Home ac on the fritz again.......

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3,872
Location
southern mo
So it was working fine then I noticed blower wasn't blowing and outside unit wasn't on. So I check breakers and fuses all are fine bypass thermostat and nothing no lights on the board either. I'm at a loss.... 3rd time In 2 months that it's messed up. Any idea what's wrong ? And when do you throw in the towel?
 
Messages
410
Location
NC/SC
Mine quit on me a few weeks back and I found the float switch on the condensation catch pan had triggered due to a clogged drain line. Just one place to look
 
Messages
15,879
Location
NE,Ohio
Originally Posted By: ram_man
The unit is a ruud silhouette 2
Thats the furnace.. whats the ac unit? how old is the unit (both furnace and ac) did you ever replace the thermostat you were complaining about in the other post?
 
Messages
357
Location
South Florida
As mentioned above , the float switch would be a great place to start. Often times the transformer is protected by a 3 or 5 amp fuse, see if this has blown, if it's blown or your transformer blew again you probably have a short in your control wiring. If this is the case it's certainly worth repairing, as the transformer is one of the least expensive parts in your system.
 

ram_man

Thread starter
Messages
3,872
Location
southern mo
I don't think it has a float switch. ...If it does where and how do I check it I am certainly not a pro. Where would this said fuse be? I have a round fuse on the wall that is good but I believe that fuse is for the whole unit.
 
Messages
2,191
Location
VA
I'm by no means an HVAC mechanic, but if it were mine and both the blower and outdoor unit were not running I would be looking at the thermostat. Beacuse it seems like if the thermostat were working properly and switching the unit on, one or the other would be working. Again, not a mechanic, just intuition.
 

ram_man

Thread starter
Messages
3,872
Location
southern mo
I bypassed the thermostat to see if I could get it to run but nothing. That is what I was hoping it was. Wish full thinking I suppose.
 
Messages
7,779
Location
Oklahoma
Got to be a fuse somewhere. You have brown outs or power fluctuations? Been some storms going through your area lately.
 
Messages
2,100
Location
Easton, PA
Ya the indoor blower and outdoor compressor are independent of each other. They do not know what the other is doing. I see two possible causes. Blown fuse for the 24v transformer or the transformer itself is bad. Bad motherboard on the unit, if it is bad nothing will happen. An easy way to tell is most have a diagnostic LED. If it is on and not blinking at a fast rate then it is a good chance it is ok.
 
Messages
4,837
Location
Central Texas
Power is everything. Low voltage contactors (relays) are used to control high voltage that powers the fans (blowers) and compressor. High voltage AC is stepped down to a lower voltage AC by a transformer and the low voltage AC is used by the thermostat. I'd suggest getting a DVM and begin measuring AC voltages, IF you're comfortable doing so. Both my indoor & outdoor units have schematic diagrams inside. Yours may as well. You've checked fuses & breakers, so the next step is to measure AC voltages at these points. Just keep your hands away from bare wires and only on the test probes.
 
Messages
5,930
Location
DFW
I buy HVAC repair parts for Lennox and I'm here to tell you it can be MANY things to cause such an issue. I am almost to the point where I could diagnose, but you have to be there. Buying parts does not make me an expert. Some of my coworkers only know the parts as SKU numbers. I have an interest in it and previous experience as a facilities manager.
 

ram_man

Thread starter
Messages
3,872
Location
southern mo
I'm not sure if this helps but the contactor outside isn't pulling in if you push it in manually it comes on. My guess is whatever gives or sends power to it isn't doing its job.
 
Messages
1,121
Location
Hawkinsville Ga
The thermostat/circuit is what energizes the contactor.....check for 24v at the contactor when the t/stat is calling for ac. It's either a bad stat or a broken wire (you said you already replaced the transformer). Weed eaters cause their share of problems with wiring at the condensor unit as well as mice/chipmonks. A shorted wire can also kill a transformer. A bad/activated condensate overflow switch will typically cut power to the unit. Does the blower motor run on "manual"? (Fan modes are usually AUTO or ON.
 
Messages
1,121
Location
Hawkinsville Ga
It sounds like you don't have 24v at the thermostat. Do you have a DVM? I would check for 24v at the thermostat (typically probe the red and green wire....I think). If you're good there, then set your t/stat to cool (set the setpoint way low) and check the contactor (the two "side" terminals are usually the coil or 24v side).....be careful in there since there's also 240v and a capacitor that can shock. Does the heat work....blower and furnace? I'm guessing you don't have power at the t/stat though. I hope this helps some.
 
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