Poor IR results on electric UFH... options?

[HappyHippyDad]

Carried out an EICR and am now doing the remedials.

Poor IR results on conservatory ring which I have now identified as the electric UFH.

The UFH has 2 x line and 2 x neutral conductors on the load side of control panel (same terminal). I'm not sure why as the conservatory is only 4m x 3m so not sure why it needed two separate feeds.

Both cables of the UFH show faults. Side 1 N-E 0.24Mohms, side 2 N-E 0.75Mohms.

There is no earth conductor going to the mat/cable (whatever it is), just 2 x line and 2 x neutral plus the 2 core cable for the floor thermostat.

I have disconnected, but I was wondering if there is absolutely anything you can do to remedy this? I'm guessing moisture has got into the conservatory floor, and there is nothing you can do about it, but thought I'd ask.

Cheers all.

 

[Dartlec]

Carried out an EICR and am now doing the remedials.

Poor IR results on conservatory ring which I have now identified as the electric UFH.

The UFH has 2 x line and 2 x neutral conductors on the load side of control panel (same terminal). I'm not sure why as the conservatory is only 4m x 3m so not sure why it needed two separate feeds.

Both cables of the UFH show faults. Side 1 N-E 0.24Mohms, side 2 N-E 0.75Mohms.

There is no earth conductor going to the mat/cable (whatever it is), just 2 x line and 2 x neutral plus the 2 core cable for the floor thermostat.

I have disconnected, but I was wondering if there is absolutely anything you can do to remedy this? I'm guessing moisture has got into the conservatory floor, and there is nothing you can do about it, but thought I'd ask.

Cheers all.

There are companies that will repair them - but means getting the floor up of course.

Had a client who got one fixed a while back - separate company were called out by the manufacturer under warranty, and identified the fault to within one (large) tile somehow. Combination of thermostat and working out length from readings I guess. Then did some sort of repair with connectors wrapped with heatshrink - wasn't there so didn't see what they did. There's some pictures on my previous post.

They effected a repair, though then charged since they claimed it wasn't installed to manufacturer's instructions. Still working so far based on the last pic I was sent of the cats lounging on it!

 

[Pretty Mouth]

How was the L-N resistance, what it what you would expect?

Edit: By that, I mean continuity rather than IR

 

[James]

Has it been off for a longtime? If so it might need warming to dry the moisture out.

 

[Mike Johnson]

I thought UFH cable was waterproof? Two mats same room different readings?

 

[HappyHippyDad]

How was the L-N resistance, what it what you would expect?

Edit: By that, I mean continuity rather than IR

I can't actually remember, but I do remember thinking that it was fine.

Has it been off for a longtime? If so it might need warming to dry the moisture out.

No, it's been in daily use.

I thought UFH cable was waterproof? Two mats same room different readings?

Not sure, but I guess if it gets covered in tile adhesive it must be. as for your second question, that was my question too.

They plan to knock the conservatory down in around 3 years, so It's not worth the hassle and cost of getting a specialised company out, just wondered if i had perhaps missed anything simple.

 

[Mike Johnson]

The two mats are no necessarily the same size, so could have different readings, but curious if there is only one thermostat controlling both?

 

[loz2754]

Might not even be mats, they may have used heating cable, in 2 runs for convenience?
Either way, it should probably be disconnected if they're not wanting to have the floor up to have it fixed...

 

[timhoward]

The UFH has 2 x line and 2 x neutral conductors on the load side of control panel (same terminal). I'm not sure why as the conservatory is only 4m x 3m so not sure why it needed two separate feeds.

Both cables of the UFH show faults. Side 1 N-E 0.24Mohms, side 2 N-E 0.75Mohms.

There is no earth conductor going to the mat/cable (whatever it is), just 2 x line and 2 x neutral plus the 2 core cable for the floor thermostat.

As you are talking N-E, and the mat connections don't have earth, I'm assuming the low IR is on the supply side of the control box?
If so I wondered if is it possible to disconnect the two underfloor loop circuits and re-test, to prove whether the fault is control box side or not.
Sorry if I've completely misunderstood your post!

 

[FatAlan]

Does the UF heating actually work? Do you have manufacturers details as they should give an idea of the resistance for the element. Surely if you are IR testing the RFC that should be done with the UFH mat disconnected otherwise you will get a low IR. I’ll bow to those with more experience but my thoughts fwiw.

 

[Mike Johnson]

Would make no difference if they are mats or cable the total run of the heating element is what gives the resistance readings you check to ensure there is not damage prior to and after tiling, and yes should be taken disconnected from power, controls and thermostat.

 

[ipf]

The two mats are no necessarily the same size, so could have different readings, but curious if there is only one thermostat controlling both?

There will be if there's only one output point........or am I missing something?

....and what relationship have the conductors to earth if there is none? Once again, am I missing...............?

 

[Mike Johnson]

No I don't think you are missing anything, the problem is if the thermostat was supplied with one of the mats, cables or units, it could be its not suitable for the two together, the conductors to earth have no bearing at all to the condition of the mat, cables or whatever is under the screed, tiles or cement, the measurement normally taken for a UFH mat, cable or whatever, is to ensure it is still continuous, and has not been damaged during installation, the manufacturer even gives this resistance value on the product and advise's not to shorten, extend or join.

 

[Lucien Nunes]

Thread seems to be a bit drifty. As I understand from HHD's description, there are two cables / mats. Both have continuity, are functional and have been in regular use. When tested separately, both have been found to have sub-1MΩ IR to the mass of earth.

There is a way to stop leakage from joints in underground pipes without excavating, by pressure-grouting them with epoxy. I wonder whether a similar process could be invented for underground cables, by pumping in electricity coated with silicone or even just some plastic electrons followed by applying a potential to earth to attract them towards any cracks in the insulation.

 

[ipf]

Thread seems to be a bit drifty. As I understand from HHD's description, there are two cables / mats. Both have continuity, are functional and have been in regular use. When tested separately, both have been found to have sub-1MΩ IR to the mass of earth.

There is a way to stop leakage from joints in underground pipes without excavating, by pressure-grouting them with epoxy. I wonder whether a similar process could be invented for underground cables, by pumping in electricity coated with silicone or even just some plastic electrons followed by applying a potential to earth to attract them towards any cracks in the insulation.

And, to think, everyone was worried about creating a satisfactory vaccine for Covid.