Firepower 2230 Add On furnace - wiring diagragm

ionfuel

New Member
Dec 20, 2020
14
NW Ohio
Hello - I've seen one other post on this forum about this furnace. I've have it for many years and it has worked great until a couple of weeks ago. The main blower stopped working (just a humming sound). I suspected the motor was binding. I unwired the two wire main blower to remove it from the housing. It did not turn easily so I knew it needed lubricated. I did that and got it working/turning freely again. But after re-installing and re-wiring, the main blower doesn't turn on when the furnace gets up to temp.

It has a Honeywell 4 terminal fan limiter (pic attached), Honeywell R8285A Control unit (pic taken from top attached) and a second transformer (pic attached).

The R8285A controls a 120V damper blower in front of the furnace and it works ok; I turn up the thermostat and that turns the damper blower on. The main blower's two wires are connected to the 120v source power black and the other was originally connected to the white wire coming back from the limited and a white neutral wire that goes to the second transformer.

The transformer pic shows the black and white wires and a small blue wire that is jumped back to the top of the control unit. If I test the black and white wires on the transformer before the furnace is gets to operating temp, I read about 34V. Then when the furnace gets to operating temp based on the limiter setting, I get almost 0v on those two wires. I'm not sure what the purpose of the small small blue wire jumped back to the control unit does.

As an interim fix, I have the main blower wired to a separate power line, so that I can turn off and on with a switch right inside the basement door. So now the main blower is either always on or always off based on that switch (no fun) and I am stumped on why when originally rewired. the main blower does not turn and off anymore.

If anyone has seen a wiring setup like this (perhaps the guy who posted on this same model back in 19' knows) and has any ideas, that'd be great to know!

Honeywell Fan limiter.JPG Top of Honeywell R8285A.JPG Transformer.JPG
 

brenndatomu

Minister of Fire
Aug 21, 2013
6,022
NE Ohio
What is the brown plastic looking block in the 3rd pic with the black, white, and small blue wires on it? Not familiar with that piece...
Will the blower run if you push the manual mode pin? (the white square plastic pin on the lower left side of the fan control/limit switch)
If it doesn't, it should...
 

ionfuel

New Member
Dec 20, 2020
14
NW Ohio
Hello - that 'block' looks to be a transformer but I don't think it gets 120v. When I re-wired the main blower back to the way it was, pushing the pin in did not turn on the blower (it used to however...).
 

brenndatomu

Minister of Fire
Aug 21, 2013
6,022
NE Ohio
Hmm...that brown block has me puzzled...is there any brand or part/model number info on it?
Ok, so you should be able to take your multimeter and see which wire becomes hot when you push that pin (make sure one of the wires is hot (120V) coming into the fan/limit switch first...can't switch on what you don't have to begin with) then you can follow that wire to see where you are losing power. Don't forget to make sure you have continuity on the white common wire to the blower too.
FYI, there may be 24V coming into the fan/limit too...but maybe not on this one since you said the combustion air blower is 120V...dunno.
 

brenndatomu

Minister of Fire
Aug 21, 2013
6,022
NE Ohio
This is a decent video on the Honeywell FLS...just substitute your combustion blower for "burner"...and when he says fan, that means the large heat duct blower that you are trying to fix...
 

ionfuel

New Member
Dec 20, 2020
14
NW Ohio
Here is how the fan/limit switch should be wired...
View attachment 270009
Hi and thanks for this. In my case, the 'fan motor' is my damper blower. The limiter does not have a jumper, so the 24V transformer makes sense. It would seem as if I need two limiters; one for the damper blower and one for the main blower but since there is only one, the 'mystery' transformer has something to do with it. I'll do some more meter tests to see which wire becomes hot when I push the pin.
 

