Hi, I've got a ten year old bryant plus 80 furnace that, reads a code 33 while it cools, it is a solid while fired up but it constantly cycles. I've checed the condenser it looks clean on both top and bottom , filter is clean, all returns are open. Would making anouther return somewhere in the house help. When fired up it will cycle after about 3-4 minutes. Also we did open up 3 supplies for varios rooms (new b-room, and converted a 3 season rm) over the past few years. I don't know if that could be a cause of this problem

https://www.askmehelpdesk.com/heatin...-a-269417.html

33 LIMIT CIRCUIT FAULT - Indicates a limit, draft safeguard, flame rollout, or blocked vent
switch (if used) is open. Blower will run for 4 minutes or until open switch remakes
whichever is longer. If open longer than 3 minutes, code changes to lockout #13.
If open less than 3 minutes status code #33 continues to flash until blower shuts off.
Flame rollout switch and BVSS require manual reset. Check for: - Restricted vent
- Proper vent sizing - Loose blower wheel. - Excessive wind
- Dirty filter or restricted duct system.
- Defective blower motor or capacitor. - Defective switch or connections.

- Inadequate combustion air supply (Flame Roll-out Switch open

I am sure Jay and everyone thanks you for the time you and other experts put in to help.

Often a poster gets an answer based on the very limited info they provide.

No one can fully find problems wtihout a complete check physcially of a system, and even then hidden issues can exist.

And of course one understands when asking questions here, it may take several days for others to join in and help, And of coure when a OP is not thankful or trying to work with a person helping them often others may be less willing to try and help.

From Dec 10th to Jan 23 is a long time to be without heat. Ya just cannot make everyone happy. LOL

We had heat it was cycling on and off, needed more air like I thought and asked!

Without knowing how much you had to start with I would have no idea what you needed. Usually when a furnace is installed by a HVAC company they do a manual J for size of equipment and a manual D for all the duct sizes both supply and return. When that info is not available all else is guess work which I do not do guess work. Never have and never will since to many times damage can be done to the equipment without the proper air flow. Heat exchangers go bad in furnaces and compressors go out in A/C or heat pumps so I cannot afford to guess. We never have any idea of what a person has in there home unless they tell us the exactly what they have to start with and most of the folks that post here have no idea of what they have or what they really need.

Glad you got it going for now and if you do not have a CO monitor in your home I suggest you get one to be on the safe side.

Sure do, got kids take all the precautions

Take the blower door off and tape the door switch closed with the blower door off will the system run? (trying to finde out if the air flow restriction is return or supply or just a bad main limit).

T-Top - I know this is an old topic, but I am interested in what you requested of the original poster. I am running into the same problem he had and the only way I found to keep the heat ignited was to leave the blower door off, yet even though it was running, the house struggled to get warm (ie. Thermostat was set to 72, with the door off it would stay around 65. When I put the door back on the problem would bounce back and forth (heat / no heat but fan kept running resulting in cold air). Fan is set to 'Auto' at thermostat. I have taken out the flame sensor (?? ) and cleaned with brillo pad and replaced did not seem to make a difference still have the same problem. When the heat was on (flames active) I tested all of the switches for voltage and all read fine. Please tell me what you think since the system seems to run fine with door off, yet does not heat completely, which is logical since the cold air in the garage is being sucked in. My main concerns are of course the temp since I have a 5 & 4 year old, second the thought of next months Gas and Electric bill since it seems the system is running constantly. Any help you could provide would be great.

Thanks,

Jason