Installing UFH

[eskimo39]

After numerous problems installing Under Floor Heating I am trying to decide if spending a couple of hundred quid on some testing gear can help eliminate faulty mats/probes etc.

Numerous times I have been called out because the probe has failed on an install (customer usually supplied equipment) and 9 times out of 10 it has been faulty from installation. I spoke to a few companies who say a 5m2 mat will have a resistance of say 102ohms but the probe would be 1200kohms at 25 degrees celcius and unfortunately my 1652 does not register that, plus how can I tell if it is at 25 degrees???

I am thinking of buying a Fluke 62 infra red thermometer and a low ohm resistance meter. The plan is then to buzz out the mat first to check it's resistance & continuity, if that is fine, let the tilers/myself etc install mat. Then temporarily energize the mat before it is covered with self level compound. Then using the fluke 62 keep a check on the floor until it reaches 25 degrees before testing the probe at this temperature with the low ohm resistance meter.

After it is tiled I can also check the temperature with the fluke 62 to clarify that it corresponds with the stat.

Does this sound too over the top and am I just looking for excuses to buy new tools or does anyone else on here do something similar?????

 

[Addlight]

I'd have thought it would be difficult to control the room evenly to get mat to 25C after it is laid out. Couldn't you test it while still rolled - put it in small room , adjust rad to get temp to 25C and let it 'acclimatise' for a few hours, then test? You can then check temp with cheap digital probe thermometer.

Also, doesn't 1652 MFT already give you the low ohm reading? That's down to 0.01 Ohms, so it must do that anyway.

BTW, you never, ever need an excuse to buy new gear!

 

[andyb]

You seem to be thinking about this too deeply.

I've fitted dozens of these and never had a problem with installation.

Every new mat should come with a label stating the resistance of the element, this needs to be checked when you take it out of the box, then after you have laid it, (or you need to attend site if laid by someone else) you then have to re check this after the floor has been laid.

If you are having a problem with the sensor it's more than likely being installed too close or touching the element.

You have all you need with your Megger 1652.