# how to wire my thermostat for blower to run for out door wood boiler heat?



## troy21 (Dec 11, 2011)

i have a outdoor wood boiler, iv got it all hooked up heat exchanger in the furnace exc...now im having truble fixing my t-stat so the blower will run when i need heat, i have a central heat and air unit, with the heat side being propane, now the propane part of this furnace is not hooked ,up its shot, so with that being said i don't care about if my propane works exc, all i want is ac to work in the summer and the blower to kick on and off when house temp is right in the winter for the outdoor stove, now how do i get the thermostat i got wired so the fan will kick on and off when i need heat and don't my t-stat has a auto and a on for the blower, the wire colors in the t-stat are, green wire to g on the t-stat, red wire to rc on t-stat and blue wire to rh on t-stat and white to w on the t-stat and yellow to y on t-stat, and the rh uses a jumper wire back to the rc???? so how do i wire this so my blower will kick on and off whhen my t-stat hits the right temp? and my ac still work right?,,, ps thanks for all advice,, time are hard and i aint got extra money to pay a hvac man, so i gotta learn this my self. so thanks for all help


----------



## cr4west (Dec 12, 2011)

Most propane and gas furnaces are wired so that the circulation blower only comes on after the unit has been burning gas for a short time to pre-heat the heat exchanger up to operating temperature. Remove the cover from your propane furnace and usually there will be a diagram of the electrical circuit on the inside of the cover. With the understanding that the heating mode has this built in temperature delay you are faced with two choices: 1. Modify the heat mode circuit to bypass the temperature delay. This is done by a temp sensor that looks like a round disk the size of a silver dollar with two electrical terminals usually mounted on the hot metal plenum. -or- 2. Install a two way switch into the cooling mode circuit that will act as a "season" selection between heat and cooling. Usually the cooling side has no temperature delay and the circulation blower operates immediately upon demand from the thermostat. The purpose of the added switch is to disconnect the AC compressor during cold season and switch power to turn on something required to operate your wood boiler side, perhaps a circulation pump or a signal light that says "add more wood to the boiler now"


----------



## Doghouse (Dec 12, 2011)

Easiest thing to do is to add a second, two wire thermostat to just the fan wires. Or switch the fan wires to the heat terminals in your current thermostat and then switch them back for the summer.


----------



## 1grnlwn (Dec 12, 2011)

More than likely your control circuit is 24VAC . Use a volt/ohm meter to determine which wires are hot when thermostat calls for heat. It is probably one of the wires running to the gas valve. If there is a thermal switch after the gas valve a wire should run from the gas valve to the thermal switch. If you are not going to use gas as a back up you could take the wire from the thermostat and connect it to the wire coming from the thermal switch to the fan relay. This would bypass the gas valve and the thermal switch and send the 24 V signal directly from the thermostat to the fan relay. Now, since I only pump water when I am calling for heat, I have a 24V relay tied in to the fan signal which actuates my 120V pumps. The 120V side of the relay is attached to a cord which I just plug into an outlet in the utility room. When cooling season is here I just unplug the cord and close my water valves. Now if you want to keep the gas as a back up you could use a switch to bypass the valve and therm switch. I believe a three pole switch center pole which goes right or left. Right normal path left boiler path. Just remember the DIY creed... You may get yourself in so much trouble that you will have to call a professional. If you do, you will pay more and he will laugh at you!


----------



## troy21 (Dec 12, 2011)

ok so my propane is shot, burnt out i cant use, so i dont care about the back up, i just need my blower to run and kick off when temp in the house is right, so what wires do i cross or how do i wire a second thermostat in to by pass all the gass since its not working


----------



## 1grnlwn (Dec 12, 2011)

Go to the closest bar and shout who is a HVAC guy (there is one in every bar) offer him a case of beer to come over and wire it for you.


----------



## troy21 (Dec 12, 2011)

lol, this cant be that hard, all i need is for the fan to kick on at x temp and kick off at x temp in my home, what do i cross to do this, do i jump the green to the the rh? will this alow the t-stat to kick the fan off and on at x temp


----------



## 1grnlwn (Dec 12, 2011)

If it is not that hard why are you on here asking us how to do it? Is there standard thermostat wiring? Yes! Is yours wired to standard? Who the heck knows? You will be hard pressed to find a HVAC professional on here to give free wiring advice, or any other site for that matter. There can be serious consequences if this stuff is done incorrectly. So either do some homework and learn how the system works so you can make your modifications or suck it up and pay the Guy!


----------



## 1grnlwn (Dec 12, 2011)

Ok young man, now that you have had your cyber spanking, I will do your homework for you. According to the website Thermostat Wiring You should remove the wire from the W terminal, it will not be used. Take a jumper and run it from the W terminal to the G terminal. That should do the trick.


