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        AC Unit Fan Will not Stop Sign In/Join 
        posted
        Hello to All,

        It has been awhile. Hope everyone is doing well and had a nice July 4.

        The ranch AC unit was running fine all Sat night, then turned up the temp at t-stat and the condensing unit went off as usual, but the fan kept blowing. It was in the auto mode, so it should have shut off 1-2 min's after temp was raised.

        I had to go to the eletrical box and flip the breaker. That shut it off. Left it off for 20 min's, then flipped the breakers back on, fan went back on. Flipped then off again and left off for 2-3 hrs...flipped back on, fan back on...

        Went up into attic when blower was going and firmly tapped the AC unit 5-6 times, then the blower went off. I left if off for 2-3 hrs again, then turned the t-stat down until the C-Unit and Blower both kicked-on...they both then cycled normally w both the blower and C-Unit going on and off.

        Is this the fan relay switch? And/or are the contacts getting stuck? This happened about 2 yrs ago too, but when I turned off the Unit via the breaker, the fan stay off when I flipped the breaker back on. I think the contacts are getting worse. Any thoughts?

        If it is the fan relay switch, is this a big thing to change? I recently changed out a capacitor on one of my condensing units and that was a piece of cake. I think this will involve more work.

        THank you very much for your feedback.

        Regards,
        tstex
         
        Posts: 378 | Registered: Jun 23, 2010Reply With QuoteReport This Post
        Picture of Jaybee
        posted Hide Post
        My advice for a problem like this is to just call in your regular H/A service company. While it may turn out to be a simple fix the trouble-shooting process for a DIYer can turn into an expensive parts swap. If it is a simple fix, you are only into basic service call fees and parts costs. If it is more complicated than you probably couldn't fix it anyway.


        Jaybee
         
        Posts: 10500 | Location: Knoxville, Tennessee | Registered: Sep 27, 2003Reply With QuoteReport This Post
        posted Hide Post
        Yeah, there is also peace of mind w that solution too Jaybee.

        The problem is I can only get out there either late Fri or weekends, and then it is hard to schedule the guys to come out on weekends, pay through the no$e.

        I will see what I can do.

        Thank you,
        tstex
         
        Posts: 378 | Registered: Jun 23, 2010Reply With QuoteReport This Post
        posted Hide Post
        Yes there is a relay and yes it could be sticking. But as Jaybee points out it can be expensive swapping parts out on your own.

        You will also likely have trouble getting parts locally. Most parts houses will only sell to the trades. I replaced the motor to my blower a few years back, but had to go on line to get it. Shipping ran almost as much as the motor. I know use an independent HVAC contractor to maintain my equipment. I'm on a service plan with him and he is very prompt when an issue pops up. I get both HVAC units serviced twice a year for about $300 total. He's also very good at keeping my aging units running. Many of my neighbors have replaced their units already mainly because ARS has very good salesman and not so great service guys. My HVAC guy and I will know when it is time to throw in the towel and replace the units.


        General Disclaimer

        Any advice given here is general in nature and is not necessarily valid for your given area. If in doubt check with your local codes enforcement department for what is required when doing electrical, plumbing or structural work on your house. Permits may or may not be required in your area and home owners may not be able to DIY some tasks. I have no way of knowing if you have the skills needed to complete the tasks you are asking about, when in doubt seek professional assistance.

        My advice may be worth exactly what you pay me for it. :-) For the record I did not stay in a Holiday Inn Express last night.
         
        Posts: 900 | Location: Cary, NC | Registered: Aug 17, 2006Reply With QuoteReport This Post
        posted Hide Post
        Well. I talkd to my brother and he said replacing the fan/blowere-relay switch is not anymore complicated than changing the capacitor that I did on the condensing unit. He said it is just located in a more tighter place and you have to remove the panel door of the attic unit vs the panel on the C-Unit outside.

        Here is an exact picture of the one I have, and you simply mirror the wires as they currently are.

        http://www.hvacpartsoutlet.com...elay-R8222D1014.aspx

        The confidence level that it is the fan relay switch [which houses the contacts] is pretty high bc when I tapped on the panel housing [while the fan was blowing and the t-stat was in the off position] and the blower stopped, this meant the tapping disengaged the contacts and broke the circuit, thus stopping the fan. The other only explanation could be a wire was frayed and by tapping jarred or move the wire and the short was stopped. When I open the fan relay switch and see either heavy oxidation or a "welding-like appearance", then I know this was the culprit.

        I believe for $14.00, buying this part only to see if it fixes it, I am not out too much. I will take pictures of all the wiring and make sure it all goes back the same. I know incorrect re-wiring can burn-out a transformer or something else, and that is main risk.

        So, I am going to give it a shot and will let you know who it goes. My brother just installed an entire AC/Heating system in his weekend place and is very, very electrical savvy, so I have him to call if I need something.

        Thanks again and I surely appreciate all the advice on the boards...something about completing a task like this that really gives a nice chunk of personal satisfaction.

        Regards,
        tstex
         
        Posts: 378 | Registered: Jun 23, 2010Reply With QuoteReport This Post
        posted Hide Post
        quote:
        Originally posted by tstex:
        Well. I talkd to my brother and he said replacing the fan/blowere-relay switch is not anymore complicated than changing the capacitor that I did on the condensing unit. He said it is just located in a more tighter place and you have to remove the panel door of the attic unit vs the panel on the C-Unit outside.

        Here is an exact picture of the one I have, and you simply mirror the wires as they currently are.

        http://www.hvacpartsoutlet.com...elay-R8222D1014.aspx

        The confidence level that it is the fan relay switch [which houses the contacts] is pretty high bc when I tapped on the panel housing [while the fan was blowing and the t-stat was in the off position] and the blower stopped, this meant the tapping disengaged the contacts and broke the circuit, thus stopping the fan. The other only explanation could be a wire was frayed and by tapping jarred or moved the wire and the short was stopped. When I open the fan relay switch and see either heavy oxidation or a "welding-like appearance", then I know this was the culprit.

        I believe for $14.00, buying this part only to see if it fixes it, I am not out too much. I will take pictures of all the wiring and make sure it all goes back the same. I know incorrect re-wiring can burn-out a transformer or something else, and that is main risk.

        So, I am going to give it a shot and will let you know who it goes. My brother just installed an entire AC/Heating system in his weekend place and is very, very electrical savvy, so I have him to call if I need something.

        Thanks again and I surely appreciate all the advice on the boards...something about completing a task like this that really gives a nice chunk of personal satisfaction.

        Regards,
        tstex
         
        Posts: 378 | Registered: Jun 23, 2010Reply With QuoteReport This Post
        posted Hide Post
        relays are a common failure point. being a guy who has gone component-level on computers, ham radio equipment, did a little work on a mass spectrometer once at a private college, and so on, I would replace the relay. you diagnosed the issue correctly.

        it is ESSENTIAL as in life-critical to make sure the breaker has been thrown, locked out or labelled, and absence of voltage confirmed with a meter or non-contact tester before replacement. AC units are 240 volts. when I work on something carrying more than 12 volts, I set the unplugged line cord on the bench so I can frequently confirm it isn't powerable, and I use a "chicken stick" shorting prod and jumpers across any hign-voltage supplies profusely.

        This message has been edited. Last edited by: swschrad,


        sig: if this is a new economy, how come they still want my old-fashioned money?
         
        Posts: 5866 | Location: North Burbs, MN | Registered: Mar 14, 2007Reply With QuoteReport This Post
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