# Bryant Plus 90 furnace Blowers Constantly on.



## MaximYuryev (Dec 24, 2011)

Hey guys, I looked through a couple threads on this forum about this same or similar issues, did some troubleshooting steps and nothing helped. 

I found a burnt solder spot, where the relay pin was soldered, I cleaned it and resoldered it and also a couple visible bad solder connections on the board and that didnt help. 

After this I ordered the two relays online for cheap (there are two side by side on my control board *Hk42FZ011*) thought one or both may be welded shut. Replaced them and nothing.. *If I pull the white Blower wire on the control board the blower turns does turn off.* 

I ordered a new control board. Its a replacement for mine, http://www.air1supply.com/ICM282-Furnace-Control-Board-REPLACES-CARRIER_p_115.html

Just installed it and the issue remains. Blower constantly on when there is power to the furnace. 

We've been using the power switch (looks like a light switch) to turn the furnace off once the house heats up to 70. I know the thermostat is working fine. I pulled it off the wall and nothing changed, blower was still on. My Father gave me a new one also (he had a spare) and same problem. 

Any help would be greatly appreciated! Thanks!


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## ben's plumbing (Oct 6, 2011)

did you try disconnecting the stat wires off board...and powering the unit up..this will eleminate stat,subbase,and wiring to stat.....


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## MaximYuryev (Dec 24, 2011)

Yes I did try that, on the old board and new one.


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## qbert (Mar 23, 2009)

Did you test the limit switch before replacing board


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## ben's plumbing (Oct 6, 2011)

not sure on this model furnace....see if there is safty roll out switch in blower box on either side of blower...these trip and cause blower to run all the time...


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## how (Feb 26, 2011)

I'd be looking at the limit, safety roll out switches or lightly tapping the board fan relay to see if it was sticking But......
I just came from a customer complaining about the same problem but it turned out that what they thought was an on/off switch(looked like a light switch) for the furnace was actually wired up as a summer fan switch. So the just in case your thermostat is set for 20 when you are shutting off that switch... Can the furnace still fire up when the thermostat is calling for heat and that switch is off?


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## yuri (Nov 29, 2008)

It has a high temp limit switch below the burner box and should look like this one. Will cause the fan to run non stop if it is stuck open from overheating/poor airflow.


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## ben's plumbing (Oct 6, 2011)

yuri...he said he turns switch on and off to heat house....if limit was open would the inducer and igniter still work???????? not real familiar with bryant


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## Doc Holliday (Mar 12, 2011)

The only reason blowers blow consistantly is due to a high temperature limit switch tripping, meaning your furnace overheated. You can replace the limit switch or reset it if it is resettable but most likely it will trip again until the air flow issue is corrected. The limit switch tripping is only an indication of another, bigger problem. 

hey, one more doesn't hurt. :laughing:


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## MaximYuryev (Dec 24, 2011)

No, the furnace is totally off when the switch is off. 
I didnt notice any safety switch, there is this cap looking thing. (in one of the pictures)

I did not check a limit stitch?


http://imageshack.us/photo/my-images/824/20111223183907.jpg/
http://imageshack.us/photo/my-images/831/20111223184006.jpg/

http://imageshack.us/photo/my-images/40/20111223184021.jpg/
http://imageshack.us/photo/my-images/192/20111223184035.jpg/

Thank you Guys!


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## yuri (Nov 29, 2008)

bryant/payne/carrier are virtually identical and owned by carrier. he would not have heat if the limit is open and it should show the appropriate error code which he needs to let us know if that is happening. if it is weak and fluttering or intermittent then he could have heat and then it sticks open and keeps the fan running. usually those controls from been ridden/excessively cycled can do that as well. some of the descriptions of these problems lately can be a bit vague or misleading but we do the best we can.


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## yuri (Nov 29, 2008)

the limit control is HARD to see and get at with that unit but it definitely is there behind the white intake piping and looks like the pic I gave you earlier.


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## ben's plumbing (Oct 6, 2011)

yuri said:


> bryant/payne/carrier are virtually identical and owned by carrier. he would not have heat if the limit is open and it should show the appropriate error code which he needs to let us know if that is happening. if it is weak and fluttering or intermittent then he could have heat and then it sticks open and keeps the fan running. usually those controls from been ridden/excessively cycled can do that as well. some of the descriptions of these problems lately can be a bit vague or misleading but we do the best we can.


thanks that what i thought i agree seems vague about some things going on and don't make sense...like you said we'll do the best we can..ben


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## yuri (Nov 29, 2008)

they try but one of them was checking for voltages at the pressure switch while doing the self test on those boards and that never works, he mentioned it later and it made sense to me. self test on carrier/bryant/paynes just energizes the components one at a time to show U if they work but does NOT follow the ignition sequence.


