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Sorry for the delay on part number. Trane board 6400-0882-01 rev e. Assy 6400-0883-03 rev n.

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Originally Posted by jdblack

you need to upgrade the main control board. the problem gets solved by shutting down the first stage for ten seconds then bring both stages on together. this fires all three fans at the same time. its the only repair because once you get a fan pinwheeling it cant overcome when it starts.

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As I posted earlier, the first stage does shut down for about five to ten seconds then brings on both stages. Condenser fan three would run backwards. After replacing the motor and letting the unit run on its own, the fan was running the correct direction.

I have another unit doing the same thing at times. I hate to replace the motor since it's still running. It seems that I have read about a device that installs on motors to prevent the blades from spinning backwards. I need to look into more.

Originally Posted by jdblack

you need to upgrade the main control board. the problem gets solved by shutting down the first stage for ten seconds then bring both stages on together. this fires all three fans at the same time. its the only repair because once you get a fan pinwheeling it cant overcome when it starts.

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That is a two fold repair in that in a two stage circuit with a tandem compressor as the second stage, it is very common in a high ambient condition that the short cycling can not over come the head pressure on such a short delay. This will create a high LRA and trip the circuit breaker depending on which circuit short cycled.

It sounds like Trane has changed the starting strategy with this new board.

_______________
Understand the symptoms and you will find the solution.

Originally Posted by jdblack

you need to upgrade the main control board. the problem gets solved by shutting down the first stage for ten seconds then bring both stages on together. this fires all three fans at the same time. its the only repair because once you get a fan pinwheeling it cant overcome when it starts.

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Is there a new bulletin on this? And is this for the Microtel UCM or Reliatel.
I wonder if you know what the new revision number is for the updated UCM board.

Thats definitely a solution.

you need to upgrade the main control board. the problem gets solved by shutting down the first stage for ten seconds then bring both stages on together. this fires all three fans at the same time. its the only repair because once you get a fan pinwheeling it cant overcome when it starts.

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That run cap is usually rated at 25 MFD and any thing less would cause the symptoms which you are having. Recheck actual microfarad reading and verify that this is a quality run cap, GE or OEM.

Just some info on low ambient control and condenser fan motor operation which is controlled by the outside air sensor.

Outdoor Motor (ODM2) will be turned “OFF” since the UCP is sensing a low ambient
condition.

I have had Voyagers with the same symptoms and going off on high head pressure. Found that the OSA sensor had a degraded performance and was out of calibration by 10 degrees. It ohm'd out just fine but had a voltage drop which was inconsistent with actual temperature. Changed out the sensor ($9.00) and haven't been back since.

Per Trane: During low ambient operation compressor run time is counted and
accumulated by the UCP. Low ambient operation is defined as 55° F for single condenser fan units, and 40° F for dual condenser fan units.

Hope this helps

_______________________
Understand the symptoms and you will find a solution.

Originally Posted by hands

I replaced the capacitor for fan three first, but it didn't make a difference. I then tested the other two capacitors and they were good. The thing that got me was I could switch the plug connectors and the motor would run fine. I switched around fan one and fan three so three was the first fan and it ran good, but then the other fan one would run backwards and so on. I was thinking the motors were getting weak. But the new motor did the same thing when I ran them in test mode.

Looks like a wiring issue at the capacitor since a new motor did the same, check the diagram and wire #'s that land on the cap for the motor that is going backwards and verify that the common and capacitor lead are reversed at the capacitor. Then reverse the two leads at the capacitor (leaving the common feed to the caps in place) and it should now spin correct. They are all the same color so it's easy to get them mixed up.

Good Luck...

Did you check voltage to motors when they run backwards and amp draw ?

Originally Posted by Workin4TheMan

The only problem I have had with fans spinning backwards on this unit (and it was twice in one summer) was a 2 yr old unit that the caps failed on at different times. First was fan 3, then one of the 2 for the first stage. Replaced both caps only, motors were fine. Haven't had that problem since. Are you sure you changed the right cap? And did you check the other 2?

Had a ton of cap failures in the last 2 yrs...........

I replaced the capacitor for fan three first, but it didn't make a difference. I then tested the other two capacitors and they were good. The thing that got me was I could switch the plug connectors and the motor would run fine. I switched around fan one and fan three so three was the first fan and it ran good, but then the other fan one would run backwards and so on. I was thinking the motors were getting weak. But the new motor did the same thing when I ran them in test mode.

The only problem I have had with fans spinning backwards on this unit (and it was twice in one summer) was a 2 yr old unit that the caps failed on at different times. First was fan 3, then one of the 2 for the first stage. Replaced both caps only, motors were fine. Haven't had that problem since. Are you sure you changed the right cap? And did you check the other 2?

Had a ton of cap failures in the last 2 yrs...........

Originally Posted by hands

Yes, I have split Trane and Carrier coils many times. But on the 20 ton Trane RTU's I have worked on, the coils can't be split. I havn't checked the 30 ton unit I have been talking about because you have to lift the top to see how the coil is made.

Have you been able to split coils on 30 ton Trane Voyager's. The Model number is #YCD360A4HK1A2DH1ABC00F0H00000.

I've done 301's and have heard about the 360's and 420's. Me thinks super fitter tech must know something about it.

Originally Posted by Dallas Duster

Have you ever split a Trane coil Hands?

Yes, I have split Trane and Carrier coils many times. But on the 20 ton Trane RTU's I have worked on, the coils can't be split. I havn't checked the 30 ton unit I have been talking about because you have to lift the top to see how the coil is made.

Have you been able to split coils on 30 ton Trane Voyager's. The Model number is #YCD360A4HK1A2DH1ABC00F0H00000.

Originally Posted by hands

Sorry for the delay, I just got back from vacation.

Six- The fans are pinwheeling, if one fans is on, the other two pinwheel, but not real fast so the 2nd fan can overcome it when it starts. When two fans are running, the 3rd is pinwheeling fast and then runs back wards. The schematic shows four fans but has a small insert for three fans, but not all of the wire numbers match. Trane likes to do this for some reason.

gwoner-The k4 relay is not welded shut, I had to jump it at times to get the fan to run.

superfittertech- It is a two coil condenser, not sure if they can be split. You would four guys or a crane to get the top off. But if it is like the 20 ton units, the coil can't be split.

Have you ever split a Trane coil Hands?

Sorry for the delay, I just got back from vacation.

Six- The fans are pinwheeling, if one fans is on, the other two pinwheel, but not real fast so the 2nd fan can overcome it when it starts. When two fans are running, the 3rd is pinwheeling fast and then runs back wards. The schematic shows four fans but has a small insert for three fans, but not all of the wire numbers match. Trane likes to do this for some reason.

gwoner-The k4 relay is not welded shut, I had to jump it at times to get the fan to run.

superfittertech- It is a two coil condenser, not sure if they can be split. You would four guys or a crane to get the top off. But if it is like the 20 ton units, the coil can't be split.

Real fun to clean.

those are triple split coils

fans

check the k4 relay . I bet your contacts are welded closed.

Don't you have to split those coils also?

If two fans are spinning backwards its most likely because they're pinwheeling.

Air running through the blades spinning them backwards.

If they're getting power to a leg on the motor when they shouldnt then someone monkeyed with the wiring and it needs to be repaired.

Should be a schematic you can refer to.