not be able to set the controller temp to maximum as there could be a risk of overheating the mat on the timber floor side, but you could carry out a monitored test on this to see just how hot it may get being set at maximum, just for piece of mind.

3/ fit an air sensed controller however, you may still feel a big difference in floor temperature between the timber and concrete floors. With this option though the location of the controller would need to be considered carefully and for sure needs to be in the same room as the underfloor system. Things to consider for instance is the height it is mounted from floor, it is mounted over the timber floor side of the room which may get warmer quicker, is it in a sunny spot near a window where the suns heat may affect it, will it be affected by heat from the kitchen when cooking etc.

4/ (This is drastic) run 2 independent systems, one on the timber floor side and one on the concrete floor side which in this scenario you would have 2 floors with similar temperatures as they are monitored and controlled separately. This in my opinion should have been the recommended option to you.
 
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