Electric in-floor heating
10/17/2017 at 11:01:03 AM
Some years ago, we had a contractor do some bathroom renovations for us. The quality of the work was outstanding, but we're finding out that there was one hiccup... we're not getting heat from our In-floor heating. An Instrumentation Tech tells us that all signs point to the heating mats being installed in a series, rather than in parallel.
I don't want to make this about going after our contractor. The rest of the work he did was great. So my question is, can anything be done electrically to get our floor heated again, without tearing-up the floor? The Tech is wondering doing whether more power can be sent to the mats. The thermostat is rated at 120V or 240V. The problem as I see it is that the circuit breaker for the floor also controls other lights and outlets.
Any workable ideas are appreciated. Thanks.
10/17/2017 at 8:09:44 PM
The connection for the mats or the individual cables will be in the junction box where the t-stat is. So if there was a wrong connection, it should be able to be fixed there. If there is a connection in the floor , the product was not installed properly and likely will not work.
Cheers
John Kuehnl-Cadwell
Master Electrician
Datawise Solutions Inc
10/17/2017 at 9:17:21 PM
Thanks for the response. I think the Instrument Tech was saying just that - the mats weren't installed correctly. He said the readings suggest that the mats were connected to each other, rather than each one independently to power. He was wondering - since the 2 mats are "halving" the power being supplied - if by increasing power to the mats the in-floor heating would then work properly. That may not have been clear in my original post.
10/19/2017 at 3:33:13 PM
You could "do the math" to see what the total number of watts is based the resistance and determine what voltage you would need to get it going.
You may find that applying 220 volts will not solve the problem because the resistance is too high.
Do a search for Ohm's Law and it will give you the basic formula you need. Also the assumption would be that the heating cable is rated for 220 volts. I assume the circuit for the heat is large enough to handle the increased load from a series connected mat.
Additionally, if you are going to put this on 220 Volts, you will need to run a dedicated circuit as you stated it is connected with the lights and receptacles...
Cheers
John Kuehnl-Cadwell
Master Electrician
Datawise Solutions Inc
10/19/2017 at 3:56:07 PM
That's helpful John. Thanks.
10/22/2017 at 9:28:06 PM
if the power for the mats is being controlled by the same circuit as the lights, than you cannot simply wire it for 240 volts as it will affect the whole circuit. Are there not any labels on the in-floor heating wires to get you the cabling info? These labels should be in the thermostat junction box. Some people who have no clue of how to install these simply cut the end of the wires rendering it an open circuit in the floor, or splicing in the floor changing the resistance and causing a serious fire hazard. Call the manufacturer and seek help from them, not from a instrumentation tech. If you do not know who makes it or if there is no temperature sensor in the floor, do NOT use the heating. Do an internet search for the man in Niagara who died and had 3rd degree burns from his in-floor heating wired wrong... sad but true.
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