electrical help needed

[centennialdrive]

I'm in the middle of installing an outdoor boiler. I originally heated my house with an indoor forced-air wood furnace, and there is no LP or other form of heat, hence no existing blower.

I have built an "air handler" that contains a 110vac blower and the heat coil, and connects to my ductwork. What I need help with is getting the blower to power on from a 24v thermostat. The blower currently has no transformer or relay, and I need help understanding this electrical relationship.

Any help appreciated!

 

[mustash29]

Do you like Taco's?

Something like this should do what you need. (broken link removed to http://www.taco-hvac.com/uploads/FileLibrary/102-093.pdf)

 

[stee6043]

You can build this pretty easily with parts available off Amazon or Grainger. You need a 24V (coil voltage) relay that can handle 110V contact voltage (not sure I'm using the proper terms here, I'm no electrician) at the amperage sufficient to run your fan. If you don't have an existing furnace you'll also need a 24V transformer to create the circuit with a thermostat. Thermostats don't create the power, they just switch it.

So you would switch the hot lead from 120V to your fan with the relay. And your thermostat would switch the 24V transformer going to the coil on the relay. When the t-stat calls for heat - presto, you have a fan on.

 

[stee6043]

Ohh...and be sure to put all of this fanciness in a suitable electrical enclosure. I suspect you can do all of the above for sub $50.

 

[DIrtyJersey]

You need a 120 volt to 24 volts ac transformer 40 or a 30 VA. with a contact. Or use a line voltage thermostat. You could add a switching relay to add two speeds. Also if power loss is often you could add a delay control as not to slam on and off during power losses. Hope this helps.

Low voltage t-stat
RH-RC = 24v primary. Usually has a small jumper in place.(Red wire)
G=Fan (Green wire)
W= Heat (White Wire)
Y= Cooling (Yellow Wire)
Blk=Common

Or as stated Line voltage T-stat. Wired like a single pole switch. Black on the poles of the switch. Neutral wires bugged together then. Ground it.

 

[hockeypuck]

As licensed electrician, I would probably stick with the Taco controller. UL listed.. therefore you would not have any problems from a militant electrical inspector.

 

[alaskawild]

Use the Taco controller! If you are an experienced electrician and like to tinker go the granger route but if not don't do it!

 

[centennialdrive]

Thank you all for the replies! I got directed to a local industrial electrical motor supply who hooked me up with the proper transformer, relay and instructions. Hooked it all up yesterday to a thermostat and it worked like a charm.