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    Pdan05's Avatar
    Pdan05 Posts: 1, Reputation: 1
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    #1

    Oct 10, 2009, 07:34 AM
    Why A/C Blower will not turn on?
    I have a Carrier 8000 WeatherMaker in the crawl space of my home. The BLOWER MOTOR will not turn on when the unit is turned on at the thermostat. The a/c condenser fan motor will come on as well will the heater(pilot & burners). They turn off after a few seconds, however the blower motor never comes on. There is a constance low volume winding noise that's on all the time, it shuts off when I remove the access panel to the blower section.( safety shut-off switch I assume). Best answer please... What do you think the problem is?
    hvac1000's Avatar
    hvac1000 Posts: 14,540, Reputation: 435
    Heating & Air Conditioning Expert
     
    #2

    Oct 10, 2009, 10:08 AM
    If the blower motor never comes on then the problem would be isloated to the blower motor/blower motor capacitor/or the wiring from the unit to the motor itself. On newer units there are control relays for the blower motor but they are usually mounted on the circuit board so that could also be a problem. Guess work is not a good thing so I recommend you or a professioanl HVAC person check the unit on site with a electric meter to determine exactly what part is defective and replace that part only to keep the expense down.

    BTW the noise you are talking about could be the motor trying to start.
    EconomyAC's Avatar
    EconomyAC Posts: 11, Reputation: 1
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    #3

    Oct 10, 2009, 02:11 PM

    Sounds like you may have a bad fan motor, but a quick check is to simply put your thermostat switch from auto to on, and see if the blower motor runs.

    Thermostats allow the heating device to turn the fan on by it's own controls, and is usually in the low speed for the heating half of your furnace/AC system. When you put the thermostat in the "on" position, it will almost always go to the AC position or high speed on your blower motor.

    You can all check this the next time your furnace is running and you remember this, by simply turning the fan switch on your thermostat to the "on" position, and the blower motor should increase in speed, which might not be as noticeable if the blower motor speed for the heat cycle is wired to the medium or medium-high. Most of the common installations will have the furnace wired to the low speed and you should easily notice the pick up in speed when you turn your stat fan switch to the "on" position.

    This will also check and see if the low speed windings are shot, but most of the time if one set of windings are shot, then it is time to replace the motor, as the rest of the windings are probably not far behind in going kaputt.

    In this case, where you have ignition, and flame, then the unit goes out on high limit or no proof of fan, you are probably in need of a new blower motor, as we know that you have line voltage to run the transformer, which is what is needed to run the low voltage components. There is just a few things left that could be keeping the blower motor from coming on besides a bad motor and none of them are good.

    One quick check you can do, with the door off to kill the power, and that is to grab the squirrel cage if you can and move it back and forth. If it clunks back and forth, your bushings are shot, and so is your blower motor, and you know what you have to do next. The good news, is this is one of the cheapest components to replace in a furnace, with blower motors selling for under 50.00 if you shop around.

    This is where the universal motor is a good item to have, and while it may be tempting to super-size it, don't do it. Just because it costs the same for 1/2 hp motor as it does for your 1/4hp, replace it with the right size to get the best efficiency.

    Yes, there are times when it is better to go to a bigger motor, but not very often. The speeds will be the same, so you won't get more air over the coil, unless the motor was way undersized in the first place, so you want to use the motor that was sized for the unit and save on your power bill.

    This might be a time to talk about the SF or S. F. rating on your motor. This stands for Service Factor, and most blower motors should be rated at 1.35, which means that it is overbuilt by .35 and will last a long time. If you want a better explanation of service factor, just ask and we will start a new thread.

    Dan

    Dan
    mygirlsdad77's Avatar
    mygirlsdad77 Posts: 5,713, Reputation: 339
    Plumbing Expert
     
    #4

    Oct 10, 2009, 02:29 PM
    [QUOTE= The good news, is this is one of the cheapest components to replace in a furnace, with blower motors selling for under 50.00 if you shop around.

    Dan[/QUOTE]

    Can you tell me where you find blower motors for under 50 bucks? And are they new, rebuilt, used, and do they come with factory warranty? I can think of a quite a few items on a modern furnace that are cheaper than a blower motor(unless of course I could get the motors for less than $50. Overall, if you buy factory replacement motor, its going to cost a lot more than $50, and I suggest getting a factory replacement, or take your chances, either way, I think its going to be more than 50.
    mygirlsdad77's Avatar
    mygirlsdad77 Posts: 5,713, Reputation: 339
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    #5

    Oct 10, 2009, 02:31 PM
    [QUOTE=hvac1000

    BTW the noise you are talking about could be the motor trying to start.[/QUOTE]

    Or just the humming of the transformer.
    hvac1000's Avatar
    hvac1000 Posts: 14,540, Reputation: 435
    Heating & Air Conditioning Expert
     
    #6

    Oct 10, 2009, 05:20 PM
    Can you tell me where you find blower motors for under 50 bucks?

