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jlaudz · Nov 5, 2008, 04:18 PM

Hi all,

I have this Carrier HVAC but its not blowing any heat at all. Cooling is fine. The burner and fan start as I can hear the fan and flame starts but it cuts off.

I turned off the circuit breaker to reset it and try to re-start. It did re-start, blow air, starts the furnace but it shutdown again (even it is set to highest temperature possible) after 1 minute of so and won't start until it is resetted. Also a red LED label W1 is lit when it shutsdown. Damper 1,2 & 3 is also lit up before it shutdown. I have switch the control from upper and lower level contolling only upper level but it still didn't work.

The furnace is on the attic arounf 65F outside temp.

Any idea?? I'm not so familiar with HVAC but I can read schematics. What do you think is the cause of heat.

Thanks,

John

mygirlsdad77 · Nov 5, 2008, 05:00 PM

Start with the basics. Clean flame senser. If it is a 90+ eff, check for clogged drain lines. Check these, and get back to us. Most carriers will run the circulation fan motor for one minute( if powered up while there is a call for heat) before it will start the draft inducer( beginning the actual call for heat)

jlaudz · Nov 8, 2008, 12:57 PM

Originally Posted by mygirlsdad77

start with the basics. Clean flame senser. If it is a 90+ eff, check for clogged drain lines. Check these, and get back to us. Most carriers will run the circulation fan motor for one minute( if powered up while there is a call for heat) before it will start the draft inducer( beginning the actual call for heat)

The system is pretty new actually (< 3yrs) but I check it anyway. It is clean so far. I also notice after it shuts down a 1 short blink then 4 successive same interval blink then off for a second or two then repeat process... 1 short blink, then 4 .

It also got check/service last year for same problem ( I think), since this happens during same time last year. (first time turning heater on)

Any recommendation? Thank you in advance.

mygirlsdad77 · Nov 9, 2008, 04:22 PM

The blinks are a diagnostic code. There should be a area inside the blower door or somewhere on the furnace that will tell you what the blinks mean. I don't remember the codes for carrier. Almost every brand of furnace uses diffent codes. Please let me know what your code is saying. You may have to call for onsite help. If you do, watch what they do and ask questions. Just let them know that you would like to be able to fix simple problems on the furnace. But it may be something that you need professional help with.

Lets just start with the blinking code.

jlaudz · Nov 10, 2008, 11:48 AM

Error code 14. I also read the install manual, and follow the schematic and do some diagnostic. It seems like when the cpu is not detecting the flame when it do its test, so it shuts down the gas valve 2 secs after it turns off the flame starter.

I measured resistance of the flame detector and it measures infinity (open circuit) between the connector and gnd (chassis).

How much resistance a typical flame sensor should be? Where can I buy this part? Other than the flame detector, what is the possibility that the board itself is defective?

John

Originally Posted by mygirlsdad77

the blinks are a diagnostic code. There should be a area inside the blower door or somewhere on the furnace that will tell you what the blinks mean. I dont remember the codes for carrier. Almost every brand of furnace uses diffent codes. Please let me know what your code is saying. You may have to call for onsite help. If you do, watch what they do and ask questions. Just let them know that you would like to be able to fix simple problems on the furnace. But it may be something that you need professional help with.

Lets just start with the blinking code.

mygirlsdad77 · Nov 10, 2008, 05:37 PM

I know you said you cleaned the furnace, but have you actually physically cleaned the flame senser? Very seldom do you actually have to replace a flame senser, 99.9% of the time cleaning it with sandcloth, sandpaper, steelwool or any abbrasive cloth will solve the flame senser problem. This is a great place to start. It is also possible that your baord is bad, but would definitely check into some other things, (flame senser first), before spending the money on a board. Do you know where the flame senser is located on your furnace? It will be somewhere directly in the flame, on one side of the burner or the other. Its should be a single rod. Don't confuse it with a glow plug or spark igniter. There will only be one wire going to it. If you have a sealed combustion unit, it may be in a group with your ignition. Let me know what you see.

jlaudz · Nov 11, 2008, 08:32 AM

Originally Posted by mygirlsdad77

i know you said you cleaned the furnace, but have you actually physically cleaned the flame senser? Very seldom do you actually have to replace a flame senser, 99.9% of the time cleaning it with sandcloth, sandpaper, steelwool or any abbrasive cloth will solve the flame senser problem. this is a great place to start. It is also possible that your baord is bad, but would definately check into some other things, (flame senser first), before spending the money on a board. Do you know where the flame senser is located on your furnace? It will be somewhere directly in the flame, on one side of the burner or the other. Its should be a single rod. Dont confuse it with a glow plug or spark igniter. There will only be one wire going to it. If you have a sealed combustion unit, it may be in a group with your ignition. Let me know what you see.

Hi, I've re-opened the furnace and clean the sensor with steel wool. It shiny now but the furnace still doesn't work. I also notice that the flame sensor is not directly in the middle of the flame, its on the side, but it still touches the flame. Will this cause any problem? Can I bent the sensor without damaging it?

If indeed the this is a sensor problem, do you know a place to get replacement? Sears maybe? Any online store that you use?

Other then the sensor and the main PCB, what other possibilities the problem could be?

Thanks,

J

jlaudz · Nov 12, 2008, 08:12 PM

HI, I got a new flame sensor from my local appliance store. Installed it today and this baby start blowing flame.

Thank you so much for your help. I would have not done this without your guidance.

Thanks again

J

mygirlsdad77 · Nov 13, 2008, 04:47 PM

Just glad you got it fixed. Take care