Space heater controlled by digital thermostat

Step 5 Final assembly and testing

Before you close up the enclosure, do some preliminary testing. With nothing connected to the AC receptable, plug in the power cord. Verify that the thermostat powers up. A test lamp or small wattage light bulb connected to the outlet should be off.

Set the thermostat for heat mode and increase the set temperature above the room temperature as shown. Make sure the relay closes and 110VAC appears at the outlet, or the lamp turns on. If it checks out, test it with a real space heater, and allow it to run at least half an hour on your bench. Turn it off and inspect for any overheated wires or hot components.

If everything checks out, congratulations! You now have a digitally programmable space heater!

Comments

[manicmonday]

This is a great instructable. It's easy to build, the parts are not expensive, and it helps a person save power, and therefore save money. It's great that you are so helpful when a person trying this runs into a snag. Only weak point is that the schematic is not very clear where it comes to the relay, but then you explained in the comments.

I gave you a 5 Best Instructable Ever.

Just wondering though, if you (mightyohm) is the author, why does it list P914 as the author?

Thank you for the great instructable, and your help with it.

[mightyohm]

Long story short, I wrote this instructable a very long time ago under a different username.  I don't use p914 anymore and use mightyohm instead.

[sparkyskarts]

Awesome Set up, and Idea!! Thanks for sharing!
  Have you tried this in "Cooling" Mode, and plug in a portable air conditioner instead? I'm sure it is possible, just not sure how the wiring currently controls it all. Does it bypass the Controllers cooling portion, or is it one in the same?
Please advise, as I have a real need for a portable air conditioning controller. Your work is perfect!!
Thanks again!

[mightyohm]

I haven't tried using it for cooling, as I don't own an air conditioner.  However, simply moving the E/W1 wire to the Y1 position will convert this heating controller into a cooling controller instead!  Of course, while the terminal names are fairly standardized, your thermostat may be different.  Check your thermostat's user manual to make sure the wiring is correct for you.

[manicmonday]

For cooling wouldn't you do the exact same thing, but at the thermostat connect to the cooling screw? If you wanted one of these that did both heat and cool, then you would either jumper the heat/cool screws, or build a seperate relay assembly and run that off of the cooling wire from the thermostat. Do you think I am correct?

[sparkyskarts]

I thought about that too. The 'Y' connection works great for A/C. When you get your Thermostat, it will have a Pin out for each item. Mine did NOT use C, because it has it's own battery power. It had 2 connections for 'R' (Rc & Rh), which were jumpered together from factory. I left the jumper in place, and used 'Rc' and 'Y' for Cooling, and it works great. The Temp Controller actually had about 5 different ways to connect it up, depending on your system! I would say  build a separate Relay assy, for the Heat, since the trigger for each is different.
Good Luck!

[mightyohm]

Yep, while I've never tried it, I think you are correct!

[sparkyskarts]

Perfect!! Thanks soo much! I was hoping it would be as easy as that. I am not at all familiar with the pin out of a Temp. controller. I'm sure I can get it to work that way now, Great Instructable, I'll try to do my first instructable on the A/C version, as someone might still want to cool some rooms, it has been in the Low 90's around my house still, and will here and there all winter. Of course, you get all the credit!!
A++ Idea

[markj11]

 Just what I was looking for.  I have gas logs that have on/off(light switch) on the wall that I want to replace with a thermostat.  Thanks. 

[gregoryheller]

It occurs to me that you probably do not want to measure the temperature at the floor of your room, but rather somewhere around 4 or 5 ft off the ground. Could you just extend the thermostat wires and hang the thermostat on the wall?

[mightyohm]

Yes, or do what I did and set the thermostat/relay box on top of a bookshelf or tall chair.