Advice on under floor heating

[mikel]

help please,

Been asked by a plumber to help him regarding a bathroom extension he is fitting out. The customer wants under floor heating (will be tiled over the top). The floor area is 45 m2, of which 37m2 will have the under floor heating. Now I've only done 1 underfloor heating project before but it was a small, simple one mat job. This one is going to take 3 mats and the total rating is a little over 6000w. The plumber is thinking of putting 2 thermostats in as the max current (of the ones customer wants) one can take is shown as 3400w.

I was thinking of putting a radial circuit in (4mm) to provide the power. Is there a way I can get round needing 2 thermostats to cope with the power demand.

 

[springcrocus]

You could use a single thermostat to switch a contactor unit.

 

[mikel]

After I made the initial post I thought of that. Are there any restrictions on how far from the thermostat I could place the contactor

 

[Evans Electric]

No restriction at all on the contactor, is there a cupboard nearby or even high up the wall against the ceiling perhaps or the loo next to bathroom. Avoid the loft if it were me as if it goes wrong or you need to do some testing , you don't want to keep climbing up there, unless you don't mind loft lagging ,I hate the stuff.

Deke

 

[seajayess]

yes connect them through a contactor or three contactors and three radial circuits as load will be about 27 Amps and tell the client to start saving money to pay the elecricity bill CJS

 

[Apache]

26p per KWh

6000W for 1 hour of heating

=

 

[mikel]

If the new bathroom is 45m2 floor area then I don't think they'll be concerned about the running costs do you. :^O

 

[seajayess]

Dunno Mikel the credit crunch can strike even the wealthiest of people CJS

 

[Apache]

If the new bathroom is 45m2 floor area then I don't think they'll be concerned about the running costs do you. :^O

ooh if its that big why not wack a couple of sockets in

 

[kme]

You`ve got mail, mikel.

r.e. distance between contactor & T-stat. Try not to space them too far apart - extra capacitance of the cable will enhance the EMI issues I mentioned in the PM.

HTH

KME

 

[mikel]

Thanks for the mail kme, makes sense what you say. Boy am I glad for the advice of this forum. Guiness DrinkGuiness Drink for kme

 

[kme]

Ta very much. They went down without touching the sides!!!!!