Advanced Refrigeration Podcast

EVEN More CO2 Blast Freezers, How A Subcooler Can Affect Compressor Capacity - Episode - 545Trapped Oil, Wild Suction Swings & the Subcooler That Won’t Behave | Advanced Refrigeration Podcast. In this episode of the Advanced Refrigeration Podcast, hosts Brett Wetzel and Kevin Compass bounce from shop talk about Kevin’s four-screen setup to a blast-freezer mystery update: roughly 15 gallons of oil were found trapped in the flooded evaporator, sparking manufacturer finger-pointing and discussion of oil drain strategies, PAG oil behavior at very low temps, and why an economizer may not work without a pressure differential or pump. Kevin also recaps a brutal Alaska trip fixing coils shipped with undersized TXVs that caused high superheat and poor pull-down. The main deep dive tackles an A2L rack with a subcooler and crossover control, where a too-low suction/EPR setting drives the subcooler to short-cycle, alters vapor injection, and creates extreme, rapid suction pressure swings—making the crossover valve inconsistent and the system nearly impossible to stabilize.

EVEN More CO2 Blast Freezers, How A Subcooler Can Affect Compressor Capacity - Episode - 545Trapped Oil, Wild Suction Swings & the Subcooler That Won’t Behave | Advanced Refrigeration Podcast. In this episode of the Advanced Refrigeration Podcast, hosts Brett Wetzel and Kevin Compass bounce from shop talk about Kevin’s four-screen setup to a blast-freezer mystery update: roughly 15 gallons of oil were found trapped in the flooded evaporator, sparking manufacturer finger-pointing and discussion of oil drain strategies, PAG oil behavior at very low temps, and why an economizer may not work without a pressure differential or pump. Kevin also recaps a brutal Alaska trip fixing coils shipped with undersized TXVs that caused high superheat and poor pull-down. The main deep dive tackles an A2L rack with a subcooler and crossover control, where a too-low suction/EPR setting drives the subcooler to short-cycle, alters vapor injection, and creates extreme, rapid suction pressure swings—making the crossover valve inconsistent and the system nearly impossible to stabilize.

More CO2 Blast Freezers And WTH Is A Surge Drum, & What About MASS FLOW ?? Episode - 544CO₂ Rack Startup From Hell: ICAD Firmware Resets, Allen-Bradley Pain, and 20 Gallons of Missing Oil On the Advanced Refrigeration Podcast, hosts Brett Wetzel and Kevin Compass unpack a miserable CO₂ spiral freezer rack startup that ran long, went sideways, and left one host stranded with one T-shirt and dwindling underwear. A blast freezer startup rep moved painfully slow, firmware updates on ICAD B controllers reset passwords to all zeros, and time was lost fighting a remote engineer over 20 mA feedback that pegged valves open. After finally starting the rack, they hit a major oil return problem—roughly 20 gallons added with little coming back—suspecting oil logging in the freezer’s liquid vapor separator/surge drum, possibly worsened as temperatures dropped to around -43°F suction. They review the rack’s piping (desuperheater, gas cooler, flash tank, heat exchangers, accumulator drain logic) and debate causes like separator sizing, violent vessel behavior, and the need for an oil return/skimmer-style cycle before product loads arrive.

More CO2 Blast Freezers And WTH Is A Surge Drum, & What About MASS FLOW ?? Episode - 544CO₂ Rack Startup From Hell: ICAD Firmware Resets, Allen-Bradley Pain, and 20 Gallons of Missing Oil On the Advanced Refrigeration Podcast, hosts Brett Wetzel and Kevin Compass unpack a miserable CO₂ spiral freezer rack startup that ran long, went sideways, and left one host stranded with one T-shirt and dwindling underwear. A blast freezer startup rep moved painfully slow, firmware updates on ICAD B controllers reset passwords to all zeros, and time was lost fighting a remote engineer over 20 mA feedback that pegged valves open. After finally starting the rack, they hit a major oil return problem—roughly 20 gallons added with little coming back—suspecting oil logging in the freezer’s liquid vapor separator/surge drum, possibly worsened as temperatures dropped to around -43°F suction. They review the rack’s piping (desuperheater, gas cooler, flash tank, heat exchangers, accumulator drain logic) and debate causes like separator sizing, violent vessel behavior, and the need for an oil return/skimmer-style cycle before product loads arrive.

Blast Freezer Convo, & A Loop Sequencer For EPR Control, And A Cross Over ?? Episode - 543CO2 Blast Freezer Startup Chaos + Taming Load-Shed Valves (PID Tuning Without Losing Your Mind)In this episode of the Advanced Refrigeration Podcast, Brett and Kevin recap a CO2 blast freezer rack startup in Minnesota, including a pump-down system with a flash tank setup and a 45-bar-rated rack that sparked questions. The startup went sideways when an oil reservoir appeared empty, oil was pumped in, a compressor kicked on unexpectedly, hydraulically hammered the high-pressure switch, and blew the compressor relief—spraying oil on Brett—after a TechLab relay locked the oil fill on. They then shift to ongoing work: dual-temp HFC island case startups and troubleshooting an underloaded low-temp rack that short-cycles compressors. Kevin shows how a CDS valve on a loop sequencer was hunting from 0–100% and how reducing P gain stabilized suction, then they discuss load shedding/crossover valves, energy tradeoffs, and practical PID tuning tips like filtering, throttle range, direct vs reverse action, and making one change at a time.

