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pr_capone
01-18-2012, 10:58 PM
I've got a Coleman furnace that has decided that it will only blow cold air. The house is at 68 degrees.

Any ideas? Is there a pilot like on a water heater that I can check for? It is gas.

Phobia
01-18-2012, 11:02 PM
Any ideas? Is there a pilot like on a water heater that I can check for? It is gas.

I sure hope so.

Brock
01-18-2012, 11:02 PM
how old is it

pr_capone
01-18-2012, 11:03 PM
5 years tops...

Coleman Model # FC30A3XN1A

Not finding anything on the net right off the bat.

Phobia
01-18-2012, 11:04 PM
When is the last time you had it serviced?

Got any kids in the area who are big enough to throw a valve?

MIAdragon
01-18-2012, 11:04 PM
68 is perfect, thats around what my house it set at.

Phobia
01-18-2012, 11:05 PM
Sure you're not empty? http://lh4.googleusercontent.com/public/vDrRQpNpJCnUAY09Ft9VXbBeO7MDpXCELqPIjvsAC3IjCuKQ6X55wcnOtFPKp1mLToTmUH_01_lbvODYYUnJbNmdYkHtSwV17-nIAYkvzSS3lqrq-Mf418BZaWLQ45QzMl8RD-3kz2nPro2ct5bY9QaHFk5YNMlQ4HDo0ppjP6s

pr_capone
01-18-2012, 11:05 PM
When is the last time you had it serviced?

Got any kids in the area who are big enough to throw a valve?

Nope... mostly older neighborhood.

Honestly, never have had it serviced. Wasn't aware that it needed a yearly checkup.

Chief Roundup
01-18-2012, 11:06 PM
Check the breaker that it is on first. Don't be afraid to turn it off and back on just to make sure.

Depends it could have a standing pilot, it could have a hot surface ignitor, or a spark ignitor.
How old is the unit? Is it an 80% or a 90% gas furnace? If you don't know how to tell one will have a metal exhaust the other will have PVC for the exhaust.

pr_capone
01-18-2012, 11:06 PM
68 is perfect, thats around what my house it set at.

I like to walk around naked though. My dangle is looking a bit weak. Need that extra 3 degrees for optimum hang.

MIAdragon
01-18-2012, 11:09 PM
I like to walk around naked though. My dangle is looking a bit weak. Need that extra 3 degrees for optimum hang.

LMAO

pr_capone
01-18-2012, 11:10 PM
Check the breaker that it is on first. Don't be afraid to turn it off and back on just to make sure.

Depends it could have a standing pilot, it could have a hot surface ignitor, or a spark ignitor.
How old is the unit? Is it an 80% or a 90% gas furnace? If you don't know how to tell one will have a metal exhaust the other will have PVC for the exhaust.

If I go to the thermostat, I can turn the fan on and it blows so I'm guessing that whatever electrical unit in there moves the air is working, IE it has electricity. Am I off there?

The unit is about 5 years old or so. The exhaust looks metal (if on top) though I see some PVC heading to the crawl space towards the bottom.

Chief Roundup
01-18-2012, 11:15 PM
5 years tops...

Coleman Model # FC30A3XN1A

Not finding anything on the net right off the bat.

That number references the A/C coil.
There will be another I.D. plate. It might be outside of the cabinet on the side or inside the door on one side or the other.

Chief Roundup
01-18-2012, 11:18 PM
If I go to the thermostat, I can turn the fan on and it blows so I'm guessing that whatever electrical unit in there moves the air is working, IE it has electricity. Am I off there?

The unit is about 5 years old or so. The exhaust looks metal (if on top) though I see some PVC heading to the crawl space towards the bottom.

Yeah if the blower runs when you turn it on it has power. If it has the metal exhaust then it will be an 80%. The PVC at the bottum is the drain for the A/C coil.

pr_capone
01-18-2012, 11:19 PM
That number references the A/C coil.
There will be another I.D. plate. It might be outside of the cabinet on the side or inside the door on one side or the other.

Ok... don't have a model number but I have more information. Looked at the inside of the door there and there is a fault code.

I see a red light flashing 4 times which indicates "limit switch open"

what does that mean? lol

Boise_Chief
01-18-2012, 11:22 PM
It's kind of tough to tell you from 500 miles away but I'm guessing it's one of several possible things.

Take your doors off the front, there will be a switch that you need to tape down for it to run. Turn off your thermostat for 10 seconds or so and then turn it back on. go to your furnace and let me know what happens. do you see a glow after about 20 secs and does it try to light. Is the combustion motor running, it's the little motor behind the cover you will be looking at the end of it.