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## Doc Holliday (Mar 12, 2011)




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## ben's plumbing (Oct 6, 2011)

looking at your pictures that gas line is not up to code ....flex is not allowed inside furnace ....needs to be piped to side dirt leg installed then flex the stainless steel kind......getting back to furnace....everything posted seems to lead me to think something is up with control board... if limit is open then furnace would not heat....you said you turn on switch to heat house then turn it off......can't be if limit is open....must be board problem...


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## MaximYuryev (Dec 24, 2011)

http://www.youtube.com/watch?v=F-eRJh3bA2c&feature=youtu.be

heres a link to the video I made, to show you guys better. 

after the burner is on, the led is just constantly on. stops blinking.


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## MaximYuryev (Dec 24, 2011)

Video will finish uploading soon.

The control board is brand new. Just installed couple hours ago.


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## Doc Holliday (Mar 12, 2011)

Get you some gator clip jumper wires. Find each limit switch individually and bypass it. You simply pull off the two wires on the limit, one limit at a time so you can find the problem child if indeed this is the problem, and connect the wires, bypassing the limit.

Bypass one limit, turn heat on. If furnace functions normally when one limit is bypassed then you know it was the limit. If it doesn't, move on to the the next limit. 

If you had a meter it would be easier so we could tell if the limit had continuity or not. 

If I'm not mistaken the draft inducer may have a limit on it as well.


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## yuri (Nov 29, 2008)

OK, lets start in the beginning.

1) Do you have heat, does the burner fire up and heat the house?

2) After the burner shuts off when the thermostat is satisfied does the fan keep running?

There should be 1 LED on the circuit board which gives you error codes. Read this label carefully as the short flashes can be mixed up for long ones and then you read the wrong code. If there is no problem then the led will just shine.

Ben and Doc you may want to cut/copy and paste this chart for future reference and most carriers use it except for the ecm/variable speed units.


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## ben's plumbing (Oct 6, 2011)

Iam i missing something here....the unit heats up.....if that is the case all safty switches and limit switches are good???????????


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## MaximYuryev (Dec 24, 2011)

video up. shows led code.. right after flame lights the led is solid on. 
when the house is heated up, the thermostat tells the flame to shut off, 
the flame stops. and the fan stays on and blows cold air... if left this way, when the house cools down a bit, the stat will signal for heat, and it takes a bit to spin up, but the flame will ignite again and heat will go...


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## yuri (Nov 29, 2008)

OK, I have to go out soon but I will tell you a few points.

1) You should not run that furnace with the board dangling as it may not be grounded properly and could now be damaged.

2) You are getting a code 12 at startup which is normal

3) When the heat cycle ends naturally or just drop the tstat 1 deg below the house temp see if there are any error codes flashing. If the limit control is weak and opening it should give the code off the chart. That chart should be on the back of the front door or the lower door also. If the limit opens then the furnace thinks it is overheated and turns on the fan to "cool" itself off and won't stop until the control resets itself.

4) Make sure there is NO 24 volts at the Y to C terminal when the heat ends or when it is on or you may be energizing the ac and ac fan speed and have a short in the wiring or crossed wires. the ac won't run in cold weather due to the outside low ambiant control but you could still energize Y and turn on the fan as G is not needed on modern boards for the ac fan speed.

Back tomorrow

Yuri


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## Doc Holliday (Mar 12, 2011)

I'm wondering if he's letting it stay on past the 90 second blower on delay on initial power up due to the fact that all Carrier furnaces (Bryant is Carrier) do that.

OP, put the doors back on or hold the door switch closed and let it run on heat. The control board recognizes that power to the unit was cut off so first it runs blower only on for 90 seconds, regardless of heating or cooling call, and then goes into heating mode if it's on call for heat to begin with. The blower will stop and then the heat sequence will start but the furnace has to maintain power to it thoughout the first blower on 90 second (flash code 12) entire cycle.

Are you letting it run past the first 90 seconds, past that cycle? If there's a problem after it will show in a flash code, a different one.


