Original message
| sawdust
 |  "Trane XE1000 Condenser unit fan inop-hums"
, posted Thu 8 May 18:20  
I have the same problem I've seen on several forums with the Trane XE1000 fan on the condenser unit not working. Mine makes a loud hum when power is applied and the inside fan is running. When testing with a multimeter, I have 120 VAC on all contacts of the contactor and the capacitor. The contactor is functioning as it should, I can see the contacts pulling down when energized, and there is 24 VDC on the coil contact also. I tested the power going to the fan by inserting the meter leads into a quick disconnect blade type plug between the contactor and fan, the capacitor and fan, and a power relay and the fan. All had 120 VAC on them when the fan was humming. The blades spin freely when spun with a pencil, but it won't run. I also isolated and tested resistance between the three wires leading to the fan. From black to brown, (power relay to capacitor) I read 78 Ohms, from black to purple, (power relay to contactor) I read 31 Ohms, and from brown to purple, capacitor to contactor) I read 78 Ohms. I'm familiar with electronics but I'm no engineer. Is the fan motor bad?
Aviation Electrical Systems Tech.
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Replies:
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| sawdust
| "Re(1):Trane XE1000 Condenser unit fan inop-hu" , posted Sat 10 May 21:22
Guess what? The Capacitor is not supposed to be convex at the top. Looking at it when installed, it looks uniform and straight, so I thought it was supposed to be that way. When I removed it to get the MFD and voltage required for a new one, I noticed that the top is bulging out like a soda can in the freezer. When I googled a replacement, the photos show flat on top, in fact it's supposed to be recessed a little. All the other posts that say look for bulging or leaking, but I expected the sides or bottom to be bulging or the bulge to be uneven. I think I found the problem. I'm going to replace the contactor at the same time, it looks pretty humble.
Aviation Electrical Systems Tech.
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| sawdust
| "Re(1):Trane XE1000 Condenser unit fan inop-hu" , posted Thu 8 May 21:33
OK, I played with it some more after posting the first bit of info. I hooked up all the wires that I had disconnected and removed all the screws from the top of the unit. With the T-stat switch in cool and the motor humming, I lifted the lid and gave the fan a fast spin with a stick. It began to run under its own power, although it spun very slowly, maybe 300-400 rpm. I also killed power and spun it the other direction, and it did the same thing, so I think the capacitor, which is supposed to provide a second phase of ac power 120 degees from the primary phase, is missing. I disconnected the blade type connectors one at a time from the power relay, the capacitor lead, and the contactor. Don't worry, the quick disconnects are many inches from any live circuits and they are well insulated themselves. The motor died when the each of the leads from the contactor and power relay were disconnected, but disconnecting the capacitor lead had no effect, and did not spark when the two ends were tapped together.
Aviation Electrical Systems Tech.
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| | theduke03
| "Re(2):Trane XE1000 Condenser unit fan inop-hu" , posted Thu 8 May 21:59:
Check for 230v between Fan L1 and L2. If 230 then this eliminates the contactor and relay.
You can test a capacitor with ohmmeter on highest range (with power off, and capacitor discharged to ground first for safety).
Simply un-wire it and put leads across the 2 terminals. Ohms should drop towards 0 and then rise back up towards infinate. then switch leads and repeat, you should get same result. If this is so then capacitor is OK.
All that's left is the motor. Did you check amps and compare to nameplate FLA rating?
I don't recommend playing with those connections with power on. Being an electrical guy, I should'nt have to tell you that. just throw the disconnect first and live to get whacked another day!
"My dad was the most feared furnace fighter in Northern Indiana."
[this message was edited by theduke03 on Thu 8 May 22:01] |
| learner
| "Re(1):Trane XE1000 Condenser unit fan inop-hu" , posted Thu 8 May 19:39
Hi,
When it was humming, did you give it a little spin with a stick?
Probably capacitor problem.
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