It's probably one of these things:
Bad transformer 110v - 24v
Combustion motor not running
thermostat bad ( batteries, not prog correctly likely)
bad igniter or flame sensor

Chief Roundup
01-18-2012, 11:27 PM
Man this could be a lot of different things. If you have never had it serviced the burners could need to be cleaned which can cause the flame to roll out of the heat exchanger and hit a safety switch.

When you make the thermostat call for heat after it has been off does the inducing motor run?

Does it have an electronics control board with a light on it? If there is and it is blinking count the flashes. The pauses might seperate 2 numbers. There should be a label on the door that will tell you what the flashes mean.

Boise_Chief
01-18-2012, 11:28 PM
hehe just so your code for the limit switch.
Change your filters...
there is a sensor that goes into the airbox probably on the right side should have 2 wires going into it. there may be a little reset button to hit to reset it. your furnace can't breathe correctly. It is not getting enough airflow or it is over heating. You may also have a small rubber hose going to an airpot pull off the hose and us a little bit of wire like a paperclip and clear the rust that is blocking it inside the limit switch.
Should be one of those.

Chief Roundup
01-18-2012, 11:30 PM
Ok... don't have a model number but I have more information. Looked at the inside of the door there and there is a fault code.

I see a red light flashing 4 times which indicates "limit switch open"

what does that mean? lol

A Limit Switch is a safety mechanism. You should have a professional come look at it in person.
Limit switch tells me that you have had the flame roll out of the heat exchanger or the heat exchanger is getting to hot.

Phobia
01-18-2012, 11:32 PM
I think your furnace is being choked for air. You may need to build a little air ramp so air can get into your furnace. Do you have any kind of experience building ramps?

pr_capone
01-18-2012, 11:35 PM
Wierd.

Ok, so I opened up the furnace and it has a button on the front. I push and hold the button and everything fired no problem. I can see the blower turn and I can see 4 gas jets kick on and turn to flame. Seems like the furnace itself is ok...

I replaced the batteries on the thermostat but now I can't get the fan to kick over from the thermostat.

Chief Roundup
01-18-2012, 11:36 PM
hehe just so your code for the limit switch.
Change your filters...
there is a sensor that goes into the airbox probably on the right side should have 2 wires going into it. there may be a little reset button to hit to reset it. your furnace can't breathe correctly. It is not getting enough airflow or it is over heating. You may also have a small rubber hose going to an airpot pull off the hose and us a little bit of wire like a paperclip and clear the rust that is blocking it inside the limit switch.
Should be one of those.

Yeah if it is a high limit you could have a restriction and you should change your filters every month on average.

pr_capone
01-18-2012, 11:36 PM
I think your furnace is being choked for air. You may need to build a little air ramp so air can get into your furnace. Do you have any kind of experience building ramps?

I need you to ban yourself from this thread now. LMAO

Boise_Chief
01-18-2012, 11:39 PM
There are 2 limit switches on a furnace. 90 plus percent of the time it is dirty filters not allowing enough air flow or rust inside the switch from condensation. On a 5 year old furnace I would be shocked to have a problem with the heat exchanger. take a pic of the front without the covers on.

Chief Roundup
01-18-2012, 11:39 PM
Wierd.

Ok, so I opened up the furnace and it has a button on the front. I push and hold the button and everything fired no problem. I can see the blower turn and I can see 4 gas jets kick on and turn to flame. Seems like the furnace itself is ok...

I replaced the batteries on the thermostat but now I can't get the fan to kick over from the thermostat.

I know you will but be sure to watch it and if it does it again do not reset it because that indicate you have a problem. Then call a technician.

Boise_Chief
01-18-2012, 11:42 PM
taking the cover off cut power to the board and reset it. Is your cover on now? don't forget to check the filters it will probably happen again unless you figure out what was reducing the airflow problem.

pr_capone
01-18-2012, 11:43 PM
Tell you what... I guess these things are like computers. Opened the lid, pressed the last error code button and nothing showed up. Changed the filter and put the lid back on and now everything if firing on all cylinders.

Odd but I'll take it. IF it goes down again I'll be sure to call an hvac tho. The assist is much appreciated for this (less than)HandyMan.

Chocolate Hog
01-18-2012, 11:47 PM
Ask Bugeater he knows his shit.

Boise_Chief
01-18-2012, 11:56 PM
Another thing that could effect it is if you have shut down the vents in multiple rooms.
Good luck.

mikeyis4dcats.
01-19-2012, 05:12 PM
bad filter...it worked with the panel off because it was pulling air direct from the room