brenndatomu

Minister of Fire
Aug 21, 2013
6,022
NE Ohio
Hi and thanks for this. In my case, the 'fan motor' is my damper blower. The limiter does not have a jumper, so the 24V transformer makes sense. It would seem as if I need two limiters; one for the damper blower and one for the main blower but since there is only one, the 'mystery' transformer has something to do with it. I'll do some more meter tests to see which wire becomes hot when I push the pin.
Well the damper blower (combustion air blower on the front) should be controlled by the thermostat...and ultimately the limit switch, if things ever got that hot) the main blower (warm air into the house) should really only be controlled by the Honeywell FLS...there is no need for a "limit switch" for it, since if it sticks on, the only potential harm would be a cold draft in the house...;lol
 

ionfuel

New Member
Dec 20, 2020
14
NW Ohio
Well the damper blower (combustion air blower on the front) should be controlled by the thermostat...and ultimately the limit switch, if things ever got that hot) the main blower (warm air into the house) should really only be controlled by the Honeywell FLS...there is no need for a "limit switch" for it, since if it sticks on, the only potential harm would be a cold draft in the house...;lol
Yes, the damper blower is controlled by the thermostat in the home; I turn up the thermostat, the damper blower turns on as it should; if the furnace gets too hot, the limit switch turns it off and it does. All of that is still working; the main blower would turn on when the furnace reached its temp; that's the part of the setup that is now not working.
 

brenndatomu

Minister of Fire
Aug 21, 2013
6,022
NE Ohio
Yes, the damper blower is controlled by the thermostat in the home; I turn up the thermostat, the damper blower turns on as it should; if the furnace gets too hot, the limit switch turns it off and it does. All of that is still working; the main blower would turn on when the furnace reached its temp; that's the part of the setup that is now not working.
Right, so now its just a process of elimination to see if the FLS is bad, or a wiring issues, etc...should be able to just"jump" the FLS to eliminate it as the culprit...or not, as the case may be...
 

ionfuel

New Member
Dec 20, 2020
14
NW Ohio
Right, so now its just a process of elimination to see if the FLS is bad, or a wiring issues, etc...should be able to just"jump" the FLS to eliminate it as the culprit...or not, as the case may be...
I'll do some more tests with my meter and will advise what I hopefully find. Thanks.
 
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ionfuel

New Member
Dec 20, 2020
14
NW Ohio
Right, so now its just a process of elimination to see if the FLS is bad, or a wiring issues, etc...should be able to just"jump" the FLS to eliminate it as the culprit...or not, as the case may be...
Hello - so when I use my meter to test the fan terminals on the FLS left side while the furnace is at operating temp, touching the black wire terminal and any part of the furnace metal chassis gives me a 120v reading (makes sense). If I test both fan terminals (white and black wires) on the FLS while is at operating temp, I think I should also get a 120v reading, but I am not. Is that an indication the FLS is bad?
 

brenndatomu

Minister of Fire
Aug 21, 2013
6,022
NE Ohio
When testing the left (fan control) side, you should have 120V when you touch your black wire and ground...you should also get 120V when either, the furnace is hot enough to kick the blower on, or, when you push the white pin in...testing at the white wire and ground.
If you have 120V at the lower left wire, but none at the upper left wire (when pushing pin, or hot enough to run blower) then yes, the FLS is bad.
You can verify this additionally by getting a short piece of wire (single conductor like you have there is best/easiest) strip a bit of insulation off both ends, bend it in a U shape and jam the ends in there where the left two wires connect (try to make contact with the wires or the switch terminals) it might arc or spark just a bit (you'll be fine if you just hold onto the insulated wire) but the blower should start when you do this, no matter what temp the furnace is...this would duplicate what pushing the white pin does, except you are now bypassing the switch itself.
If this test makes it run, then yes, switch definitely bad. (Unless the wires have a bad connection where they plug in the FLS there...that's possible too...but if everything looks good when you take them out, chances are that's not it)
 
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ionfuel

New Member
Dec 20, 2020
14
NW Ohio
Yes, that's what it's beginning to sound like. Do you know what goes bad with an FLS like that? A burnt wire or something in it that burnt out? Obviously not a fuse or anything like that.
 

