Carrier model 38ycb030300 a/c unit top fan doesn't spin

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  #41  
Old 02-12-12, 03:37 PM
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OK, your system uses a low pressure sensor, high pressure sensor, and discharge temp switch in series with the contactor coil. You are going to need a Pro to check the refrigerant charge is correct.
 
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  #42  
Old 02-12-12, 03:38 PM
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Thanks so much for all your help, I appreciate the time you have taken!!
 
  #43  
Old 02-12-12, 03:40 PM
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no problem....I'm happy to help.
 
  #44  
Old 02-12-12, 08:18 PM
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Just curious, did the unit as a whole run properly up until you had the fan motor issue. Was there ever a complaint about it heating or cooling in the last 3 months?

Also when the new fan motor engages (even intermittenly) does the compressor come on and stay on? even after the fan motor has cut out?

Reason I ask is I had a problem child last summer that sounds kind of like this.
 
  #45  
Old 02-13-12, 04:57 AM
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I believe it was working ok up until now, the compressor stays on I think, the unit still blows good heat into the house. My roommate did say something about hearing some pretty nasty noises coming from outside where the machine was a few weeks before I noticed the problem here...was probably the fan motor dying.
 
  #46  
Old 02-13-12, 06:52 AM
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Ok, sooooo if the unit worked fine up until now. The fan motor was changed with the exact one and matched with a new run capacitor and the wiring is double/triple checked with all of the leads secure where they need to be, then I would back up a second if you want to troubleshoot some more.

the refridgerant charge is probably fine unless something dramatic happened in the not so distant past and since you said there has been no complaint on performance then you can probably rule that out for now. You can put down the volt meter and try this.

1. let the unit stabilze off for an hour or so. Dont turn it on or anything.
2. after that time has elapsed, with an insulated screwdriver, and holding said screwdriver by the insulated handle push down the black button on the left side of the contactor. Hold it down for 5 seconds then release it. There are two sides of the contactor the right is a bar and the left has a little button in the front of it.

Does the compressor come on and stay on?
Does the fan motor come on?
What exactly is the fan motor doing at this time?
 
  #47  
Old 02-13-12, 09:36 AM
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i'm having a hard time finding the button you're describing
 
  #48  
Old 02-13-12, 10:05 AM
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plunger/ button it closes with an audible click to allow the current to pass through. It is on the front of the contactor and the left side.

https://picasaweb.google.com/lh/phot...eat=directlink

between those green circles on that picture you have uploaded is the contactor plunger/button.
 
  #49  
Old 02-13-12, 10:08 AM
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ok gotcha. with all power off i held that in for 5-7 seconds, released it, then went back inside and turned it back on at the thermostat. i came back out and then flipped the outside switch. the fan came on and then did the same thing it's been doing.
 
  #50  
Old 02-13-12, 12:46 PM
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was the power on to the unit when you checked it at the contactor, i dont mean the thermostat but the outside switch. if power was not on then it must be on to check it.

redo the test if the power was not on

If the power was on at the unit when you pressed in the contactor for 5-7 seconds what happened? Did the compressor come on and stay on and did the fan motor operate normally?
 
  #51  
Old 02-13-12, 12:48 PM
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i'll do it that way when i get home from work and let you know. by the way what are my odds of electrocution? hopefully this little rubber handled pliers will hold up
 
  #52  
Old 02-13-12, 02:23 PM
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I dont think this thread needs to continue further. You already checked this by verifying voltages that I had you check. The compressor can not be staying on if your contactor coil is losing voltage when the fan drops out. CALL A PRO to have the refrigerant charge checked!

@phxheatpump - please read the whole thread from start to finish. Why are you making the OP recheck what has already been checked. Read the schematic that was posted by Houston204. The contactor coil voltage is dropping out due to one of the safety switches in series with the contactor coil circuit. Most likely it is the low pressure switch. This needs to be checked by an EPA certified technician.
 
  #53  
Old 02-13-12, 02:36 PM
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as a final note i did the last test requested. when i pushed in the black button the fan came right on and stayed on as long as i would hold the button in
 
  #54  
Old 02-13-12, 02:41 PM
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We already knew that would happen by the tests you had previously performed. The test he had you perform was useless. Please call a PRO.
 
  #55  
Old 02-13-12, 03:02 PM
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Ok great mrcastleberg, unfortunately you now probably have two good motors and run caps so keep them in the future in case they actually do fail.

When you do call a Tech out be sure to give him the lowdown from start to finish. Sadly, pressure switches will only come into play after the unit has run for a while, sometimes a short while, but a while. When your unit has stabilized (after an hour of sit time, say) and upon start up still have the fan motor intermittenly operating then you are clearly dealing with something else. The chances of a freon loss now with no complaint lately of performance issues is unlikely but still possible. I had a strange one that sounded a bit like this and after checking the defrost board and everything else, upped the hp of the motor from a 1/4 to 1/2 same rpm and ran like a champ. Was very weird....
Please post up a reply when you do have it looked at and give an update on the issue.
good luck to you.
 

Last edited by PHXHEATPUMP; 02-13-12 at 03:17 PM. Reason: add
  #56  
Old 02-13-12, 03:36 PM
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The 'useless test' I asked mrcastleberg to do, if done first, would confirm the original fan motor was operative and running fine. Checking at the contactor is one of the first things to do and it tells you alot right off the bat. Plus for DIY it is alot easier than trying to teach someone to use a voltmeter for the first time.
 
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