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  1. Vortigern
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    Vortigern Electrician's Arms

    Location:
    England
    Business Name:
    F.H. Electrical
    So...Got a call late last night client who I have done work before asked advice re builder doing electrics. Advised re CPS membership he checked on ESR builder not on there. Asked builder was he CPS member. Builder said seems best we part company client left in the lurch with no kitchen just bare walls building work half done. Client down 8 G.
    Agreed to do electrics on kitchen all good so far! UFH.. so he has UFH in bathroom adjacent to kitchen. And UFH under kitchen floor. Client suggested I put both heating mats on the one thermostat existing from the previous bathroom UFH. Bathroom is Klima/screwfix UFH and thermostat, new kitchen UFH is Heatmat. No evident thermostat cable coming up from floor. Clear so far? So for me its going to be a bit of a scramble sorting out three cables black and one cable white coming up from floor and sorting out thermostat(s) Any savants out there? This is a discontinued Tstat, and I have the file for it. I suppose the question is can you put an extra 12m² (Kitchen) onto existing 9m² (bathroom) existing thermostat. All answers will be treated in confidence of course.

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  2. PEG
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    PEG Trusted Advisor

    Location:
    Manchester
    Hi bud,if the two mats are separate areas,and there is a chance the thermostats are in,test out the mats and power up,then check the stats meter the temp rise.
    This may be one of them jobs, where you don't give the customer too much say :)
     
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  3. Gavin John Hyde
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    Gavin John Hyde Regular EF Member

    Location:
    Somerset
    Business Name:
    Sulis Electrical Services
    I hate underfloor heating as its great if installed properly. But every so often you come across a utter bodge job and the flooring above the heat mats is crap.causing damage. Breakibg up etc...
    I avoid it like the plague.
    As for your question have you tried the manufacturer as they normally have a boffin or two sitting around who might answer the questions.
     
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  4. Wilko
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    Wilko Electrician's Arms

    Location:
    Berkshire
    Business Name:
    Wilko Electrics
    Hi V - def not a savant on UFH so for what it's worth - with the mats in various watts /m2 and the stats switching capacity unknown, I agree with Peg - stick with existing arrangement and test - the mats may already be trashed as Gav reminds. Client had £ks vanished with last builder so might be best to keep the work in small chunks, in case the worst happens. Not very cheerful this morning, sorry.
     
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  5. Vortigern
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    Vortigern Electrician's Arms

    Location:
    England
    Business Name:
    F.H. Electrical
    Thats the next stop thought I would assay things from the forum first because everywhere else is closed.
    Yeh thats the thing, there is only one thermostat for the bathroom. The builder did not see fit to install one in the kitchen underfloor (sigh) so only the one thermo. I did say I can't put the both mats on the one thermostat.
    Sorry to hear that!
    When on site yesterday met with live sockets off walls and hanging in the middle of the room, this is a family home with kids, really bad case of builder electrics. At least the client caught on when the builder said he will do the electrics and got in touch with me. They have no kitchen so about to put in place triage/emergency installation the UFH can go hang for now lets get them a cooker etc.
     
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  6. Murdoch
    Online

    Murdoch Electrician's Arms

    Location:
    Woking
    Now is the time to redo it properly..... Not later when it's all fitted out and decorated...
     
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  7. Vortigern
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    Vortigern Electrician's Arms

    Location:
    England
    Business Name:
    F.H. Electrical
    Yes I have come to that conclusion. It means pulling up some tiles to fit a sensor, which has not been installed. But, not much choice on that one as far as the tech are concerned there has to be a sensor underfloor, which makes sense to me.
     
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  8. Murdoch
    Online

    Murdoch Electrician's Arms

    Location:
    Woking
    Good call.

    If you don't do this now any issues down the line will be your problem.
     
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  9. Vortigern
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    Vortigern Electrician's Arms

    Location:
    England
    Business Name:
    F.H. Electrical
    Those dread words... just thought, can't pull up the tiles it will damage the heat mat...:confused:
     
  10. Wilko
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    Wilko Electrician's Arms

    Location:
    Berkshire
    Business Name:
    Wilko Electrics
    Bolting Builder has not only taken money, but he's made off with a floor temp sensor? Now that is taking it one step too far ... I have heard folks put in 2nd sensor as a spare, such is the pain of replacing them after the event. Aghhh
     
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  11. PEG
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    PEG Trusted Advisor

    Location:
    Manchester
    Where there is a will,there's a way... if the MI states an underfloor thermostat is a requisite,it needs one,or leaving it a worker is not possible.

    The MI of most,require the thermostat to be placed in between the elements,and although the middle is usual,if the base/substrate is not thermally retentive,nearer the edge would suffice.

    In fact,if the "thermal mass" is solely the tile/adhesive,then any position which places the thermostat half the measurement from a heating element,of the distance between runs of element,will read the temperature rise.

    This may allow placement of the correct thermostat (if that can be determined) with judicious use of a diamond blade in a mini-grinder with depth-stop at tile thickness.

    All of the above is pretty radical intervention,and would necessitate the approval of your customer,and possible failure accepted and paid for...but the alternative is a bus ride from foot warming ;)
     
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  12. Vortigern
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    Vortigern Electrician's Arms

    Location:
    England
    Business Name:
    F.H. Electrical
    Good idea. Spoke with the tech. today (Klima) who said the room temperature aspect of their thermostat would be satisfactory without a floor sensor to my surprise. They suggested putting it close the the floor. Now that is what they said, but I am not convinced about that to be honest. I am the sort of person that could probably do a surgical intervention of that order, and await to see if the client can get any info from the builder as to what the hell he did exactly. It would seem he has cover the whole (4m x 3m) 12 sq m. with a mat, just really don't know at this stage so kitchen furniture will be going on top of the heat mat (not good) it is looking a bit grim for the client at the moment but I have not told them til I know better.
     
