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-   -   How can i wire this thermostat? (http://www.diychatroom.com/f17/how-can-i-wire-thermostat-15733/)

chuey_316 01-17-2008 01:35 PM

How can i wire this thermostat?
 
I have an older 4 wire thermostat. I'm installing a corn stove soon, and i am going to tie the vent from the stove room, and master bed together with an in-line fan to help heat the back.

Now i'm sure that the fan only has 2 wires, power/ground (it's coming from a dryer). Is there anyway that i can wire the fan to my thermostat, or do i have to use a 2 wire thermostat?

Thanks for any help.

I should add that the bedroom does not have any hookup for the thermostat, so i will have to run the wires.

chris75 01-17-2008 04:34 PM

Not exactly sure what your trying to do, what is the 4 wire tstat doing now? and is the corn stove replacing or just an alternative heating system? and are you really just asking if you can turn a booster fan on from a tstat in a remote location that has nothing to do with your existing heating system?

bigMikeB 01-17-2008 06:52 PM

Well unless the fan is 24volts the thermostat isn't going to do anything for you. And adding a 24v fan load to the 40va transformer in the furnace is just going to burn it out.

WildThing 01-17-2008 08:51 PM

If I follow you
 
If I read your post correctly - you have a "4-wire" thermostat laying around your house on a shelf or something and want to know if you can use it to turn on an in-line fan you are planning on installing between 2 rooms of your house to move some heat from room 1 to room 2. I am presuming also that your thermostat is one that has 4 terminals labels R,W,Y,G ?? If that is the case, yes you can use it but will also need some other materials to complete your wiring. You will need a control transformer and a single pole relay with a 24VAC coil and contacts rated for 120VAC and for the FLA of the fan plus 20% (i.e. the fan draws 3 amps the contacts should be rated for at least 3 + .6 = 3.6 amps). NOTE: all 120VAC wiring and connection need to be in an enclosure. All that said.. here's how to wire it all. Your 120VAC power source will have a black(hot leg) and a white (neutral) wire. the fan and transformer will also have these leads. the relay will have 2 terminals for the coil and also a terminal for the power in (Line) and one for the power out (Load); sometimes these are labeled L1 and T1. the transformer will also have 2 leads supllying the 24VAC usually blue and yellow. the white from the power in, the fan, and the transformer get spliced together. THe black from the power in goes to the L1 terminal of the relay and the black wire on the transformer. The black wire from the fan goes to the T1 terminal of the relay. the blue wire from the transformer goes to one of the relay coil terminals. THe yellow from the transformer will go to the "R" terminal of the thermostat. you will take a wire from the "W" terminal of the thermostat to the other coil terminal of the relay. Finally. you need to also connect all the ground wires and connect them to a ground in that splice also take a wire from the blue transformer wire to gorund also - this will ensure that there us a ground reference for the the 24VAC.

Hope that helps you. If I missed something please post more info and I'll try to help you.

chuey_316 01-17-2008 10:17 PM

Quote:

Originally Posted by WildThing (Post 89471)
If I read your post correctly - you have a "4-wire" thermostat laying around your house on a shelf or something and want to know if you can use it to turn on an in-line fan you are planning on installing between 2 rooms of your house to move some heat from room 1 to room 2. I am presuming also that your thermostat is one that has 4 terminals labels R,W,Y,G ??

Yes this is correct. The stove is going in the family room, which will heat the kitchen, living room, and upstairs. Then the vent will suck some of the heat from the family room to the master bed, and bath.

Thank you for the explaination. It has been saved to a text document for future use.:thumbup:

Before i get what i need though, i have one other question. Would it be easier to use a 2 wire thermostat instead of the 4, or should i just go ahead with what i already have?

Thanks again. I appreciate it very much.

heavyduty 01-18-2008 12:04 PM

if your going to run a 120 volt transfer fan I would just buy a 120 volt line voltage t stat. 120 in break the blacks with t stat out to your 120 volt fan.

chuey_316 01-18-2008 01:07 PM

How about this one? http://www.prothermostats.com/produc...2&category=262

or this one i can get locally http://www.acehardwareoutlet.com/(5x...aspx?SKU=42603

bigMikeB 01-18-2008 04:43 PM

Why not just buy one of the fans made for this purpose?

chuey_316 01-18-2008 08:21 PM

I like making things myself, and i'm a firm believer in not buying what you can diy.:no:

WildThing 01-18-2008 08:48 PM

2 wire vs 4 wire vs 120VAC
 
Firstly, to answer your question. No there is no real reason to replace the 4 wire stat with a 2 wire stat. The "Y" terminal is there for Air Conditioning but it and the "G" terminal is for turning the blower on, as opposed to "auto" and given your application is also not needed, but it doesn't hurt that you are not using them.

