Failed Discharge Pipe and Valve RTAC

Issue:

Discharge Line Failure, Discharge Valve Failure, Compressor Failure, due to off-cycle refrigerant migration or refrigerant pooling in the discharge line of "OFF" compressors.

Resolution:

RTAC:  Identify your specific design sequence below to make sure you select the correct components required for the specific chiller vintage.  ALL Discharge Lines, Valves, etc. that have failed MUST BE REPLACED...NO SCAB REPAIR.

"A0 - V0" ONLY - Design Sequence: (model number digits 10 , 11)

• KIT12479 contains the complete Discharge Line from the "B" Compressor to the Oil Separator, on either circuit. All components will be brazed here at the factory and shipped as a single component to the field.
  • KIT12479 is the piping for the "B" compressor to the oil separator for each circuit. KIT12479 includes everything that is in KIT09681 (discontinued) plus the large tube going to the oil separator. There is no pipe that goes from the tee to the opposite side, "A" compressor. There is no drawing of KIT12479. The tube that goes to the opposite side, "A" compressor is not available and will need to be secured locally. The pipe is 3.125 OD pipe. The parts listed below in KIT12479 are the parts used to go from the compressor flange FLG00598, to the bushing BUS00870, to the elbow ELL00936, to the 3.125 pipe (TUBE; 3.12 OD X 0.09W CU S (qty 13.79"), to the Tee TEE00873 , to the 4.125 inch tube (TUBE; 4.12 OD X 0.110W CU ( qty 37.97") , which will connect to the oil separator.

• KIT12479 contents:

1. FLG00598 (qty 1)
2. BUS00870 (qty 1)
3. ELL00936 (qty 1)
4. TUBE; 3.12 OD X 0.09W CU S (qty 13.79") This is the tube with a slight bend
5. TEE00873 (qty 1)
6. TUBE; 4.12 OD X 0.110W CU ( qty 37.97")

• There is a weight or a support Discharge line weight that should be added to the 4-1/8  OD line between the tee and the oil separator; Trane Part Number: SUP04764. Newer units ship with this part (therefore may already be present).
  • Note:  ALL LAC RTAC chillers built after 3rd quarter 2004 will have the weight installed.
  • Note: ALL LAC RTAC chillers "W0" Design Sequence and Later will no longer have this weight.

• Additional:
  • Ensure weight is installed on the discharge line 1/2 the distance between the Oil Separator and the "T" fitting.
    • See note above for important date and design sequence information.
  • To avoid repeat failure, it will be necessary to ADD a Normally Closed Solenoid Valve to the Sludge Line (Oil Return from the bottom of the Evaporator, to the belly of each Compressor). To control the solenoid valve(s), a relay will be added between a respective compressors Starter LLID and neutral.
• Required wiring change/Modification:
  • For each circuit with manifolded compressors; between each compressor Starter LLID/module and neutral, NEW Solenoid Valve/Coils will be wired between J10-1 and neutral.  For current production chiller the designators...Circuit 1 - 3L7 and 3L8 for 3 & 4 compressor chillers; and Circuit 2 - 4L7 and 4L8 for 4 compressor chillers.
  • This means, for example...circuit 1 has 1U14 and 1U19 Starter LLIDs. There will be a new solenoid valve coil added for each compressor starter LLID/module.
  • For each circuit with manifolded compressors; there will be piped in, a Normally Closed - NC Valve; SOLENOID 0.38 ODS, one for each compressor Sludge Line (Oil Return Line) to reduce off-cycle migration, which can result in a compressor starting with liquid in it...which is a known contributor to Discharge Line/Valve Failure. X13320962010 (NC valve  VAL07078). [Normally Closed - NC Valve; SOLENOID 0.38 ODS], this is a standard 3/8-NC solenoid valve with a 120VAC coil. Coil PN for listed valve: COL03780. This solenoid valve will be physically located after the strainer/filter in the piping.  ( Note: See wiring diagram below or attached .pdf file for reference. )
  • Wiring reference example:

Mechanical change, design sequence A0 - V0:

•  3/8” copper to be field provided.  Soft copper can be used if desired.
• The fittings go into the bottom of each compressor in the PLUG location near the Sludge Line Evaporator Oil Return Connection.
• The valve (angle valve) is for service; and should remain open for normal circuit operation.

• Fittings Required Per Circuit:  (these are new cross-over fittings for manifolded compressors, Circuit 1 on a 3 compressor chiller)
• or
• Fittings Required Per Circuit:  (these are new cross-over fittings for manifolded compressors, Circuit 1 & 2 on a 4 compressor chiller)

"W0 - present" - Design Sequence: (model number digits 10 , 11)

The Discharge Line KIT set up below is the same for either Circuit 1 or Circuit 2; Compressor 1A, 1B, 2A, or 2B.  The KIT comes assembled, however the parts are listed below for reference:

• KIT16845 - Compressor Discharge Line & Valve:

  • 1420        X15091192010 -  BUS00870 - REDUCER;3.12OD VLV ASSY

  • 1421        X15090668010 -  CLR00057 - COLLAR; FLANGE, VALVE, COMPRESSOR

  • 1422        572247380100 -  TUB13355 - TUBE; DISCHARGE LINE W/90 DEGREE ELBOW

  • 1423        X15330623010 -  VAL10444 -  VALVE; BALL VALVE, 3.125, FULL PORT

For reference, this is the Discharge Line Assembly:

Required wiring change for design sequence "W0 - Z0"  -  3 or 4 compressor chillers:

• None REQUIRED for first time failures
• If the chiller has previously been modified electrically for this issue (sludge line solenoid valve rewire); the chiller needs to be returned back to original factory wiring, removing the solenoid valve rewire.  (See chiller original wiring diagram for reference.)

Required wiring change for design sequence "1A - present" -  3 or 4 compressor chillers:

• Solenoid Valve Control wiring Modification:  REMOVE W11 Jumper in each Starter Panel

Mechanical change, design sequence W0 to present:

•  3/8” copper to be field provided.  Soft copper can be used if desired.
• The fittings go into the bottom of each compressor in the PLUG location near the Sludge Line Evaporator Oil Return Connection.
• The valve (angle valve) is for service; and should remain open for normal circuit operation.

• Fittings Required Per Circuit:  (these are new cross-over fittings for manifolded compressors, Circuit 1 on a 3 compressor chiller)
• or
• Fittings Required Per Circuit:  (these are new cross-over fittings for manifolded compressors, Circuit 1 & 2 on a 4 compressor chiller)

Example - Failed Discharge Line

Notes:

• Please have the local Trane Parts Department verify the part number based of off the Design Sequence before ordering the Discharge Line Kit.
• ALL Discharge Failures need to have the failed discharge lines, valves, piping replaced to ensure on-going reliability.  DO NOT ACCEPT A SCAB REPAIR

Changes:

Other Question/Problem/Cause Statements:

• Discharge Line Failure?
• Cracked Discharge Line?
• Repeat Failure of Discharge Line?
• Oil Return Line Modification?
• Oil Scavenger Line Modification?
• Is there a discharge line repair kit?
• RTAC manifolded discharge line cracked?
• KIT09681?
• KIT12479?

Facts:

• Air-Cooled Chiller (Pueblo) (RTAC)