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Abbo · Joined: 02 Oct 2006 Posts: 25 Location: South Staffs

Hi,

Just in the process of doing my bathroom and I'm getting to the stage that I'm about to install the electric underfloor heating. My problem is trying to source 10mm flexible conduit, without having to buy a 30 or 50m roll!!?
The conduit is laid in the floor to give access to the floor probe should there be any problems with it in the future. All the spec says is that it has to be to EN 61386-1 (previuosly 50086-1). The question I've been trying to get an answer to is what alternatives are there to flexible conduit? e.g. could I used the oval pvc conduit or would this pose any safety issues with the heat etc?
Any suggestions?? I'm trying to avoid using 20 or 25mm conduit, because I don't want to have too great a step into the bathroom when the tiles have been laid. Wink

vince knight · Posted: Mon Sep 24, 2007 3:39 pm Post subject:

Which underfloor system and controller are you using?
Are you registered under part'P' of the building regs to be able to install the heating yourself legally:?:

Vince

Abbo · Joined: 02 Oct 2006 Posts: 25 Location: South Staffs

The system is the WarmUp sytem with the XStat controller. Yes I am Part P qualified.

vince knight · Posted: Mon Sep 24, 2007 8:37 pm Post subject:

The probe on the warmup system is designed to be installed directly under the tile in the adhesive. If you place it in tube then it will not sense the temp correctly.
I have installed in excess of 60 mats and loose wire systems and not ever had a probe problem.
Be sure to check the resistance of the mat before you tile though as they often are faulty out of the box.

Vince

Abbo · Joined: 02 Oct 2006 Posts: 25 Location: South Staffs

Cheers Vince,

The only reason I've contemplated the conduit, is because that's what the instructions recommend, should the probe decide to stop playing. My mate's done the same as you and just embedded his into the concrete. Even Danfoss now recommend putting the probe into conduit, but they recommend the 20mm conduit. I thought the same as yourself, surely in 20mm conduit, how can you get an accurate temperature reading when a little probe is rattling round in considerably bigger void than necessary??

Thanks for the advice on the resistance checks, I was going to do that anyway, but as it's the first one I've done, it's nice to get some advice from an expert.

AlanE · Posted: Tue Sep 25, 2007 7:35 am Post subject:

Just a thought(!!) but why not use 10mm copper tube?

Benefit of being able to to replace probe and better heat conduction than plastic.

Abbo · Joined: 02 Oct 2006 Posts: 25 Location: South Staffs

Someone had suggested that copper pipe could be an alternative, but then it was also a case of being metal would I encounter any other problems in the future with copper being a conductor? Plus, would you suggest that the exposed side of the tubing is bonded to earth as well as a safety measure?
Mind you I suppose once it embedded in the adhesive, it isn't like it's going to stray and come into contact with any of the heating wires??

vince knight · Posted: Tue Sep 25, 2007 12:01 pm Post subject:

The heating wire is surrounded with a sheath earth anyway so I can't see a problem Very Happy

Vince

Abbo · Joined: 02 Oct 2006 Posts: 25 Location: South Staffs

Hmm.

Being a plumber, 10mm copper piping might just be the answer!! I'll seal one end off and pop it into the adhesive and through the wall...job's a good un! Wink

Cheers for all of your advice. Where would we be without brill websites like this?? Very Happy