Under floor heating

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Monkeyboy

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I need some help boys. I've been to a job to repair under floor heating. It's never worked properly due to it being installed wrong.

It has 3x 8m mats @ 200w per metre 1.6kw = 6.9A each mat

Total = 20.7A

All 3x mats and floor stat are connected to a 13A Max time controller and has damaged the controller

Can i fit a contactor or relay somehow to fix this problem?

If so how do i do it?

Under floor heating is not my strong point!

Cheers boys

Mark

 
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That would do the job. Replace the damaged controller which would then feed the coil of the contactor only, then a 30a supply to one side the contacts and your cold tails on the other. A 3 pole contactor could have a mat switched across each pole.

Deke

 

seajayess

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The only problem you will have is the lack of cables at the stat, you will have to install a contactor somewhere like in a cuboard and then switch the contactor from the room stat and the mats via the contactor, realy should have been wired on first fix, if you can get the cables in its easy to do CJS

 

Mr Smith

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i have read on another thread that some under floor heating controls do not interface well with contacters and relays .

may be worth checking out .

mr smith .

 

Monkeyboy

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The only problem you will have is the lack of cables at the stat, you will have to install a contactor somewhere like in a cuboard and then switch the contactor from the room stat and the mats via the contactor, realy should have been wired on first fix, if you can get the cables in its easy to do CJS
What i have on the job is...... Behind the room stat 3xpair for mats 1xpair for floor stat and 2.5mm L&N supply

What ever needs to be done to

get it right needs to be done!

Any suggestions?

Mark

 

seajayess

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Do the 3xpair go th the CU the L/N to the CU room stat to the CU

You will need to feed possibly three contactors from the CU then connect the three mats to the contactors and use the stat to energise the contactor. If all the cables at the stat go back to the CU you have enough cables to do it. If not the L/N possibly go back to the CU and may be the roomstat goes back to somewhere near the CU if so put the L/N on a 20 Amp breaker through a contactor use the roomstat cable to feed and return switch line back like a loop plate to a contactor I know the load is just over 20 Amps but it would be worth a try as the supply will proberbly be more than 230 and this would lower your Amps are you sure the mats are 200 watts per meter as devi mats are only 100 watts per meter CJS

 

DonkeyDong

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by the sounds of the cables you have, you have a problem unless you can locate the contactor at the room stat location - otherwise you need to change the cabling.

If there is room to fit a contactor there, then its an easy job. Either get a single pole contactor that is capable of the total current, or get a three pole one capable me switching each mat.

If its a single pole one, then connect the power to the room stat, connect the line/power to the switched common of the contactor. Connect all the mats to the switched l1 on the contactor. Common all the neutrals to the supply neutral. depending on the room stat you may need to power the switched output - if so bridge it from the line terminal. Does the room stat have dedicated terminals for the floor stat - are they seperate stats? If not dedicated terminals, connect the floor stat between the switched output of the room stat and the l1 of the contactor coil. Then l2 of the coil back to the commoned neutrals.

Simple :)

D.

 
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