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EXV Electrical Drive Fault Diagnostic RTAA/UA/WA

Updated

Issue:

EXV Electric Drive Diagnostics

 

Resolution:

 

RTAA/UA/WA Packaged Chillers:

  • If you experience EXV Drive Failure Diagnostics on "packaged" units, follow the steps in RTAA-SB-5 (130-400) or RLC-SVD03A-EN (70-125)

 

RTAA Remote Evaporators

  • These chillers have certain requirements for the wires between the control panel and the expansion valve terminal block
  • See the appropriate IOM for specifications
  • Wires must be at least 16 ga
  • Wire that is too small will result in EXV drive failure diagnostics
  • Try taking the wires from one circuit and "stacking" them on the other to reduce impedance
    • If the diagnostics stop, or continue to be intermittent, you have found your problem and should replace wires between the EXV and control panel

 

New Style SEHI EXV & Module:

  • The SEO style EXV has been replaced with SEHI style valves
  • The two are not compatible with each other and require all EXV valves and EXV Module(s) to be replaced
  • The original valve was a three winding valve, while the SEHI valve has two windings (Red-Green & White-Black) which should be 70-75 ohms
  • The wire connections of the new valve to the new module are different. Below are the correct wire connections:

 

 

 

       

 

 

Notes:

  • EXV Module X13651064 must be revision -040 (Rev D) or newer to avoid intermittent operational issues.  
  • Current module revision = H
  • Minimum software revision 6200-0326-07
    • Latest revision -08
  • There is no longer an issue with Neodymium motors provided minimum module revision is present as shown above.

Resource Available:

 

Other Question/Problem/Cause Statements:

  • EXV Elec. Drive Ckt - Rfgt Ckt 1?
  • EXV Elec. Drive Ckt - Rfgt Ckt 2?
  • EXV Electrical Drive Fault?

 

Facts:

  • Air-Cooled Chiller RTAA 70-125 Ton
  • Air-Cooled Chiller RTAA 130-400 Ton 

 

Document Identifier: DOC-80715

 

WARNING:

Information in this article is intended for use by individuals possessing adequate backgrounds of electrical and mechanical experience and who comply with all federal, state, and local laws, rules, orders, or regulations related to the installation, service, or repair of a heating or central air conditioning product. Any attempt to install, service, or repair a heating or central air conditioning product may result in personal injury and/or property damage. The manufacturer or seller cannot be responsible for the interpretation of the information contained herein, nor can it assume any liability in connection with its use.

 

 

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