Control a 220v baseboard heating system with arduino

Hello

I am in need of some guidance.

I would like to control my 220V baseboard heating system from an Arduino. I have done some searching online for Relays that I could use to switch on and off the system. The information I have seen is confusing. So far it seems like I should use this: http://yourduino.com/sunshop2/index.php?l=product_detail&p=358.

I am worried about the load. In my living room I have 1 6-foot baseboard, 1 5-foot, and a 3-foot connected to a thermostat I bought at Lowes. I think with the three devices on this line they tend to get a little warm. That makes the thermostat think the room is warmer then it really is and turns off the units.

I want to put a temperature sensor on the Arduino and based on the room temperature turn the relays on or off.

Does anyone know if the device I put the link to can handle this? If not can someone recommend one?

Thank you all for your help
Ed

The device that you asked about is not suitable.

It is rated only for 2 Amperes per relay. You need to know what the power rating of your heaters is. Typical ratings that I have seen is from 500 to 2000 watts. The equation for power is power = voltage X current. So for example if your heaters total 2000 Watts then you need a relay that is at least 2000/220 or 9.1 Amperes. You should over rate the relay by at least 20%, I believe so a 12 Ampere relay would be better. Also from a mechanical consideration I wouldn't build such a circuit as a shield, The heavy wires that are needed for the heaters aren't mechanically compatible with Arduino shield mounting.

What you would most likely want is something called a solid state relay. They are stand alone modules that take a digital control signal compatible with Arduino digital IO and can control many 10's of Amperes, depending on which one you buy. They are available from many distributors of electronic components or companies that sell industrial controls, including baseboard heaters.. An example of a 15 Ampere device is sold by Digikey, stock # CC1161-ND --- HOWEVER!!! first determine what Ampere rating you actually need, DO NOT just order this part, I suggest it only so you can see the typical shape, and read about that type of part. If you look at other sources you will see relays that already have plastic voltage shields and are intended for easy integration into a control scheme such as yours.

Regards, dougc314

Thank you

That is helpful. When i go to PA i will check the rating of the system.

Ed

As a side note, If you want some added efficiency, add a few small fans to blow across the heating elements.

A heating element is no island to itself. You want the heat moved around the room. Ceiling fans on winter mode are good also.

Totally,
Though I do not now, I once lived in a clime where I had an electric baseboard heater and having a low-speed "muffin fan" blow across it made a world of difference.