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## Doc Holliday (Mar 12, 2011)

Okay, I finally watched vid. What's the problem, it fired up? And did anyone else notice the ground wire terminating to the gas line? Holy hell.


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## harleyrider (Feb 20, 2007)

you have a bad primary or secondary heat exchanger.


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## qbert (Mar 23, 2009)

Did you install a new tstat ? is it configure for nat gas or electric if you did. if ok i would look into my low voltage wiring.


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## MaximYuryev (Dec 24, 2011)

hey guys, so I checked if it will throw a code after stat is statisfied . I recorded another video. Sometimes it does throw the code, and sometimes it doesnt. 
http://youtu.be/j9vDxAomYt4

heres some more pics. I Found the High limit switch, Im guessing thats what bad? Do I need a new one or can I reset this one? 

http://imageshack.us/photo/my-images/198/20111226171512.jpg/
http://imageshack.us/photo/my-images/833/20111226164413.jpg/
http://imageshack.us/photo/my-images/221/20111226164433.jpg/


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## harleyrider (Feb 20, 2007)

1 st off......has the pressure switch been replaced? they had a voluntary recall on those switches. 2 nd......if you call for heat, then let the furnace fire up and then shut it down before the primary blower comes on............as you did in that video, of course its going to blow the limit. 3 rd......you need to have the heat exchanger checked, they are having a 75% + failure rate on them.


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## Doc Holliday (Mar 12, 2011)

fourth, there is more than just one limit switch on any furnace.


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## harleyrider (Feb 20, 2007)

Doc Holliday said:


> fourth, there is more than just one limit switch on any furnace.


that furnace has 1 limit and two roll outs ....obviously they are all in series with each other


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## MaximYuryev (Dec 24, 2011)

So Guys I only found 2 limit switches, here are the pictures. I bypassed them one at a time, and there was no difference made.... anything else I could try? are there anymore that are hideing... I looked everywhere Cant find any more switches.. 

If I have a bad heat exchanger If I bypass the limit switch it blower should funtion properly right?

http://imageshack.us/photo/my-images/402/20111230203800.jpg/

http://imageshack.us/photo/my-images/850/20111230203831.jpg/


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## MaximYuryev (Dec 24, 2011)

Doc Holliday said:


> Get you some gator clip jumper wires. Find each limit switch individually and bypass it. You simply pull off the two wires on the limit, one limit at a time so you can find the problem child if indeed this is the problem, and connect the wires, bypassing the limit.
> 
> Bypass one limit, turn heat on. If furnace functions normally when one limit is bypassed then you know it was the limit. If it doesn't, move on to the the next limit.
> 
> ...


 
I didnt see a limit on there... There is a small black box with two wires connecting. I thought It was a relay, could this be a limit?

http://imageshack.us/photo/my-images/805/20111223184035.jpg/




harleyrider said:


> that furnace has 1 limit and two roll outs ....obviously they are all in series with each other


 
Where is the other roll out?

The pressure switch is operating properly. Not sure if previous owner had it replaced. 


Thank you guys so much!


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## harleyrider (Feb 20, 2007)

MaximYuryev said:


> I didnt see a limit on there... There is a small black box with two wires connecting. I thought It was a relay, could this be a limit?
> 
> http://imageshack.us/photo/my-images/805/20111223184035.jpg/
> 
> ...


how do you know that the heat exchanger is NOT bad and the pressure switch IS good? You need a manometer to check both.


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## harleyrider (Feb 20, 2007)

MaximYuryev said:


> I didnt see a limit on there... There is a small black box with two wires connecting. I thought It was a relay, could this be a limit?
> 
> http://imageshack.us/photo/my-images/805/20111223184035.jpg/
> 
> ...


 you only have 1 roll out due to the furnace being so small in BTU......and that picture is of a capacitor for the ind.motor......do not by pass it


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## partwerks (Sep 25, 2011)

*Fan relay*

I have a burned spot on the circuit board and my electrician jumped a wire over to it, but he said that if that don't work, then the fan relay's contact points probably took a dump when it all went down, and that if I can come up with a fan relay, I wold be back in business or a circuit for for model HK42FZ011


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## biggles (Jan 1, 2008)

remove the stat off the subbase that toggle ON by the furnace.question? that white wire you pulled off the board was it connected to G there?pu the white wire back fan is running:whistling2: pull the R wire off the board that goes up to the stat subbase? if the fan goes off the run up to the stat is touching on R (red) to G (green)


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