With regard to purchasing a line voltage thermostat, yes it is an option; however, your request was replated to using what you already have. Additionally, it is most times a bit easier to run a thermostat wire (18/2) for low voltage control instead of line voltage wire such as 14/2 or 12/2 romex ( non-metallic) or MC ( Metal-clad) wire. Line voltage control will require a box just like a light switch does.

chuey_316 01-18-2008 10:10 PM

Thanks wildthing. Now this would allow the fan to kick on/off by itself? I could set the thermostat to say 68, and the fan will turn on when it gets below, and stop after it gets over, not just on/off?

Basically i'm going for simplicity, and lowest cost on this one. The wall the thermostat is going on is not drywalled. It's paneling, so installing a box wouldn't be too bad, as i can take a section down and put it back up.

I appreciate all the help, and i hope it all goes smoth when it's time to hook it up.

WildThing 01-20-2008 09:38 AM

Yes, it will cycle based on the room temperature and setpoint. If you go the line voltage route, just be sure the stat is one that "makes on fall" / "breaks on rise". This means that if the room temp falls below the setpoint the contacts inside will "make"/ close.

bigMikeB 01-20-2008 11:54 AM

Quote:

Originally Posted by WildThing (Post 89471)
If I read your post correctly - you have a "4-wire" thermostat laying around your house on a shelf or something and want to know if you can use it to turn on an in-line fan you are planning on installing between 2 rooms of your house to move some heat from room 1 to room 2. I am presuming also that your thermostat is one that has 4 terminals labels R,W,Y,G ?? If that is the case, yes you can use it but will also need some other materials to complete your wiring. You will need a control transformer and a single pole relay with a 24VAC coil and contacts rated for 120VAC and for the FLA of the fan plus 20% (i.e. the fan draws 3 amps the contacts should be rated for at least 3 + .6 = 3.6 amps). NOTE: all 120VAC wiring and connection need to be in an enclosure. All that said.. here's how to wire it all. Your 120VAC power source will have a black(hot leg) and a white (neutral) wire. the fan and transformer will also have these leads. the relay will have 2 terminals for the coil and also a terminal for the power in (Line) and one for the power out (Load); sometimes these are labeled L1 and T1. the transformer will also have 2 leads supllying the 24VAC usually blue and yellow. the white from the power in, the fan, and the transformer get spliced together. THe black from the power in goes to the L1 terminal of the relay and the black wire on the transformer. The black wire from the fan goes to the T1 terminal of the relay. the blue wire from the transformer goes to one of the relay coil terminals. THe yellow from the transformer will go to the "R" terminal of the thermostat. you will take a wire from the "W" terminal of the thermostat to the other coil terminal of the relay. Finally. you need to also connect all the ground wires and connect them to a ground in that splice also take a wire from the blue transformer wire to gorund also - this will ensure that there us a ground reference for the the 24VAC.

Hope that helps you. If I missed something please post more info and I'll try to help you.



Why add a transformer and relay that will need to be housed inside some type of enclosure when he could just use a line voltage t-stat? In my opinion a used fan from a dryer and this type of install is a homeowners insurance claim waiting to happen.

chuey_316 01-20-2008 02:24 PM

Why is that? It's no different than the ones that are sold for this same purpose to those who don't want to do fab it themselves, Like this one http://www.smarthome.com/3011.html#

Working at sears, i can tell you that many of the haul aways are in almost new condition. Especially the dryers. People tend to let there traps get clogged then buy a new dryer sure that the current one is to blame.

I can also go through and test every fan to be sure that i'm not using an old tired one, that may have problems.

bigMikeB 01-20-2008 02:27 PM

Quote:

Originally Posted by chuey_316 (Post 90287)
Why is that? It's no different than the ones that are sold for this same purpose to those who don't want to do fab it themselves, Like this one http://www.smarthome.com/3011.html#


Yeah it is way different, the ones in the link are UL approved for that specific use. End of story.


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