Not an HVAC guy by any stretch, but I don't mind trying to figure things out, so here's the story.
My second floor AC stopped working just as the weather got warm here in northern IL. It would run a bit and then shut down before making any difference. No codes showing on the blinking LED from the furnace board. I thought maybe it had something to do with the Amazon thermostat, so I thought I'd replace it with a regular thermostat as a test. Because it used a C-wire adapter, I opened the furnace panel to unhook that, and was greeted by a burny smell. Huh. I remembered smelling that through the vents when the AC came on for the first time this season.
I thought initially it was the control board. I saw a resistor that looked like it was heating up. Tried running the system and yes, the resistor was getting hot. So I thought, well, I don't have to have the board to run the fan. I disconnected the blower motor from the board and rigged up a plug-in power cord to run the fan directly, figuring I could at least bring cool air up from the basement. The blower ran for about 10 minutes and then turned itself off, same burny smell. Aha! It's not the board, it's the blower motor. Some sort of internal fault, it's heating up inside and tripping its thermal protection.
So I sourced a blower motor from Amazon. Was supposed to be here Wednesday, then late Tuesday it got unexpectedly updated to Friday (today). So I ordered another motor, not an exact match (three speeds instead of four, different wiring color codes), to arrive earlier. It got here yesterday, but as it happens the nights have been cool, so I decided to wait for the first motor (the exact part) to get here. Was supposed to be here today. At 8am it left Hebron, KY and I don't think it's going to be here on time.
In the meantime, I pulled new 18/5 thermostat wire up to the second floor thermostat (builder put it in conduit from the basement to the attic, loose in the attic, and conduit from attic to thermostat location, so it was fairly easy), so I can disconnect that C-wire adapter. Which motor I install is going to depend on how much more delay in the delivery. I also ordered a new control board because that hot resistor worries me, but I haven't decided whether to install it immediately or wait for the existing one to fail.
My second floor AC stopped working just as the weather got warm here in northern IL. It would run a bit and then shut down before making any difference. No codes showing on the blinking LED from the furnace board. I thought maybe it had something to do with the Amazon thermostat, so I thought I'd replace it with a regular thermostat as a test. Because it used a C-wire adapter, I opened the furnace panel to unhook that, and was greeted by a burny smell. Huh. I remembered smelling that through the vents when the AC came on for the first time this season.
I thought initially it was the control board. I saw a resistor that looked like it was heating up. Tried running the system and yes, the resistor was getting hot. So I thought, well, I don't have to have the board to run the fan. I disconnected the blower motor from the board and rigged up a plug-in power cord to run the fan directly, figuring I could at least bring cool air up from the basement. The blower ran for about 10 minutes and then turned itself off, same burny smell. Aha! It's not the board, it's the blower motor. Some sort of internal fault, it's heating up inside and tripping its thermal protection.
So I sourced a blower motor from Amazon. Was supposed to be here Wednesday, then late Tuesday it got unexpectedly updated to Friday (today). So I ordered another motor, not an exact match (three speeds instead of four, different wiring color codes), to arrive earlier. It got here yesterday, but as it happens the nights have been cool, so I decided to wait for the first motor (the exact part) to get here. Was supposed to be here today. At 8am it left Hebron, KY and I don't think it's going to be here on time.
In the meantime, I pulled new 18/5 thermostat wire up to the second floor thermostat (builder put it in conduit from the basement to the attic, loose in the attic, and conduit from attic to thermostat location, so it was fairly easy), so I can disconnect that C-wire adapter. Which motor I install is going to depend on how much more delay in the delivery. I also ordered a new control board because that hot resistor worries me, but I haven't decided whether to install it immediately or wait for the existing one to fail.