Trane control problem


  #1  
Old 08-02-08, 04:53 AM
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Trane control problem

Working on Trane Precedent Mod wsc090a3rga2d00.
The cond fan will run, but no power to the comp contactor. HP and Lp contacts are closed and reliatel board has been changed out. Still won,t run. Tech has comp picked up by paralleling its contactor coil with the cond fan relay coil signal. No power on reliatel output pin to cc1.
Any clue to what might be wrong?
 
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Old 08-02-08, 06:47 AM
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7 1/2 tons is large for residential.

First question for you here is, Did it work in test mode?

Second is, do you have the books?

Reliatel, like Voyager controls, can be a pain to t-shoot with out the detailed Trane books.

Since you've changed the board and still have the same problem, it's probably not that. Beware of parts changers.

Here is a quick check if the unit has an Economiser. In the blower compartment is a large (white) molex plug to the economizer, disconnect it and see if your compressor works.

If that works, will explain later.
 
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Old 08-02-08, 12:05 PM
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Test failed to energize unit.
No economizer.
No books, only a poor control schematic.
Found out in the meantime that the cond fan and comp are hot wired for the weekend.
Sure could use any suggestions that you may have to offer. Tom
 
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Old 08-02-08, 02:11 PM
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WooHoo! A problem we can sink our teeth into. The hard ones are always the most fun and best teachers.

Could then be (maybe) the fan proven switch, filter switch, RTOM board, and more.

Follow instructions in PM, I have books and troubleshooting guides for ReliaTel to forward.

May or may not help, but if you have the unit serial number, I maybe able to see what options the beast in question came with. Which could narrow down things to check.

Basically, since the comp contactor will not energize in test mode, something is telling the RTRM it is not safe to turn on the compressor.

All the "boards" in these units are really little "computers" that "talk" to each other. Which is why I suggested to unplug the economizer. Most likly culprit not talking to anyone.

Oh, everything I have to forward is at least 4Mb, if your email can't handle it I can post on a website for download. Wiring book covers all WSC units and all voltages and is 4Mb.

So, lets see how best to skin this cat.
 
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Old 08-03-08, 01:08 PM
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Whoa Nellie!

Tom,

I've had some time during my yardwork break to look more at the issue at hand.

It is impossable, assuming no one has rewired the controls in this unit, for the condenser fan to operate without the compressor contactor closed.

True, the unit does have an Outdoor Fan Relay that is controlled by the RTRM. The ODF relay breaks one line to the fan motor. Wire 12A (violet) runs to the fan capacitor and on to the fan.

BUT! The other leg to the fan is from the Comppressor Contactor. Meaning that without the compressor contactor pulled in the outdoor fan will not, cannot operate.

I hate to say it my friend, but I think if we are going to skin this cat You will need to go out there yourself and verify just what is really going on.
 
 

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