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

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

Join the Refrigeration Mentor Hub here

In this episode, I'm sharing some of the tips, resources and materials refrigerators should be checking out to learn refrigeration faster. These tips and resources need to be utilized both on that job and after work, things like manuals, processes, checklists, and investing in additional training after hours. We'll also discuss documenting service call steps, reviewing for missing details, and using on site data AI to refine concise checklists and get to the root of issues. These are the keys that the best techs use to stop guessing on service calls and solve issues faster and more confidently.

In this episode, we cover:

(01:51) Writing Things Down to Learn

(02:43) Repetition Builds Mastery

(03:14) CO2 Procedures Step by Step

(05:16 Teaching Like a Mentor

(07:08) Building A Framework for Any System

(08:55) Using AI in Refrigeration

(09:57) Knowing Normal Data

(11:20) Building Habits That Stick

Helpful Links & Resources:

BOOK: Atomic Habits by James Clear

Episode 413. My 4-Pillar Framework to Learn CO2 Refrigeration Faster

Episode 288. The Payoff of Investing Time & Money in Training with Jesse Stewart

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 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. Massimo explains the design philosophy behind these systems, how they differ from traditional refrigeration equipment and the best practices for installation, commissioning, evacuation, charging and servicing. Whether you're new to CO2 or looking to sharpen your troubleshooting skills, this episode is packed with practical insights to help technicians work more faster and more confidently with CO2 condensing units.

In this episode, we discuss:

(03:10) Why CO2 condensing units are becoming more common worldwide

(05:30) Daikin's two-stage CO2 condensing unit lineup

(07:15) Swing compressor technology and compressor design

(09:45) Oil in CO2 systems

(11:45) Two-stage compression and reducing discharge temperatures

(17:30) Controller features, monitoring and diagnostics

(24:00) Refrigerant charge calculations and piping design software

(33:30) Factory testing, vibration protection and installation considerations

(38:30) Service valves, access points and system maintenance

(49:30) Pressure testing and evacuation procedures

(50:55) Opening EEVs and solenoid valves during evacuation

(51:00) Refrigeration-grade CO2 and refrigerant purity

(53:10) Proper CO2 charging procedures and overcoming the triple point

(57:30) Service ports, valve design and final technician tips

Helpful Links & Resources:

Massimo in LinkedIn

Daikin

Episode 414. Breaking the Stigma and Learning to Love CO2

Episode 180: Developing your CO2 Knowledge into Experience

Episode 146: CO2 Technical Training with Brett Wetzel

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 talking about changing oil separators on a CO2 supermarket system. THis conversation stems from a recent field story from a fellow tech where the separator outlet valve kept leaking after pressure was relieved. We'll discuss the process for fixing the issue safely, and how this type of learning through community knowledge-sharing and continuing education is so important for all refrigeration technicians new and old to troubleshoot faster and more confidently. Want to join the next Refrigeration Community Meetup live? Click here to join free!

In this episode, we cover:

(02:20) Oil Separator Valve Fix

(02:59) Pressure Reversal Explained

(06:09) Why Mentorship Matters

(06:46) Refrigeration Career Path Tips

(07:28) Refrigeration Safety

Helpful Links & Resources:

Episode 330. Oil Issues in Refrigeration Systems

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

Episode 71. Top Tips For Learning CO2 Refrigeration

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

Join the Refrigeration Mentor Hub here

This episode includes highlights from a recent live Refrigeration Mentor Community meetup where we covered real-world CO2 rack issues, system tuning, troubleshooting, and startup strategies, sharing practical techniques we've learned in the field. We covered gas cooler fan tuning, transcritical operation, oil separator maintenance and service valve tips. This meetup featured experienced CO2 technicians Patrick Gregory, Noah Walker, Andrew Freeburg, Billy Carlson and others sharing valuable insights that can help fellow technicians diagnose problems faster, improve system performance, and learn from the experience of others.

In this episode, we discuss:

(02:15) Fine-tuning CO2 racks

(05:20) Gas cooler fan control strategies

(09:00) Rack tuning

(12:00) Why every CO2 system requires its own tuning strategy

(16:00) Oil separator filter replacement and diagnosing oil trip issues

(18:00) Proper rack pump-down procedures

(20:00) Service valve troubleshooting

(23:45) Common ball valve issues

Helpful Links & Resources:

Episode 382. Why Techs Get Stumped on Supermarket Racks (How To Fix It)

Episode 250. Service Call Stories and Troubleshooting Tips with Andrew Freeburg

Episode 163. A Pro's Handbook for Effective Refrigeration Troubleshooting