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  1. #1
    Join Date
    Jul 2005
    Posts
    7
    Hello,

    I have a problem I'm hoping someone can help me with. We have a Bryant Plus
    80 with an Air Conditioner unit. I haven't used the Air Con for a few days
    and today I turned it on and there was no fan. I checked and found the CPU
    board just making a buzzing sound. I checked to make sure the fan spinned
    freely, which it does. I checked to see if there was 24VAC from the
    transformer and there is. I reseated all the connectors on the board, but
    there was no change. I did not remove the board though, so the top
    connections were not reseated, but they seem to be for the heating area.
    One note I should mention is when the Electronic air cleaner filter was
    connected to the 24VAC output of the transformer the motor was going on and
    off, so I put a regular air filter in and that solved that problem for the
    moment. Now I'm wondering if the transformer is not putting out enough
    power for the blower relay to kick on all the way, or if the relay is bad
    and needs more power than it has been getting. I don't want to replace the
    board if I can repair it. I'd appreciate any help you can offer, so I can
    test further.

    Thank You,

    Bob


  2. #2
    Join Date
    May 2001
    Location
    Bennington, Vermont U.S.A.
    Posts
    13,864
    You may have 24V at the transformer but what voltage do you have at the relay coil? That is what I would check first.

    Second thing I would check is to see if there is any pitting or corrosion on the line voltage contacts. Then check the line voltage. One of these 3 things are usually the cause of a buzzing relay.

  3. #3
    Join Date
    Jul 2005
    Posts
    7
    Thanks for your response. How would I check the voltage at the coil? Wouldn't I have to remove the board? There was (2) contacts protruding from the relay that had voltage around 24VAC. I don't think the cover comes off, though I didn't try too hard for fear of breaking it.

  4. #4
    Join Date
    Jul 2005
    Posts
    7
    The Model is 395CAV036090, Series C.

  5. #5
    Join Date
    Nov 2004
    Posts
    2,927
    Is it variable speed blower?
    Sometimes there are compounding complexities of multiple variables that are not intuitively obvious

  6. #6
    Join Date
    Jul 2005
    Posts
    7
    I think it is, but I'm not 100% sure. Why do you ask, would this make a difference? Thanks, Bob

  7. #7
    Join Date
    Nov 2004
    Posts
    2,927
    yes it makes a difference,also which type of set up it is

    If this is your only resource for troubleshooting this thing ,then you need to find a qualified technician to help.

    I am not sure I understand if the blower will come on in fan mode or if all modes are not working,ect...
    (the relay has 24 volts,thats good)

    I dont have a anything but wild guesses,based on the fact that bryant should be similar to carrier.

    Is this on a gas furace?I dont recognise model numbers very well,they all look alike.How old is it?
    Sometimes there are compounding complexities of multiple variables that are not intuitively obvious

  8. #8
    Join Date
    Aug 2001
    Posts
    1,936
    does the condensing unit come when you turn thermostat down, does fan come on when you turn fan switch to on

  9. #9
    Join Date
    Jul 2005
    Posts
    7
    Thanks for your resonses, it is a gas furnace. I think is from 1993. The blower does not come on at all. I was thinking about disconnecting the wires to the blower and see if all I get still is the buzzing. It seems like either I'm not getting enough power to trip the relay or the contact points are bad. This board was replaced about 3 or 4 years ago.

    I just tried it with the fan on switch and it sizzed and smoked, so now I don't know if it's fried or not. The relays above the blower relay is the ones that smoked. There also seems to be a little dripping, perhaps from condensation in ther and could have dripped down to the board.

  10. #10
    Join Date
    Aug 2001
    Posts
    1,936
    there you troubleshot your problem its a bad board

  11. #11
    Join Date
    Jul 2005
    Posts
    7
    The board would be very easy to replace, do you know where I may be able to buy one without the mark up? I repair computers and would not have any problem replacing it. I also found out the shower above the furnace had a plastic pipe for the shower head that was broken and that's where the water came from.

  12. #12
    Join Date
    Jul 2002
    Location
    Slacking off right now
    Posts
    7,546
    EBAY
    www.vetopropac.com - The best tool bags on the market - The offical tool bag of choice by techs everywhere

    Arguing with some people is like wrestling a pig - eventually you realise the pig actually enjoys it

    Gonads serve a useful purpose but are no substitute for brains

  13. #13
    Why are we troubleshooting DIY problems? Isn't there a rule specifically prohibiting this?

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