    Sure I can. Ebay and the 50.00 price includes shipping to your door. Use a sniper tool for bidding since it works almost every time. LOL
    EconomyAC's Avatar
    EconomyAC Posts: 11, Reputation: 1
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    #7

    Oct 11, 2009, 11:38 AM
    Quote Originally Posted by mygirlsdad77 View Post
    Can you tell me where you find blower motors for under 50 bucks? And are they new, rebuilt, used, and do they come with factory warranty? I can think of a quite a few items on a modern furnace that are cheaper than a blower motor(unless of course i could get the motors for less than $50. Overall, if you buy factory replacement motor, its gonna cost a lot more than $50, and i suggest getting a factory replacement, or take your chances, either way, i think its gonna be more than 50.
    While I usually don't suffer fools, this answer is to satisfy more than your scathing retort. Within a minute, I found several places on the web that will sell a blower motor for 70.00 just using Google and this is not even a bargain, and is retail pricing. If you were to contact your local HVAC wholesaler, and get a price quote, you will find that many of these motors can be had for under 50.00.

    Regarding the condition of the motor... Most of the replacement motors are just as good as the motor they are to replace, and in fact, often times they are exactly the same brand and configuration. The blower motor on most furnaces and air handlers are almost all direct drive and only a few are belt driven, which surprisingly, those motors are even cheaper at less then 40.00. Just make sure the SF is 1.35 and that will assure you that the motor will last a good long time in normal duty.

    You really should do your research before you jump on someone's post when it is apparent that you are not a very good service tech to be making such remarks as inquiring if it is a direct factory replacement motor, when you should be more concerned if the motor is the same configuration and therefore will meet the needs of the unit, for 30% of the cost of buying from the factory that made the unit and is simply over-charging you for the very same item. It takes a good tech to know the value of replacement parts and which ones can be replaced with off the shelf parts found at the local HVAC counter, and which ones need to be replaced with factory direct parts. A good tech will be able to do the job and save his customers money, while still doing the job correctly, and thus keeping that customer and probably getting a few referrals, where you would just replace the part with an over priced one and in your ignorance, make the customer upset over the high cost of the ticket and never hear from them again, nor anyone that they will talk to and tell of the high prices you charged. I guess this is where experience is a great asset, and arrogance just loses out. Thanks for showing it.

    Dan
    mygirlsdad77's Avatar
    mygirlsdad77 Posts: 5,713, Reputation: 339
    Plumbing Expert
     
    #8

    Oct 11, 2009, 12:35 PM

    Hi EconomyAC, welcome to askmehelpdesk, see you around, and looking forward to your helpful advice.
    hvacservicetech_07's Avatar
    hvacservicetech_07 Posts: 1,083, Reputation: 75
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    #9

    Oct 11, 2009, 01:49 PM

    EconomyAc, must all of your posts look like novels? It is very possible to find a 50 dollar blower motor on the net,will the buyer have the know-how to install it? Maybe. However,I promise you there are not many service companys that will sell or install a blower motor 50 bucks! Does that make them all crappy service guys? Hell no,it's the name of the game, we are here to make money like any other trade. So for you to suggest that selling a customer a blower motor for over our cost, that we are ripping them off,you sir are a true nut job! FYI: If you keep your post under 10,000 words next time, more people may read it...
    EconomyAC's Avatar
    EconomyAC Posts: 11, Reputation: 1
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    #10

    Oct 13, 2009, 05:04 AM
    Quote Originally Posted by hvacservicetech_07 View Post
    EconomyAc, must all of your posts look like novels? It is very possible to find a 50 dollar blower motor on the net,will the buyer have the know-how to install it? maybe. However,I promise you there are not many service companys that will sell or install a blower motor 50 bucks! Does that make them all crappy service guys? Hell no,it's the name of the game, we are here to make money like any other trade. So for you to suggest that selling a customer a blower motor for over our cost, that we are ripping them off,you sir are a true nut job! FYI: If you keep your post under 10,000 words next time, more people may read it.....
    We weren't discussing how much to charge, just what the motors could be purchased for, although it was mentioned that purchasing a motor from one of the dealers to get the direct replacement would be very expensive. That was my main point, besides the motors sold are often the same brand as the ones sold by the dealers.

    We also did not discuss who would be installing the motor, but since you have stuck your nose in here, I would like to know what it is that bothers you about long posts? Your inability to read? If people get tiresome of my long posts, they know ro just move on, and maybe that is what you should do.

    They don't call me motormouth for nothing, is something I often say, as it is true. I do write long posts and often treat a topic as if someone new to the trade or is a DIY'r and is reading it, which is most often the case, or they would have simply called a reputable service contractor and wouldn't be here looking for information or a solution.

