How to wire oil furnace for use with w/a heat exchanger and one thermostat

[Newvigasowner]

So i want to use one thermostat to control my oil forced air furnace and my heat exchanger coil fed from wood boiler in garage. Is this possible to do? I think I have thought of a way to do it but i am unsure if it is actually possible. Here it goes, i have a ranco temperature controler that will monitor my storage tank temp say set to 130°,(i have cable running from house to garage) so when temp is above that i would have power via the ranco relay in the house to my circulator, and taco switching relay and would like to install a relay somewhere on my oil furnace to stop the burner from firing but maintain the fan control to provide air circulation thru heat exchanger controlled by the thermostat . If temps on storage tanks were to fall below 130° it would open the ranco circuit, killing power to circulation pump, taco switching relay and close the contact on the relay that is installed somewhere on the oil furnace, and furnace would operate like normal. Hopefully it's not too hard to understand, basically i need to find a way to stop the oil burner from firing if that's possible. It's an olson oil furnace with Beckett burner, I've attached wiring diagram of furnace. Any help would be great, thanks

 

[Clarkbug]

Your first picture of the burner shows a R-W going to the TT terminals of the oil burner. You would want to interrupt that wire and put in a relay thats tied in to the signal controlling your circ pump.

 

[Newvigasowner]

Your first picture of the burner shows a R-W going to the TT terminals of the oil burner. You would want to interrupt that wire and put in a relay thats tied in to the signal controlling your circ pump.

But would the furnace fan still operate normally if i break the TT terminals?

 

[Clarkbug]

You only want to break the signal from the furnace controller to the TT terminals on the oil gun, not the signal from the thermostat itself.

I have a controller that does something similar for my system. It uses an aquastat mounted on my storage tank, and based on that either opens or closes a relay that interrupts the signal to the oil gun. When the tanks are hot, the zone controller and associated circ pumps work just fine. When they are cold, it closes the relay and the system works like I dont have wood at all.

Your furnace fan should cycle the same as it would otherwise, since all of the associated burner functions (flame sensor, oil valve, etc.) are going to signal off of the TT connection.

 

[Newvigasowner]

You only want to break the signal from the furnace controller to the TT terminals on the oil gun, not the signal from the thermostat itself.

I have a controller that does something similar for my system. It uses an aquastat mounted on my storage tank, and based on that either opens or closes a relay that interrupts the signal to the oil gun. When the tanks are hot, the zone controller and associated circ pumps work just fine. When they are cold, it closes the relay and the system works like I dont have wood at all.

Your furnace fan should cycle the same as it would otherwise, since all of the associated burner functions (flame sensor, oil valve, etc.) are going to signal off of the TT connection.

I tried disconnecting both wires one at a time from the tt location and furnace fan would not come on when thermostat was calling for heat, do i have to reroute it somewhere else to complete a circuit?

 

[Clarkbug]

Hmm. Further review of the second diagram (sorry, should have started there...I just worked from left to right!) shows that there is a fan limit control in there also. So, it looks like its not as easy as I had made it out to be, my apologies there.

Ill have to stare at your schematic for a while to figure out what might make more sense. Hopefully someone smarter than me can chime in and save us both.

 

[Clarkbug]

So, do you know what limit controller you have? Says there are a few different options here.

(broken link removed to http://www.ecrinternational.com/secure/upload/document/3375.pdf)

There is a delay between the call for heat and the operation of your fan so you dont get cold air blowing from your ductwork.

 

[Newvigasowner]

[quote="Clarkbug, post: 1808742, member: 1633o, do you know what limit controller you have? Says there are a few different options here.

(broken link removed to http://www.ecrinternational.com/secure/upload/document/3375.pdf)

There is a delay between the call for heat and the operation of your fan so you dont get cold air blowing from your ductwork.[/quote]
I believe its the honeywell mechanical unit, little dial with 3 setpoints, is that what ur asking me for?

 

[Newvigasowner]

More pics

 

[STIHLY DAN]

Just get a t-stat that has the ability to switch to electric heat. Then the stat will run the fan in heat not the unit. If you get 1 with a built in delay, even better.

 

[Clarkbug]

Does your t-stat now allow you to just run the fan manually?

 

[Newvigasowner]

Just get a t-stat that has the ability to switch to electric heat. Then the stat will run the fan in heat not the unit. If you get 1 with a built in delay, even better.

Would this switch back and forth automatically... Coul you provide a model or link cant seem to find anything online

 

[Newvigasowner]

Does your t-stat now allow you to just run the fan manually?

Yes it does

 

[STIHLY DAN]

Would this switch back and forth automatically... Coul you provide a model or link cant seem to find anything online

No, you would still need an aqua stat to open tt on the burner when you are burning wood. But any time t-stat called for heat fan would turn on, no matter which unit was providing heat. Off hand , don't have a model, but must Honeywell fision pro's have the ability to set for gas, oil, or electric.

 

[brenndatomu]

Honeywell fision pro's have the ability to set for gas, oil, or electric.

You mean Honeywell FocusPros? The 5000 and 6000 models do that. Heck, you can get the 6000 wifi capable! There was a thread here somewhere a while back about a review on amazon or somewhere like that about a guy that used the wifi 'stat to screw with the x wife in his old house, it was hilarious! I'll hafta see if I can find it...here it is https://www.hearth.com/talk/posts/1763345/
Sorry, I know, off topic, but SO worth reading! (gotta read the comments too, almost as funny as the review)

 

[Newvigasowner]

You mean Honeywell FocusPros? The 5000 and 6000 models do that. Heck, you can get the 6000 wifi capable! There was a thread here somewhere a while back about a review on amazon or somewhere like that about a guy that used the wifi 'stat to screw with the x wife in his old house, it was hilarious! I'll hafta see if I can find it...here it is https://www.hearth.com/talk/posts/1763345/
Sorry, I know, off topic, but SO worth reading! (gotta read the comments too, almost as funny as the review)

Hilarious!
So i read up on 5000 and 6000 and don't fully understand how this will work in my situation. I need the oil furnace to work as normal and then somehow switch just the fan on when my boiler is up to temp, i don't wanna be switching things manually ... Am i missing something?

 

[Newvigasowner]

No, you would still need an aqua stat to open tt on the burner when you are burning wood. But any time t-stat called for heat fan would turn on, no matter which unit was providing heat. Off hand , don't have a model, but must Honeywell fision pro's have the ability to set for gas, oil, or electric.

So you think it's my thermostat that is the problem right now? My ranco would have the ability to break TT when thermostat calls for heat and this honeywell focus pro would send power to the fan without going thru any of the TT circuit ?

 

[STIHLY DAN]

So you think it's my thermostat that is the problem right now? My ranco would have the ability to break TT when thermostat calls for heat and this honeywell focus pro would send power to the fan without going thru any of the TT circuit ?

T-stat would power the fan and close tt at the t-stat, down stream your ranco will keep tt open. you are all good.

 

[Newvigasowner]

T-stat would power the fan and close tt at the t-stat, down stream your ranco will keep tt open. you are all good.

Okay, let me buy a new t-stat and then we'll come back to this, hope it works. Thanks guys, I'll keep you posted

 

[Newvigasowner]

Ok so i went out and bought 18/5 cable a new thermostat w/aux electric heat and ran the new cable figuring i needed a C wire that was gonna power the fan... Well i took a second look behind my old thermostat and a little switch there, oil or elec. Haha i switch it to elec hooked it back up and remove TT on furnace... BINGO fan runs when calling for heat. Lol thanks guys now i can return new t-stat and well i have 18/5 now incase i ever need it. The fun continues, now to get pumps wired and running.