brenndatomu

Minister of Fire
Aug 21, 2013
6,022
NE Ohio
Contacts burnt up would be my guess...it was probably overloaded when your blower motor was struggling to start...that makes the motor draw huge amperage for extended periods (compared to normal) and the extreme load on older components is a good recipe for things to get fried.
 

ionfuel

New Member
Dec 20, 2020
14
NW Ohio
Contacts burnt up would be my guess...it was probably overloaded when your blower motor was struggling to start...that makes the motor draw huge amperage for extended periods (compared to normal) and the extreme load on older components is a good recipe for things to get fried.
OK. That makes sense. Then on the morning the motor was locked up for many seconds before power was turned off, that's when the damage was done. I just took the FLS off the side; it has the 5" length probe and Amazon appears to have it.
 

ionfuel

New Member
Dec 20, 2020
14
NW Ohio
I wired the main blower back to its original setup, pushed in the white pin on FLS, took a wire and jumped the two left wires (pushing the wire ends into the left terminals) then the power and on and...blower did NOT turn on. Now I'm confused.
 

ionfuel

New Member
Dec 20, 2020
14
NW Ohio
I took the other little transformer off (rightmost pic in my thread). That is a Honeywell R8222d 1014 24v relay transformer. The motor overload could have messed it up too. I think what happens is, when the main blower turns on (original wiring), that transformer gets power and the little blue wire sends 24v to the control unit. It's making sense now; I either have a bad FLS, R8222D transformer, or both.
 

brenndatomu

Minister of Fire
Aug 21, 2013
6,022
NE Ohio
Well, if jumping the FLS contacts didn't make it start then there must be another issue...jump the FLS out and follow the wire, see where you lose power...then make sure the common (white) wire at the blower motor is good too. Doesn't help that they used a white wire for power to the motor coming out of the FLS...should have been just about any other color than white!
Did you ever look for any data on that brown thing?
 

ionfuel

New Member
Dec 20, 2020
14
NW Ohio
Well, if jumping the FLS contacts didn't make it start then there must be another issue...jump the FLS out and follow the wire, see where you lose power...then make sure the common (white) wire at the blower motor is good too. Doesn't help that they used a white wire for power to the motor coming out of the FLS...should have been just about any other color than white!
Did you ever look for any data on that brown thing?
Yes. That is a Honeywell R8222d 1014 24v relay transformer.
 

brenndatomu

Minister of Fire
Aug 21, 2013
6,022
NE Ohio
Why the heck is there 2 transformer/relay assemblies?! Is the original R8285A bad and someone just scabbed in a second replacement one?
This is getting hard to troubleshoot from afar...if that R8222d was added on by someone later (and it surely was...this furnace is too simple to need more than the original R8285A) its really hard to say what someone did here...about the only thing you can do is lay it all out on paper, as far as what wires go where, and see if you can make sense of it enough to nail down a failed component...hate to just start throwing new parts at something without knowing what's failed...that usually gets unnecessarily expensive...
 

ionfuel

New Member
Dec 20, 2020
14
NW Ohio
I think the R8222d is there for a reason. I need to test it with a separate 120v source to make sure it works. I'll see if I can make a diagram and post it. Thanks.
 

brenndatomu

Minister of Fire
Aug 21, 2013
6,022
NE Ohio
I think the R8222d is there for a reason. I need to test it with a separate 120v source to make sure it works. I'll see if I can make a diagram and post it. Thanks.
Maybe...but my old Yukon Big Jack furnace was exactly like this unit...120V combustion air blower on the front, 120V main duct blower on the back...and it just had a Honeywell FLS, and a Honeywell transformer/relay assembly...that was it for controls, except the tstat upstairs...that would be a very typical setup...if this dual transformer/relay setup is original, it is atypical for sure...
http://www.yukon-eagle.com/pdfs/jack.pdf Wiring diagram on page 13
 

ionfuel

New Member
Dec 20, 2020
14
NW Ohio
Thanks for that. That diagram shows a jumper on the FLS; my FLS does not have the jumper in it so my limiter is 24v controlled (I think) and perhaps that's why the R8222D is there along with the other relay. I appreciate all of the help.