TCI Module Comm Failure

Issue:

TCI Module Comm Failure

Resolution:

• This diagnostic means that the TCI Module (1U54) is not communicating with Cold Generator Module (CGM,  1U48).  
• The cause for this can be as follows:
  a) wiring error
  b) defective TCI or
  c) no control power to TCI. 
• All the modules share a communication link using twisted wire.  
• The J1 connector on each module is the connection point for this communication link.  They all connect to a common point on the 1TB9 terminal strip mounted over the CGM.  The comm link is polarity sensitive.

Here are the steps for Intellipak Air-Cooled Chiller

Step #1 Wiring Error

• Verify proper wiring between TCI (1U54) J1 connector to 1TB9 and CGM to 1TB9.  
• Refer to unit wiring diagram control box door for wire numbers and connection points.  
• Check for good connections (no open circuits or shorts to ground) and proper polarity.  
• If no errors are found, proceed to Step 2.

Step #2 Control Power

• If the TCI (1U54) does not have 24 VAC, this diagnostic will be generated.  
• Check for 24 VAC at J2 on the TCI.  
• There are two control power transformers for the modules in the unit.  
• They have a circuit breaker on the secondary.  
• The CGM (1U48) and the Human Interface (1U65) are one the same transformer.  It is possible for them to be powered but other modules not have power. 
• If 24 VAC is not present, check wiring.  
• Refer to unit schematics on the control box door.  
• If 24 VAC is present at J2, continue below.

Step #3 Control Module

• Verify that the DIP switch settings are correct.  
• For Comm 3 communication, all DIP switches should be OFF. 
• Disconnect unit power.  
• Unplug all connectors except J1 and J2 on the TCI.  
• Restore unit power.  
• If communications are restored, check module wiring per unit schematics. 
• If communications are not restored, replace TCI.  
• If possible verify defective TCI by exchanging with a TCI from another unit.

Facts:

• Intellipak Air-Cooled Chiller 20-60