Expansion Valve replacement of Trane & Freon - http://www.hvacmechanic.com/ Forums
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| TnNATE1412
 |  "Re(1):Expansion Valve replacement of Trane & "
, posted Fri 18 Jul 21:30  
From the R.E. Michel Website:
Servicing A/C & Heat Pump & Refrig. Units "Opened to Atmosphere"
Standard practices when servicing a system that has been "open to atmosphere" REQUIRES three steps be included in the overall service procedures. However, it appears that many times these steps are being bypassed, or forgotten during the service call.
(This applies anytime a system has been serviced to fix a leak, replace a compressor, or replace any component in the sealed refrigeration system.)
1. Replace the drier. ( DO NOT leave the original drier in side the unit. It is contaminated and MUST be removed. It cannot be decontaminated thru evacuation)
2. Perform an acid test. Not just when a burned compressor is confirmed. Sometimes enough oil may be drained from the removed drier to do the acid test.
3. Perform a pressure and vacuum leak check to assure the system is leak free before recharging. Evacuate to at least 500 microns for moisture removal and vacuum leak check.
Obviously these steps should be part of any service call when a system is opened. More often than not one or more of these steps are not performed! If they were, we would see a dramatic reduction in instances involving repeat compressor failures.
So... whenever you detect a leak in a system, or expecially when replacing a compressor, be sure to include the 3 steps above. Use Michel Cat # 4G9605, 6R077, or 8R090 acid test kits and the appropriate Alco, Parker, or Sporland drier for the job.
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| pbreazeale
|  "Re(1):Expansion Valve replacement of Trane & "
, posted Thu 17 Jul 22:06
NO, freon should have been pumped down into the compressor, lines leak checked, pulled into a vacuum, freon released back into system, and a nominal amount, enough to refill line set and evaporator coil used.
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| TnNATE1412
| "Re(1):Expansion Valve replacement of Trane & " , posted Thu 17 Jul 19:38
To do the job right the first time, the filter-drier needs to be replaced in the outdoor unit, and YES the refrigerant would need to be replaced. You can do things the cheap way and pump the charge back into the outdoor unit (if it's a split system), leave the old drier in, replace the part, evacuate and release the charge. Then sit back and wait for the next phone call from you that the system don't work again to charge you again.
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| mississippi
| "Re(1):Expansion Valve replacement of Trane & " , posted Thu 17 Jul 14:38
they should be able to pump system down replace valve,pull vacuum and return refrigerant without losing any
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