from the editor ... This newsletter was originally published in December 1998. We reviewed and updated its content to complement an Engineers Newsletter Live telecast, which airs on December 5, 2001.

The efficiency and reliability of an R-22, split air-conditioning system hinges largely on the piping that connects the refrigerant-condensing and air-handling sides of the system. Operational difficulties are inevitable if this interconnecting piping is improperly designed or installed, regardless of how carefully the equipment was selected and applied.

Interconnecting piping designs that successfully avoid these difficulties share several common traits:

• A simple, direct layout that reduces the amount of system refrigerant.

• A refrigerant tube size that consistently returns oil to the compressors.

• A refrigerant tube size that doesn't cause excessive pressure drops which reduce compressor efficiency and capacity.

Some of the piping techniques discussed in this newsletter wouldn't have been considered good practice in the past, but they work best and most reliably for modern commercial Trane equipment with scroll compressors.

This Engineers Newsletter previews the selection and refrigerant piping guidelines now recommended for Trane's current line of commercial split-system/scroll-compressor equipment.

Table of Contents

• Equipment Selection
• Interconnecting Piping
• Bottom Line...