My Carrier KFCEH3101C15 air handler/electric furnace stopped working yesterday. It is a 2006 unit but it had been running very smoothly/quietly. I noticed the metal air filters were very dirty so I blew them out and replaced them. I tried to reset the system by turning the thermostat below the air temperature reading then turning off the two circuit breakers on the unit for a minute, turning them back on, then setting the thermostat to about 5 degrees above the air temperature reading. The thermostat then read "Aux Heat" as if it was trying to raise the temp in the house but the air handler never kicked on. I turned the fan switch from auto to "ON" but the fan motor did not work. It appears there is no power to the air handler/furnace. I took the access panel off and exposed the blower motor and a-coil and the blower motor felt warm to the touch. The unit has not worked for 24 hours, so either it is retaining heat or it is getting juice but not working. I can't see an obvious reset button anywhere...does anyone know what might be wrong? Could it have overheated because of the dirty air filters, and if so, why won't it reset or how can I troubleshoot and get it running again? I see a lot of wiring and a circuit board inside of the box but no reset buttons or sliders and no fuses to check except a 5amp fuse on the circuit board that looks like a fuse you would put into the panel of a car. Please help--thanks!
Check fuses first! If yours is the model with a fuse box you will see a flap that pulls down to reveal a block of fuses, the blade fuse you described is part of it too! Are all fuses ok?
Testimonial: "Hi Mike, I don't see a fuse block. It's actually pretty cleabn inside the panel. There are two breakers (accessible through an external window), three temperature limit switches, 1 transformer, 1 circuit board with a single 5amp blade fuse (it's good), and two black boxes with small circuit boards on them. Where should the fuses be?"
For 15- and 20-kW fused models: After installing heater assembly, attach fuse assembly to side of fan coil unit by inserting fuse box tab between insulation and to left side of unit and fan deck.
I think the dirty filters caused overheating and blew either fuses/ circuit breakers or a safety switch! Depending on how your model has been set up these would be accessed through a flap in the main housing! These need to be checked!
Circuit breakers or safety switches should be tripped with possibly a red/black button exposed! Just depress these if seen!
Hi Mikey, I think it must be something else. There are two circuit breakers on the furnace and two on the house's main electrical panel, none of which had been tripped. I reset them just in case but it didn't resolve the issue. I checked all 3 safety (limit) switches with an ohmmeter and they were good (all ohmed at 0.00 with the switches closed--I depressed the 'clicker' switch to open the switch and watched the ohms spike before settling back to 0.00 when I released the clicker on each one). There are no fuses. I could not find a "reset" button anywhere on or inside the unit.
The blower motor "hums" lightly when power is applied through the breakers but the blower isn't running. I can't figure out what's keeping it from running. I can't tell whether the heating coils are coming on--not sure how to check them since I can't see them.
Could it be the blower motor faulty! Since power is getting to it.....but not powering it?
Could be that or the run capacitor, not sure. I found a site with instructions to test both, but the capacitor test requires a multimeter with an "MFD" setting (see here:http://www.hvacpartsoutlet.com/troublesh... but mine does not have that setting and I could not find one that does at Sears, Auto Zone, or Harbor Freight. Do you know of another way to test the capacitor with a very basic multimeter without shocking the shazam out of myself? Also, do you know how to bleed down the residual electricity from a capacitor in case I need to replace it? Lastly, the instructions to test the blower motor were a little lacking/wonky ("The easiest way to check the amperage is with an amp meter on the common wire to the motor. Most motors use multiple speeds and each speed has its own specific wire. Using the common wire for an amperage reading takes out the guess work" http://www.hvacpartsoutlet.com/troublesh...]); I have so many wires I can't figure out which is which...not sure quite how to get started.
Hi Dave, this is going into the expert stages! I admire your willingness to get to the root of this! I would get some assistance from an engineer who would be able to do the required checks! I will have to research some more and get back to you!
You are a good man, Mikey--thanks very much for hanging in there with me.
Thanks Dave! I found an online manual and your model is a 15kw with internal circuit protections by fused circuit, breaker curcuit and breaker. Have you checked these with a meter just to be sure?
I found this video that shows the function of your furnace! It gives a few reasons why the fan would not get power!http://www.repairclinic.com/RepairHelp/H...
There are a few parts that could be an issue but seem to be easily tested!
Thank you, Mikey--I saw that reairclinic post as well--I was able to verify everything except the control board. Where did you find the online manual--can you send me a link? Thanks again for hanging in there with me!
It was an installation manual!http://dms.hvacpartners.com/docs/1009/Pu...
Hi Mikey, the issue is resolved and we're up-and-running again! The root cause turned out to be a bad run capacitor (the one mounted on the blower motor). With the power off, I bled down the stored electricity by I removing the wires from the posts with insulated pliers then held an insulated screwdriver across the two posts. I checked the microfarad reading using a multimeter with an MFD/uf setting and it should have read 10uf (+ or - 5%), but it read 0.L. I removed it and replaced with a new capacitor (Grainger, $10.83), flipped the breakers back on and prayed, hoping the blower motor was not also bad. 30 seconds later, the blower kicked-on and we've been steadily warming for the last several hours. It is a beautiful thing. Glory to God and thank you Mikey for hanging in there with me for the last several days. Happy Thanksgiving and Merry Christmas to you!
Well done Dave, your persistence paid off, Every time the heater warms up you from now on you too will get that glow of satisfaction knowing you were able to fix it. Best wishes.
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SOURCE: My outdoor heat will not
you need to go oside and look for a red reset button on the unit. you tripped the high ressure switch when you let your filter get that dirty. go check on this and when your done if it still is not working then ask me more.
SOURCE: approx 2 years old. quit working during recent
it sounds like the contactor is not pulling in . corrision maybe even a bug could prevent it from pulling.
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