ccmrehab

If I could get some help that would be great.

Here is the problem: I have a Bryant 383Kav Upflow and it isn't working properly. It cycles thru and ignites but only stays on for approx 6 minutes. After shutting down the led light flashes a code of #33 which basically says it could be multiple things. Here is the list:

1. Blower motor failure
2. motor start capacitor
3. open flame rollout switch, manual reset
4. inadequate combusion air supply (flame rollout switch only)
5. Dirty Filter
6. Defective limit switch or connections
7. Loose Blower wheel

The blower motor works, I change my furnace filter at least once a month if not more, I had a guy come out and replace the limit switch last year. Could it be that is the problem again. I am not sure how to check for numbers 2, 3, 4

This is also what i do know. When the furnace is on you can feel the heat blowing from the vents very well downstairs but not upstairs at all. The furnace is located in our laundry room which happens to be upstairs so you would think you would be able to feel heat blowing from the upstairs vents more so than downstairs. Also It kicks on stays on for six minutes like I said and then shuts down and displays the red led code for about 1.5 minutes and then kicks back on. I got up into the attic and checked to make sure all the supplies are hooked to the trunk and that is ok.

Well I hope I gave enough info to describe my problem and hopefully I can get some insight as to what it is or how to fix it. I also would like to know if it is the limit switch If this is something I can buy my self or do I need to have an HVAC guy come out again.

Thanks in advance for any help I recieve

HeatPro

It is a somewhat popular idea among novices that the cure for a limit switch shutdown is to replace a limit switch; however, it is a safety warning device. A similar 'cure' would be to shut off the smoke alarm if there were smoke.

In other words, it isn't a matter of having someone teach you all the things that can go wrong by an unsupervised hands-on correspondence course in furnace maintenance repair. There is no way to 'tell me all you know in five minutes.' (because that is all it took to learn the trade.)

If you've opened up all the registers, and removed all obstructions to air flow, and the problem continues, call a pro now to stop the problem.

ccmrehab

Well I was hoping I could get some kind of advice from someone. I am not sure if Heatpro is being somewhat sarcastic or what. I have a hard time reading between the lines on these forums. Anyways I was hoping I could get some heat for my family seeing how it's literally 5 degrees outside. I am sure I will have to call a pro, but if its just a part that I can go get then thats what I will do.

Furthermore, I was hoping to get some type of advice like, "did you check this, or is this happening" I am not trying to gain advice so that I can go out an start charging people money for a handyman service that can fix furnaces.

And If i didnt give enough info that is fine as well, I can explain anything if asked. If no-one has any advice for me as well, then thats ok too, the problem will get fixed.

GreaseMonkey

If all ducts look fine on the outside you could have an air restriction on the inside of the plenum. Sometimes the insulation lining in the supply plenum will d-laminate, and flap over and restrict a supply trunk. Need to either cut your plenum open to take a look or remove a duct right off the plenum and take a looksi.

ccmrehab

GreaseMonkey: "If all ducts look fine on the outside you could have an air restriction on the inside of the plenum. Sometimes the insulation lining in the supply plenum will d-laminate, and flap over and restrict a supply trunk. Need to either cut your plenum open to take a look or remove a duct right off the plenum and take a looksi."

I was actually heading in that direction last night. I opened up the plenum and could not see anything that could possibly be obstructing it. Today I think I am goin to remove some ducts and see if can see whats going on. I appreciate the advice.

If there is an obstruction somewhere is it ok to assume that it wont be out of reach. Not sure on that, I cant imagine how I could have an obstruction somewhere deep.

HeatPro

IT is difficult for us to know if you are kidding about this as well. Someone who tells us that a pro replaced a limit switch because it was working is somewhat unbelievable. Seems that when you need the heat the most, and the furnace runs long enough to provide that heat, it goes off on high limit due to inadequate air flow or too high a burner setting.

However if a pro tells you
believe it and act accordingly.

ccmrehab

Heatpro
I appreciate your line of thinking, i really do. I am not kidding in no way shape or form when I tell you that exactly on Dec. 31st our heat went out and we paid a guy from the yellow pages to come out and fix it. He was in and out with in 20 minutes and had stated that it was the limit switch.

So anyways, here is the deal for me if you care to know. I will make one last attempt to fix it today. Thank god we bought a model home that has two gas fireplaces that heat the downstairs somewhat ok. After this I will take your advice and CALL a PRO.

Do you travel!!!!

HeatPro

I do travel; but my usual direction is to Las Vegas. I do hear that Indiana does have some casinos, though.

The reason you'll call the pro is to get him to use thermometers to check the bonnet and duct temperatures to find if they are exceeding the rise of the air temperature through the furnace from return to supply main. This will tell him if the fan is pushing enough air against the ductwork, if the fan speed has to be raised, if the fan is strong enough to move enough air to prevent overheating against ducts that are too small, if the gas pressure has risen to make the input too large, and other things. He won't be a pro if he doesn't bring in instruments to do the job.