----------



## CJ1 (Dec 12, 2011)

Doghouse said:


> Easiest thing to do is to add a second, two wire thermostat to just the fan wires. Or switch the fan wires to the heat terminals in your current thermostat and then switch them back for the summer.



Yup, thats the best way. But you need to disconnect the fan wire from your main stat or the A/C will kick on. [backfeed] So in short, connect 1wire fron the aux stat to the common hot of the main stat, then unhook the fan wire and hook directly to the other wire from the Aux stat. CJ


----------



## mtfallsmikey (Dec 12, 2011)

1grnlwn said:


> If it is not that hard why are you on here asking us how to do it? Is there standard thermostat wiring? Yes! Is yours wired to standard? Who the heck knows? You will be hard pressed to find a HVAC professional on here to give free wiring advice, or any other site for that matter. There can be serious consequences if this stuff is done incorrectly. So either do some homework and learn how the system works so you can make your modifications or suck it up and pay the Guy!


1grnlwn
That is correct. I will not be held liable if I tell anyone how to do that, especially with the newer furnaces that have all conttrols on a single PC board. 1grnlwn may be correct with his theory, depending on the make of furnace, and the control setup. I used a separate relay/transformer to control the fan and secondary circuit circ. pump with the separate thermostat on mine, but i had all of the parts laying around. If nothing else, you could wire the 120v. side of the blower thru an electric heat t-stat. I did that with the heater I made from an old gas furnace for the garage.


----------



## superwd6 (Dec 12, 2011)

you guys make me laugh. If your to cheap to get somebody, you hook your second thermostat To RC and G. This turns on the fan but if your Ac stat is in the AUTO position it will backfeed 24 volts and turn on AC. Short term solution is to turn 220 volts off to the A/c till you get somebody to wire in an isolation relay properly. DON"t try and wire 120 volt stat , if you send power to more than one speed on direct drive motors you will cook the motor.Good luck with HVAC guys as we have bad ones just like doctors LOL


----------



## troy21 (Dec 12, 2011)

1grnlwn
thank u, after seeing that sight i thaink u are right, im only worried that the safty switch or the flam sensor will cause this not to work.. but i dont know , this unit is a frigadare unit, i belive if im reading it right that the g is the blower and jumping it to the w will alow the fan to kick on and off?? im gessing i just put my t-stat on heat then should the fan kick on and off as temp is reached? im trying to learn this..dont kow if i will ever do this again,lol but trying thanks for the cyber spanking guys.. so shold this work w wire not used, and jump w to g?


----------



## katcarving (Nov 26, 2012)

*diagram picture for thermostate switch over from wood boiler to funace temp switch*



1grnlwn said:


> More than likely your control circuit is 24VAC . Use a volt/ohm meter to determine which wires are hot when thermostat calls for heat. It is probably one of the wires running to the gas valve. If there is a thermal switch after the gas valve a wire should run from the gas valve to the thermal switch. If you are not going to use gas as a back up you could take the wire from the thermostat and connect it to the wire coming from the thermal switch to the fan relay. This would bypass the gas valve and the thermal switch and send the 24 V signal directly from the thermostat to the fan relay. Now, since I only pump water when I am calling for heat, I have a 24V relay tied in to the fan signal which actuates my 120V pumps. The 120V side of the relay is attached to a cord which I just plug into an outlet in the utility room. When cooling season is here I just unplug the cord and close my water valves. Now if you want to keep the gas as a back up you could use a switch to bypass the valve and therm switch. I believe a three pole switch center pole which goes right or left. Right normal path left boiler path. Just remember the DIY creed... You may get yourself in so much trouble that you will have to call a professional. If you do, you will pay more and he will laugh at you!



View attachment 264185

thought this might help:bang:


----------



## Dogsout (Nov 26, 2012)

Doghouse said:


> Easiest thing to do is to add a second, two wire thermostat to just the fan wires. Or switch the fan wires to the heat terminals in your current thermostat and then switch them back for the summer.




This still seems to be the easiest in my book. This is what I did and it works great. Only I didn't want a fan to cycle on and off I have my second stat hooked to just turn my furnace pump on and off as the house needs heat from the ODW.


----------



## Butch(OH) (Nov 26, 2012)

Forced air furnace control wiring is not ultra complicated but you can screw things up if you randomly connect wires. The systems use a common code, First thing you need to do is go to Google or similar and punch in furance thermostat wiring or similar and study for 10-15 minites so the terms used makes sence.