Blast Freezer Convo, & A Loop Sequencer For EPR Control, And A Cross Over ?? Episode - 543CO2 Blast Freezer Startup Chaos + Taming Load-Shed Valves (PID Tuning Without Losing Your Mind)In this episode of the Advanced Refrigeration Podcast, Brett and Kevin recap a CO2 blast freezer rack startup in Minnesota, including a pump-down system with a flash tank setup and a 45-bar-rated rack that sparked questions. The startup went sideways when an oil reservoir appeared empty, oil was pumped in, a compressor kicked on unexpectedly, hydraulically hammered the high-pressure switch, and blew the compressor relief—spraying oil on Brett—after a TechLab relay locked the oil fill on. They then shift to ongoing work: dual-temp HFC island case startups and troubleshooting an underloaded low-temp rack that short-cycles compressors. Kevin shows how a CDS valve on a loop sequencer was hunting from 0–100% and how reducing P gain stabilized suction, then they discuss load shedding/crossover valves, energy tradeoffs, and practical PID tuning tips like filtering, throttle range, direct vs reverse action, and making one change at a time.

Flexible Combiners, CO2, SH, Liquid Injection, & Hotgas.. Anti Relief, and Oil Control Episode 542CO2 Rack Chaos: Superheat Mitigation, Anti-Relief Headaches & Flex Combiner FailsBrett Wetzel and Kevin Compass catch up on a hectic pre-Thanksgiving workload, including MicroThermal programming surges, Walmart K2 case startups with inconsistent wiring, and struggles accessing newer Novar controllers due to password and tech support issues. They then walk through CO2 rack control logic using E3 flexible combiners, focusing on hot gas injection superheat mitigation, debating appropriate superheat cut-in/cut-out and how low superheat worsens oil carryover. They critique an anti-relief strategy near the flash tank for causing flat racks via dry ice sticking valves, and discuss a receiver hot gas injection scheme meant to maintain winter receiver pressure and oil differential, noting an apparent incomplete implementation. They also review overly complex oil separator pulsing logic, relay wear concerns, and argue standardized CO2 suction group control could eliminate much custom programming confusion

Flexible Combiners, CO2, SH, Liquid Injection, & Hotgas.. Anti Relief, and Oil Control Episode 542CO2 Rack Chaos: Superheat Mitigation, Anti-Relief Headaches & Flex Combiner FailsBrett Wetzel and Kevin Compass catch up on a hectic pre-Thanksgiving workload, including MicroThermal programming surges, Walmart K2 case startups with inconsistent wiring, and struggles accessing newer Novar controllers due to password and tech support issues. They then walk through CO2 rack control logic using E3 flexible combiners, focusing on hot gas injection superheat mitigation, debating appropriate superheat cut-in/cut-out and how low superheat worsens oil carryover. They critique an anti-relief strategy near the flash tank for causing flat racks via dry ice sticking valves, and discuss a receiver hot gas injection scheme meant to maintain winter receiver pressure and oil differential, noting an apparent incomplete implementation. They also review overly complex oil separator pulsing logic, relay wear concerns, and argue standardized CO2 suction group control could eliminate much custom programming confusion

Flexible Combiners In E3, What Are They, And Some Rae Corp Shenanigans Episode 541Flexible Combiner 101 (E2/E3): Stop Blaming the Flexie for EverythingOn the Advanced Refrigeration podcast, Brett Wetzel and Kevin Compass start by troubleshooting a Raycorp CO2 skid startup where one pump won’t make differential despite drive and check-valve checks, concluding the pump is likely bad and difficult to replace due to skid framing and serviceability constraints. They then shift to a practical walkthrough of programming Copeland E2/E3/Site Supervisor “flexible combiners,” emphasizing that flexies are open applications and many tasks should use simpler sensor controls instead. They stress labeling inputs/outputs, using E3 tools like duplicate tabs for troubleshooting, lowering update time for testing, and avoiding common syntax/type errors. They demonstrate building a timer, a cut-in/cut-out fan control (including averaging sensors), and a leak-detector shutdown using if statements and network variable targets, recommending the flexible combiner programming supplement as a reference.

Flexible Combiners In E3, What Are They, And Some Rae Corp Shenanigans Episode 541Flexible Combiner 101 (E2/E3): Stop Blaming the Flexie for EverythingOn the Advanced Refrigeration podcast, Brett Wetzel and Kevin Compass start by troubleshooting a Raycorp CO2 skid startup where one pump won’t make differential despite drive and check-valve checks, concluding the pump is likely bad and difficult to replace due to skid framing and serviceability constraints. They then shift to a practical walkthrough of programming Copeland E2/E3/Site Supervisor “flexible combiners,” emphasizing that flexies are open applications and many tasks should use simpler sensor controls instead. They stress labeling inputs/outputs, using E3 tools like duplicate tabs for troubleshooting, lowering update time for testing, and avoiding common syntax/type errors. They demonstrate building a timer, a cut-in/cut-out fan control (including averaging sensors), and a leak-detector shutdown using if statements and network variable targets, recommending the flexible combiner programming supplement as a reference.