    I am not always correct and I learn on here as well, but I am not so insecure that I would berate someone on their length of post and just be posting to insult. I also have a tendency to use big words... Is this a problem for you? I just wanted to check as you seem to have designated yourself as the message nazi.

    In all of the forums I get involved with, I have always made lengthy posts and try to include as much information as possible. Some don't care for it and simply move on to the next message, but a lot of them read everyword and I have been thanked many times for my long explanations as a lot of the people that come to help forums are searching for information.

    While I never mind being corrected where my information is wrong or outdated, I do have a problem with someone such as yourself that feels he needs to point out what they don't like and not address what is important.

    In another thread I had posted about the control transformers not having a polarity on the low voltage side, since it is a simple induction transformer. I also brought up why I usually ran a 5th wire to be able to include an isolation relay in the control circuit in the early circuit boards, and another tech responded with a better answer, updating mine, and I was thankful for the update. I now know why we had all those problems with the early circuit boards that had so many intermittant problems. If I had not made that post on transformers and my comment on polarity, it would neve have been addressed, and a lot of people would have remained ignorant of what is current in that area, including me.

    So if you don't like my novel approach (pun intended), please feel comfortable to just add me to your ignore list and it will eliminate any problems you may have with my long posts. I came here by hitting a link while googling for a replacement fan motor for a friend of mine. I got to reading some of the posts and thought I could add to the topics. I also found that since I have retired, there is some stuff that is new to be learned and even some stuff that is old to be re-learned, and found myself enjoying the forum, until now.

    Is this post long enough yet? While I am not as bad as my wife, who has been accused of never leaving a thought unexpressed, I too have that tendency, so either suck it up or just quit reading my posts... It really is quite simple, such as yourself...

    Dan
    EconomyAC's Avatar
    EconomyAC Posts: 11, Reputation: 1
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    #11

    Oct 13, 2009, 05:14 AM
    Quote Originally Posted by mygirlsdad77 View Post
    Hi EconomyAC,, welcome to askmehelpdesk, see you around, and looking forward to your helpful advice.
    Thank you and I must apologize for my last post. I was rude and defensive. I thought you had taken a cheap shot at me, and responded hatefully and should not have.

    Sometimes it is hard to convey emotions on a chat forum, and things can get out of hand very quickly if not nipped as Barney Fife would say.

    I just want to say I'm sorry for what I said and getting off on the wrong foot. You have shown me that you are a better man than I when it comes to forum etiquette, and I am grateful.

    Dan
    mygirlsdad77's Avatar
    mygirlsdad77 Posts: 5,713, Reputation: 339
    Plumbing Expert
     
    #12

    Oct 13, 2009, 03:48 PM

    No problem, I only lost a night or two of sleep over it, lol, but true. I was incorrect in my way of posting on this subject. I think we should all just forget all that has been said on this one forrum, and move on to the next, no hard feelings. Take care. Lee.
    reddog9608's Avatar
    reddog9608 Posts: 3, Reputation: 1
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    #13

    Oct 13, 2009, 04:13 PM
    Quote Originally Posted by hvac1000 View Post
    if the blower motor never comes on then the problem would be isloated to the blower motor/blower motor capacitor/or the wiring from the unit to the motor itself. On newer units there are control relays for the blower motor but they are usually mounted on the circuit board so that could also be a problem. Guess work is not a good thing so i recommend you or a professioanl hvac person check the unit on site with a electric meter to determine exactly what part is defective and replace that part only to keep the expense down.

    Btw the noise you are talking about could be the motor trying to start.
    Sopunds like you have a gas furance the problem maybe in the fan cycle switch not heating up to bring on the fan. The noise could be coming from the transformer. Wich is normal
    hvacservicetech_07's Avatar
    hvacservicetech_07 Posts: 1,083, Reputation: 75
    Ultra Member
     
    #14

    Oct 13, 2009, 08:54 PM

    EconomyAC, While I usually don't suffer fools?? You sir are an arrogant know it all pile of sh1t in my book. You can keep your future comments towards me to yourself and I'll do the same. I don't like how you addressed another person who had a valid question. Enjoy your retirement!
    jjpetruska's Avatar
    jjpetruska Posts: 1, Reputation: 1
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    #15

    Apr 9, 2013, 01:24 PM
    My blower will not turn on in ac mode. Turns on fine for heat. Turns on if you jump G and R. compressor for ac turns on fine. If I jump G and R and turn on ac via thermostat blower will turn off in a few seconds. I can hear a double click of the relays when I turn on the ac. I replaced the run capacitor for the blower last year. I did change the thermostat a few months ago and haven't run the ac since. I am almost dertain that the wiring is correct. d


    Joe

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