Now, adding a second thermostat to control he fan only for the OWB does not require relays to keep the A/C from running nor do you have to throw breakers, pull fuses or do anything else that is out of the ordinary. It is not compilcated to install nor operate and it is not expensive. The key to all this is your OWB fan controll thermostat is installed in SERIES with the indoor furnace control circuit not in parallel. I have installed 4 now including my own and "fixed" 2 others that were installed wrong and all work perfectly. Here is how I do it.
First thing is your indoor furance thermostat must have a "fan on" feature, if it doesnt you must buy a new thermostat that does have that feature and install it. Last I bought was digital and $12 at Lowes. Again I am not going into the wiring here as it gets too long winded and depends on your furnace controller type. Nice instructions come wih the 'stats too. You do this prior to adding Thermostat number 2 then once you have your indoor furnace up and going with your new thermostat you are ready to proceed to the easy part, wiring up the 2nd thermostat to control the fan when running the OWB. Find the two wires that are connected when you sellect Fan On. One of them will have control voltage at all times, the other will have it only when you have selected Fan-On. Cut the wire that does not have voltage all the time and attach a wire to both ends you just cut that is long enough to reach your second thermostat. Your second thermostat is wired for heat only, again read the instrcuctions that come withthe stats and attach the two wires as instructed. This is what I meant earlier when I said that your OWB thermostat connected in seires not parallel. 

To operate the system 
Basicaly what you just did is break into the fan-on circuit with a second control, your OWB thermostat. The fan-on feature of your indoor furance thermostat should now be thought of as OWB ON or OFF. To operate you set fan-on switch on thermostat number 1 to ON. You then set the temperature with thermostat number 2. You can set your indoor furnace heat all the way down or set it a few degrees under the OWB thermostat so it will automaticaly heat the house if your OWB runs out of wood or pumps fail. In the summer you set the fan-on switch to OFF and use the indoor furance thermostat to controll the A/C just like nothing was changed. The only thing that happens out of the ordinary with this set up is when the second thermostat calls for heat the fan is going to run no matter if there is heat in the loop or not. If you wish and dont mind the added complication you can add a switch that monitors the loop temps and wire it in (also in series) with your OWB thermostat. That way the fan will not run until the loop temps reach "X" temp. 

It is always hard for me to make this sound as simple as it realy is. Hope I have helped and not hindered.


----------



## katcarving (Nov 26, 2012)

Butch(OH) said:


> Forced air furnace control wiring is not ultra complicated but you can screw things up if you randomly connect wires. The systems use a common code, First thing you need to do is go to Google or similar and punch in furance thermostat wiring or similar and study for 10-15 minites so the terms used makes sence.
> 
> Now, adding a second thermostat to control he fan only for the OWB does not require relays to keep the A/C from running nor do you have to throw breakers, pull fuses or do anything else that is out of the ordinary. It is not compilcated to install nor operate and it is not expensive. The key to all this is your OWB fan controll thermostat is installed in SERIES with the indoor furnace control circuit not in parallel. I have installed 4 now including my own and "fixed" 2 others that were installed wrong and all work perfectly. Here is how I do it.
> First thing is your indoor furance thermostat must have a "fan on" feature, if it doesnt you must buy a new thermostat that does have that feature and install it. Last I bought was digital and $12 at Lowes. Again I am not going into the wiring here as it gets too long winded and depends on your furnace controller type. Nice instructions come wih the 'stats too. You do this prior to adding Thermostat number 2 then once you have your indoor furnace up and going with your new thermostat you are ready to proceed to the easy part, wiring up the 2nd thermostat to control the fan when running the OWB. Find the two wires that are connected when you sellect Fan On. One of them will have control voltage at all times, the other will have it only when you have selected Fan-On. Cut the wire that does not have voltage all the time and attach a wire to both ends you just cut that is long enough to reach your second thermostat. Your second thermostat is wired for heat only, again read the instrcuctions that come withthe stats and attach the two wires as instructed. This is what I meant earlier when I said that your OWB thermostat connected in seires not parallel.
> ...


this will work if you haven;t already used other side of thermo for central air ,this is the reason for picture plan for new themnostatView attachment 264218


----------



## Butch(OH) (Nov 26, 2012)

Since I am not an HVAC guy I dont know what you mean by the other side of the thermostat? In my case and the others I helped the forced air furnace and the A/C is on one thermostat and you move a switch to go between heat and A/C. Some had a fan on feature on the thermostat and some didn't until I changed it. I reasoned that since I could flip the fan on switch and not have the AC running that I could control that same circuit with another thermostat instead of the thumb switch and it worked, at least have not run into problems on the several I have done, some were single speed some including mine are variable speed. Fan-on always runs the fan in high speed which is usualy desireable withthe heat excahnger in the plenum anyway. I think? (been a couple years) that fan on connects the R to the G?


----------



## mtfallsmikey (Nov 27, 2012)

katcarving's diagram is correct. I used a separate t-stat, xmfr., relay I cabbaged out of an old heat pump air handler to do mine.


----------

