Hello all. I'm a new user and just had a (hopefully) simple question for you. I've got a furnace at a cabin that I'd like to control remotely. I've come across some products that allow you to remotely control a relay via SMS or phone call. I was wondering if anyone had any ideas on how I could hook this up? I assume the furnace would need to continue to run, and I'd wire the relay to the thermostat input or something to trigger it to turn on?

I read in the FAQ not to post links so I will not link to the product in question unless you require more detail, but can anyone give me some pointers to get going in the right direction? Is control via GSM a bit overkill?

 

I think you can post links as long as your not trying to advertise here and drive traffic to your site.

So it sounds like you've found a solution to provide the remote-cellphone-to-relay part of the puzzle, and you're wondering where to best place your relay?

If you were in your cabin, you'd probably use your thermostat and I think that's a viable option. But on my furnace, there's a standard wall switch and I would also consider using that, mostly because it's in my basement and readily accessible. The thermostat would take a bit of research to figure out how to hack into. And thermostats come and go.

Be sure your relay is rated for the voltage and current of whatever you are switching. You should also think about how it fails, if the power goes out or you cannot contact it for some reason. Failsafes.

 

If you decide to switch the furnace power on and off be sure the thermostat isn't an electronic type that will lose its settings if the power goes off.

 

How much power should the device be able to handle to be able to switch my furnace off and on? I've found a "high amperage" device, but I don't know how much "high amperage" is...i.e. what is that relative to? As I said, not sure about the rules here, so feel free to remove this link if it violates any rules. I just need more info about what specs I need to have for a device to control my furnace:

http://relaysupply.com/gsm-relays/quad-band-high-amperage-relay-gsm-ctl-16.html

It seems like it might be overkill to switch mains power...is it dangerous to be handling "high amperage"?

 

How much power should the device be able to handle to be able to switch my furnace off and on? I've found a "high amperage" device, but I don't know how much "high amperage" is...i.e. what is that relative to? As I said, not sure about the rules here, so feel free to remove this link if it violates any rules. I just need more info about what specs I need to have for a device to control my furnace:

http://relaysupply.com/gsm-relays/quad-band-high-amperage-relay-gsm-ctl-16.html

It seems like it might be overkill to switch mains power...is it dangerous to be handling "high amperage"?

is your furnace electric? If so, how many KW (or volts & amps) is it rated? Or is it gas?

 

The relays in that device are likely rated far higher than the circuit breaker on your furnace - you should verify - so they should be more than adequate.

 

If it's a gas or oil furnace it likely takes less than 10A from a 120V mains socket.

 

I have located a very simple GSM Switch of which is low cost and comes with a Sim Card.

You can simply Plug the unit into the Mains Power socket and plug the Furnace power into the Socket on the Unit and it boots up automatically.

With this system you just call the Unit and the Furnace comes on and sends you a SMS as System On.

And to turn it off you just call it again and you get another SMS as System Off.

And it was the most cost effective unit I could find on the net.

website is www.gsmswitch.com

Hope this hepls