Blower in attic & AC unit outside continuously run
My AC started to act up a couple of weeks ago. When the unit turns on to cool the house, I would hear the blower motor located in the attic engage, hummm and then shut itself off. The fan in the attic did not feel stuck when I went up there and manually turned the blades, but it did turn on briefly, worked for a few days before it died completely a week later. I had the existing thermostat replaced with a digital one and it still did the exact same thing. Hummm and shut off. I bought coil cleaner and cleaned the entire attic system to no avail. An AC tech (whom I do not believe to be experienced, but had the unfortunate circumstance to call on) bought a new blower motor, replaced it and now, the blower motor does not stop running AND the AC unit outside is rigged so that the contact on the unit is ALWAYS depressed to keep the unit continuously on. He said he cannot find the problem and since it was 'cool enough' in the house he did not consider it an emergency! He said it should be easy enough for me because, to turn the unit off, I have to go to the main breaker box mounted to the back of the house and flip the AC outside switch. To turn the blower off in the attic, I have to flip the switch that controls that entire circuit, too. I was appalled but could not afford to get ripped off again.
Trouble shooting on my own, I have looked at the thermostat wiring. I have G, Y, W, Rh jumper to Rc. it looks correct, but i can't help but think there must be some wiring problem. Alas, I am but a girl who does not fully understand an HVAC system, but desperately needs to.
Any help?
Trouble shooting on my own, I have looked at the thermostat wiring. I have G, Y, W, Rh jumper to Rc. it looks correct, but i can't help but think there must be some wiring problem. Alas, I am but a girl who does not fully understand an HVAC system, but desperately needs to.
Any help?
Heating & Cooling - Ruud - Matching Split Air Conditioner
Answers & Comments
Sorry to hear about your miss-fortune, you are right it is an wiring problem. Can you turn off the blower with the thermostat (cool-off-heat) or what happens when you switch the fan to (auto or on) When you say the outside unit is "rigged" is it mechanically being jammed or electrically? If its mechanically that should be removed (what a crappy thing to do) other wise it will run continuously as you may already know. That is what it sounds like, you should just be able to shut the entire system down by turning off the switch to the furnace. If it is electrically being held closed, he changed some of the wiring around in the attic unit, you better hope he was lazy and jammed a stick in the contactor in the outside unit or else you may need to learn more about HVAC wiring, none the less I would double check the thermostat wires going to the attic furnace there should be nomenclature on the unit or at least somewhat marked. This was probably disturbed when the new blower was installed, by the way that was your initial problem. Good luck and becarful
Sounds as though you are doing everything possible to keep cool, good job. With out being there this can be difficult to trouble shoot, too many different brands.
Now was the unit operating properly before the blower went out? and yes per your description it sounded as though the blower failed he got this right, yes replacing a blower motor is quite invasive, and some wiring may get disturbed in the process.
I would check the thermostat wiring, if all looks well you may have a bad transformer (your thermostat wiring runs off of this for safety reasons) it should be 24 volts on the output and 120 volts (house power) on the input, and is located in the furnace wiring area where the motherboard is. It may have shorted out, usually not very expensive $30-$50 or there may be a fuse inside somewhere that may have blown that would be the easiest fix.
The power from the furnace(120v) energizes the transformer, the transformer sends 24v to the thermostat, then back to the motherboard in the furnace (handler), the motherboard sends power 120v to the blower, air blows through the ducts and may operate a flow switch or timer (depending on the unit) then the motherboard will send 24v to the coil of the contactor on the outside unit, energizing the contactor, thus sending 220v to the compressor and fan outside. Its really not that confusing :)
If you look inside at the wiring make sure you put the cover back on, or the unit will not work at all, there is a safety switch located near the opening. I don't like the fact that a "pro" stuck a piece of plastic in a 220 volt contactor holding it closed, and then just left you high and dry, but I guess at least it keeps you cool. You may need to acquire a volt meter for some of these tests, and if you are not comfortable doing it... don't do it, you may make the situation worse.
Good luck and be careful
Aug 19, 2009 - Sounds as though you are doing everything possible to keep cool, good job. With out being there this can be difficult to trouble shoot, too many different brands. Now was the unit operating properly before the blower went out? and yes per your description it sounded as though the blower failed he got this right, yes replacing a blower motor is quite invasive, and some wiring may get disturbed in the process. I would check the thermostat wiring, if all looks well you may have a bad transformer (your thermostat wiring runs off of this for safety reasons) it should be 24 volts on the output and 120 volts (house power) on the input, and is located in the furnace wiring area where the motherboard is. It may have shorted out, usually not very expensive $30-$50 or there may be a fuse inside somewhere that may have blown that would be the easiest fix. The power from the furnace(120v) energizes the transformer, the transformer sends 24v to the thermostat, then back to the motherboard in the furnace (handler), the motherboard sends power 120v to the blower, air blows through the ducts and may operate a flow switch or timer (depending on the unit) then the motherboard will send 24v to the coil of the contactor on the outside unit, energizing the contactor, thus sending 220v to the compressor and fan outside. Its really not that confusing :) If you look inside at the wiring make sure you put the cover back on, or the unit will not work at all, there is a safety switch located near the opening. I don't like the fact that a "pro" stuck a piece of plastic in a 220 voltcontactor holding it closed, and then just left you high and dry, but I guess at least it keeps you cool. You may need to acquire a volt meter for some of these tests, and if you are not comfortable doing it... don't do it, you may make the situation worse. Good luck and be careful