Learn more about Refrigeration Mentor Customized Technical Training Programs at www.refrigerationmentor.com/courses

Join the Refrigeration Mentor Hub here

This is the second of a 2-part episode in our "CO2 Unfiltered" series where we're joined by Massimo Pellizzari, Senior Commissioning Engineer at Daikin, for an in-depth look at Daikin's two-stage CO2 condensing units (link to Part 1 below). Here, we cover wiring, as well as troubleshooting via the onboard display and buttons, alarm code structure, and conditions like wet operation, high-pressure switch trips, and how the controller can detect overcharge or refrigerant shortage. This 2-part episode is packed with practical insights to help technicians work more faster and more confidently with CO2 condensing units.

(00:36) Power Supply Wiring Basics

(05:44) High Pressure Switch Cutout

(07:07) Reading Alarm Codes

(08:38) Wet Operation and Superheat

(14:21) Expansion Valves for High Pressure

(17:50) Piping Diagram and Valve Locations

(19:49) Subcooling Charts and Charge Errors

(23:40) Recovering or Adding Charge Safely

(26:17) Service Access Basics

(27:56) Backup Modes

(31:44) Setpoints and DIP Switches

(33:52) Piping Logic and P&ID

(37:22) Isolating and Purging CO2

(39:45) Oil Loss and Recharging

(40:55) Valve and Sensor Diagnostics

(47:33) Install Tips and Cleanliness

Helpful Links & Resources:

Massimo in LinkedIn

Daikin

PART 1: Episode 418. Daikin 2-Stage CO2 Condensing Unit Servicing and Troubleshooting with Massimo Pellizzari (Part 1)

Episode 14. What About Condensers in Refrigeration Applications?

Episode 394. Condensing Unit Checkpoints

Learn more about Refrigeration Mentor Customized Technical Training Programs at www.refrigerationmentor.com/courses

Join the Refrigeration Mentor Hub here

This is the first of a 2-part episode in our "CO2 Unfiltered" series covering what causes compressor failures and how to prevent them, featuring Jonas Linnemann, Vice President of Technology at Vitalis. Jonas explains why oil return is more challenging in CO2, and covers topics like primary vs secondary oil circuits, separator efficiency and compressor oil carryover. He also shares practical service and maintenance tips that will help refrigeration techs prevent recurring compressor failures.

In this episode, we discuss:

(01:34) Why Oil Management Matters

(03:34) Booster System Basics

(04:47) Common Oil Misconceptions

(09:20) Viscosity and CO2 Solubility

(15:21) Primary vs Secondary Oil Circuit

(19:59) Reading P&IDs

(23:16) Oil Return Overview

(24:57) Strainers and Maintenance

(27:19) CO2 Separator Cartridges

(29:03) Differential Pressure Checks

(32:39) Oil Carryover Troubleshooting

(36:40) Cartridge Blowout Warning Signs

(40:57) Contamination in Regulators

(44:34) Cartridge Change Procedure

(47:35) Evacuation and O-Ring Tips

Helpful Links & Resources:

Jonas on LinkedIn

Vitalis

Episode 390. CO2 Oil Management (Part 1): Lubrication Basics, Oil Selection, Testing, and Troubleshooting with Alessandro Silva of Bitzer

Episode 330. Oil Issues in Refrigeration Systems

Episode 124: CO2 System Oil Management: Insights from Adam Chapman of Westermeyer Industries

Learn more about Refrigeration Mentor Customized Technical Training Programs at www.refrigerationmentor.com/courses

Join the Refrigeration Mentor Hub here

In this episode, we're reviewing a recent field story from inside the Refrigeration Mentor Community of handling a "compressor proof/safety failure" alarm. Upon arrival, the compressor was running. But instead of assuming a nuisance trip, this episode walks through how confirm the cause of issue by running diagnostics using free manufacturer software (Copeland CoreSense). Being able to accurately to validate findings builds technician confidence, speeds up troubleshooting time and helps prevent future costly failures.

In this episode, we discuss:

(00:48) Compressor Trip Alarms

(02:23) Copeland CoreSense Basics

(04:02) Laptop and Cable Setup

(05:42) Connection Pain Points

(07:09) Fixing the Wiring

(08:42) How Validation Builds Confidence

(10:19) Refrigeration Troubleshooting Skills

Helpful Links & Resources:

Website: Copeland CoreSense

Episode 378. Field Stories: Compressor Failure, Case Freeze-Up Troubleshooting, and Electrical Safety

Episode 295. A Compressor Story: The Key to Faster Troubleshooting