new contactor?
#1
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new contactor?
ok, so my AC "died" last night. I couldn't even turn on the fan or heat, nevermind the AC.
Today when i got home i dismantled the inside furnace and pulled a burnt 3amp fuse out and replaced it. I also found my filter to be super-dirty, which got replaced as well. Heat and fan work now, but no AC.
I unbuttoned the unit outside and checked to see if the fan would move freely, which it did. Also the capacitor isn't swollen at all. The contactor looks fine at first glance... although i'm not really sure whats going on there.
With power hooked up, i can press the spring on the contactor (see picture) and the AC will kick on. So.. does this mean faulty contactor?
I also tried shorting the "Y" wire to the "RC" wire behind the thermostat to make sure it wasn't that. The unit outside did nothing when i shorted it.
I think what happened is... the inside return fan had to work extra hard because the filter was dirty.. which burnt the fuse and locked the contactor?
Today when i got home i dismantled the inside furnace and pulled a burnt 3amp fuse out and replaced it. I also found my filter to be super-dirty, which got replaced as well. Heat and fan work now, but no AC.
I unbuttoned the unit outside and checked to see if the fan would move freely, which it did. Also the capacitor isn't swollen at all. The contactor looks fine at first glance... although i'm not really sure whats going on there.
With power hooked up, i can press the spring on the contactor (see picture) and the AC will kick on. So.. does this mean faulty contactor?
I also tried shorting the "Y" wire to the "RC" wire behind the thermostat to make sure it wasn't that. The unit outside did nothing when i shorted it.
I think what happened is... the inside return fan had to work extra hard because the filter was dirty.. which burnt the fuse and locked the contactor?
#2
To the sides of the tip of the screwdriver (on the picture you have posted) notice a thin yellow and black wires which (with space donnectors) connect to the contactor coil terminals.
24V should be available across these two terminals any time the t-stat inside the house calls for cooling. So go ahead, have the thermostat call for cooling and armed with a voltmenter check to see if you read 24V there. IF SO, the contactor is bad. But if you do not have 24V there, then trace the yellow and black wires inside the furnace and see where do they connect. The yellow should connect to a "Y" terminal on some sort of a terminal strip; the black to a "C" labeled terminal. Check for 24V there too...if you do have 24V here, the cable going outdoors is bad.
The furnace may have a built-in board with a delay function...your thermostat (if digital) may have that as well. So do not panic if you do not get 24V right away. Give up to 10 minutes for it to happen.
Give feedback and we'll take it from here.
24V should be available across these two terminals any time the t-stat inside the house calls for cooling. So go ahead, have the thermostat call for cooling and armed with a voltmenter check to see if you read 24V there. IF SO, the contactor is bad. But if you do not have 24V there, then trace the yellow and black wires inside the furnace and see where do they connect. The yellow should connect to a "Y" terminal on some sort of a terminal strip; the black to a "C" labeled terminal. Check for 24V there too...if you do have 24V here, the cable going outdoors is bad.
The furnace may have a built-in board with a delay function...your thermostat (if digital) may have that as well. So do not panic if you do not get 24V right away. Give up to 10 minutes for it to happen.
Give feedback and we'll take it from here.
Last edited by pflor; 06-03-08 at 06:08 AM.
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How'd you do that
donbondave...
The photo is a great idea. How you do dat? {:-)
I have a dig camera, SD chip reader, computer and scanner (if I need to post schematics for pflor). Just point me in the right direction. {:-)
Jake
The photo is a great idea. How you do dat? {:-)
I have a dig camera, SD chip reader, computer and scanner (if I need to post schematics for pflor). Just point me in the right direction. {:-)
Jake
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i ended up replacing the contactor, another 3 amp fuse, and the transformer inside which wasn't working right. All is well now. total cost was $56, and took me about 4 hours to figure out.
if you want to post a pic... just click the "image" button on the toolbar on top. The toolbar is only available when you go to reply to a message here, or create a new post. You'll have to find an image host to provide the picture for you... i use "flickr". Post the picture to flickr, then copy the hyperlink.. then click the image button, then paste the link.
if you want to post a pic... just click the "image" button on the toolbar on top. The toolbar is only available when you go to reply to a message here, or create a new post. You'll have to find an image host to provide the picture for you... i use "flickr". Post the picture to flickr, then copy the hyperlink.. then click the image button, then paste the link.