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  1. #1

    Blower hum at startup

    My blower has started making a huming noise at startup for a few seconds until it is up to speed. A technician looked/listened and thought that the motor was going bad. The furnace is from 1999, so he recommeded furnace replacement instead of replacing the blower motor. In everyones experience, how long might we expect the blower motor to last before total failure? Is it reasonable to replace the entire furnace if it is 11-12yrs old?

    He also recommended replacing the A-coil at the same time because of some previously repaired corrison on the A-coil housing/pan. Strictly speaking, there is no need to change the A-coil when replacing the furnace, right?

    Many thanks for the input. I look forward to hearing what you have to say.

  2. #2
    Join Date
    Jun 2008
    Location
    Cincinnati, Ohio
    Posts
    2,176
    At this stage of the game, you are probably better off replacing the blower motor and start capacitor. ASHRAE has determined the average useful life of a residential split-system as 15-17 years.

    If the A coil isn't leaking refrigerant at this point, it's best to leave it alone.

    Keep it in the back of your mind, however, that your system is getting older, and you will need to spend a little money on maintenance and repairs. Start putting money aside now for when you ultimately do need to replace the system. You will know that time when the repair quote makes no economic sense when compared to replacement cost.

  3. #3
    Join Date
    Dec 2002
    Location
    Houston,Tx.
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    16,121
    Is this hum in the heat mode or a/c mode or both?
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  4. #4
    Thanks for the input.

    The hum started while we have been in heat mode. It wasnt there the first time we turned on the furnace and I dont know if it is there with the ac.

  5. #5
    Join Date
    Jul 2009
    Location
    Ontario, Canada
    Posts
    913
    Without knowing the current state of the rest the furnace, I would just replace the blower motor and run capacitor. The hum you hear now is a definite sign that the motor will fail soon. It's too early to replace the furnace, unless ofcourse there are other issues with it or you may want to look at any available rebates/grants for replacing the furnace.

    If your replacing the furnace only, the A coil does not need to be replaced unless there is current damage to it(Ie cracked drain pan)

  6. #6
    He said that there was some corrision on the a-coil enclosure and a second pan had been added. We moved into the home recently. I checked this afternoon and confirmed the corrision or hole through the side corner (about 1" x 2"). I think his recommendation to replace the a coil is probably good.

  7. #7
    Join Date
    Sep 2006
    Location
    Montana
    Posts
    983
    Quote Originally Posted by Ensic View Post
    My blower has started making a huming noise at startup for a few seconds until it is up to speed. A technician looked/listened and thought that the motor was going bad. The furnace is from 1999, so he recommeded furnace replacement instead of replacing the blower motor. In everyones experience, how long might we expect the blower motor to last before total failure? Is it reasonable to replace the entire furnace if it is 11-12yrs old?

    He also recommended replacing the A-coil at the same time because of some previously repaired corrison on the A-coil housing/pan. Strictly speaking, there is no need to change the A-coil when replacing the furnace, right?

    Many thanks for the input. I look forward to hearing what you have to say.
    Did the tech do anything other than listen to it start? It's hard for us to know from here what it sounded like, but it could be a simple repair. Did he measure the capicitance of the run capacitor to verify it was still ok? Did he check the amp draw of the motor? Every once in a while I'll find a bad run cap that will cause a motor to not start or cause the motor to hum and take a while to come up to full speed. I would start there. If indeed the motor is going out, I would just replace the motor and run cap, unless you're wanting a higher efficient furnace or to take advantage of the tax credits and rebates available.

  8. #8
    Join Date
    Apr 2007
    Location
    Philadelphia
    Posts
    2,193
    It is hard to get a correct answer without anyone knowing what condition or efficiency your current system is running at. However in my experience it is better to replace the A-coil with the furnace, And it is better to do it all at once. if you put a new furnace in now, And you already had a leak in the A-coil, Do you really want to rip it all apart again in 2 years when the next leak is not repairable? The problem would be finding a coil to match your condenser as i am only assuming it is R-22 10 seer or lower.

  9. #9
    Join Date
    Sep 2006
    Location
    Montana
    Posts
    983
    Quote Originally Posted by d_griff View Post
    It is hard to get a correct answer without anyone knowing what condition or efficiency your current system is running at. However in my experience it is better to replace the A-coil with the furnace, And it is better to do it all at once. if you put a new furnace in now, And you already had a leak in the A-coil, Do you really want to rip it all apart again in 2 years when the next leak is not repairable? The problem would be finding a coil to match your condenser as i am only assuming it is R-22 10 seer or lower.
    You can still use a 410-A coil with an R-22 system, just need to replace the metering device.

  10. #10
    Join Date
    Jan 2010
    Location
    over here
    Posts
    463
    Have em install a rescue ecotech.

  11. #11
    Join Date
    Dec 2010
    Location
    Saskatoon, Saskatchewan
    Posts
    7
    I thought that the oils were different for 22 and 410? I know the coils are the same just different tx, but don't you have to flush oil out of the coil if you were installing a 410 unit?

  12. #12
    Join Date
    Apr 2007
    Location
    Philadelphia
    Posts
    2,193
    Quote Originally Posted by Razor Jeff View Post
    I thought that the oils were different for 22 and 410? I know the coils are the same just different tx, but don't you have to flush oil out of the coil if you were installing a 410 unit?
    Not if you are keeping the same condenser. The Evap dont come with oil in them.
    And i know that they call some of the coils "Dual refrigerant". But it will change the way your system works when you put a new 13 seer coil on an old 8 seer condenser. I didnt say it wouldnt work, I just think it would be better replaced IMHO

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