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View Full Version : help me avoid calling an HVAC dude



cycosis
07-05-2016, 11:14 AM
So my HVAC went down the other day. No heat, no A/C. The honeywell sending unit is fine as it is trying to send a signal, but the furnace is not receiving/responding. I know this because I swapped the faceplate/sending unit with another furnace and it responded just fine.

I checked the breakers for the furnace and A/C, nothing was tripped. Turned them all off and then back on. Still nothing.

It did not stop working when the system went to turn on. The system was running AC during a warm day and it just turned off suddenly despite it not reaching the desired cooler temperature.

You will notice the red power LED is not on... thoughts?

http://i897.photobucket.com/albums/ac171/Brennonkaczmarek/furnace_zps0pwx33c5.jpg

revelations
07-05-2016, 11:40 AM
First thing I would do is use a multimeter and check for power at the furnace.

jeffh
07-05-2016, 12:51 PM
While the bottem panel is removed, it trips the safety door switch which shuts the whole furnace down, which subsequently shuts off the red led indicator on the control board. Sooo ensure you hold the switch down before you start diagnosing your issues. Not sure at this point, but hopefully the led will give you a code readout.

thinmyster
07-05-2016, 12:52 PM
Check the filters? I had mine trip cause it couldn't pull the required air

cycosis
07-05-2016, 01:33 PM
Filters are brand new and yeah I have the door sensor depressed to simulate the access hatch being closed :S

jeffh
07-05-2016, 08:25 PM
When you have the door switched pressed, nothing happens at all in regards to your furnace(no lights, no blower, t-stat is calling for heat/cool)? If yes, then I would initially ensure 120vac is getting to your furnace. Look past the breaker if you don't suspect it is faulty.

jeffh
07-05-2016, 08:30 PM
Also, wouldn't hurt to ensure your thermostat wiring is intact, I've heard of the old wire breaking between the stat and furnace.