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  13. Wilko
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    Wilko Electrician's Arms

    Location:
    Berkshire
    Business Name:
    Wilko Electrics
    Picking up on the tech advice, Peg's suggestion and builders mat placement ... if the mat is under the cupboards, perhaps butcher surgically insert it under there? Out of sight, air circulation will be less and even if it's not in exactly the right place at least it's still got one.
     
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  14. sam400
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    sam400 Regular EF Member

    Location:
    sussex
    you can run 2 mats of of one thermostat/controller if the contacts are suitable rated, if not I have used a contactor in an adaptable box to run large areas off of one controller before.
    Also on some controllers have an option to look at room temperature for control rather than floor temperature.
     
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  15. anthonybragg
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    anthonybragg Electrician's Arms

    Location:
    NORTHAMPTON
    Business Name:
    CHARLTEC ELECTRICAL LTD
    I think they will have to bite the bullet take up a tile and install correctly with sensor this is how it is supposed to be installed for the heating to work effectively and efficiently. I am sure that there was spare tiles left /still available better to do it right than in the future get calls regarding it not working correctly.
     
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  16. ruston
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    ruston Trusted Advisor

    Location:
    Northumberland
    I would too, trouble is you will not know if it has just been lashed in and you may still get problems.
     
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  17. anthonybragg
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    anthonybragg Electrician's Arms

    Location:
    NORTHAMPTON
    Business Name:
    CHARLTEC ELECTRICAL LTD
    All you can do is hope it has been installed with care, test it and maybe if possible use a heat source camera to see where elements have been laid to reduce the chance of it being drilled through by other trades etc.
     
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  18. ruston
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    ruston Trusted Advisor

    Location:
    Northumberland
    Yes , the plan will not be there I bet. Are the utilities in , that would be a help.
     
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  19. Vortigern
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    Vortigern Electrician's Arms

    Location:
    England
    Business Name:
    F.H. Electrical
    @ruston@ruston there is no plan, the builder just disappeared like a ghost when asked if he was a member of a CPS. There are two supply cables coming from under the floor so maybe he put two mats in??? What size is difficult to say. The customer is not interested in regs and just wants it to switch on. I have told the customer I will not connect in any unconventional way, what they think they want to do with it is up to them I do not want to know. I have advised them of what is neccessary and will note the matter to cover my derriere in the cert
     
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  20. anthonybragg
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    anthonybragg Electrician's Arms

    Location:
    NORTHAMPTON
    Business Name:
    CHARLTEC ELECTRICAL LTD
    If the builder was carrying on the work in a correct manor , compliance with regs etc. could of included it in with building regs approval .The fact that he has bolted spells a bit iffy. What was the standard of electrical and building work like ?.
     
  21. Dave OCD
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    Dave OCD Electrician's Arms

    Location:
    Cornwall
    Business Name:
    Hendry Electrical Services
    He's already described that pretty clearly Anthony - I think atrocious is around the standard. In this situation as it's a bit desperate I'd test/verify the mat connections then consider using a programmable room stat, via a contactor for the load if necessary. With a bit of trial and error the customer could set a temperature equivalent to a nice warm floor temp.
     
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  22. Vortigern
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    Vortigern Electrician's Arms

    Location:
    England
    Business Name:
    F.H. Electrical
    From what I could see on initial inspection, electrics not good. Bare live wires hanging about the kitchen. Intention to put double range ovens (4.5kw) gas hob on ring (final) circuit along with dishwasher, tumble dryer and washing machine along with toaster kettle microwave electric grill etc. So not too good on the design side. I have run in a 20a circuit for the oven. He was going to get an electrician in (he told the client) but decided to "do it himself" The client baulked at this due to a catalogue of expensive errors. From what I have seen the builder would have been overreaching himself with the electrics.

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  23. Dave OCD
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    Dave OCD Electrician's Arms

    Location:
    Cornwall
    Business Name:
    Hendry Electrical Services
    It looks like it's just waiting to kill somebody, terrible ! I think this is more common than we realise but many unsuspecting customers who know no better trust builders to do electrics - I've had experience of a few [or the aftermath] who grab as many aspects of a job as possible, whether they know what they're doing or not doesn't seem to worry them.
     
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  24. Vortigern
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    Vortigern Electrician's Arms

    Location:
    England
    Business Name:
    F.H. Electrical
    Precisely my thoughts one of the first things to deal with safe iso. and so on. Indicative of someone who has no idea of regs and H&S etc. At least the customer had enough nous to check and stop work, he has a wife and kids to think about.
     
  25. mattg4321
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    mattg4321 Electrician's Arms

    Location:
    South East
    I've done hundreds of these now. That thermostat/controller looks like an old heatmat one from around 10 years ago. Having said that I suspect theirs was a rebranded version of something else at the time.

    Normally the thermostat/controller will run up to 16A of heating - you can obviously check this on yours.

    You can buy heat mat between 120-200watts per sq/m, however in this case you don't know what's been fitted. You can find out the current rating of a mat by using ohms law. Measure the resistance of the mat and divide voltage by resistance.

    The floor sensors normally read around 22kohms at around 20 degrees. They do vary though.
     
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