On this episode of the Advanced Refrigeration Podcast, hosts Brett Wetzel and Kevin Compass welcome new sponsor NDL Industries with guests Lucas (a Lithuania-based product manager with CO₂ rack design experience) and Amit (VP of Sales in Austin). They discuss the rapid growth of CO₂ refrigeration driven by regulations and efficiency improvements like parallel compression and ejectors, and the need for readily available parts—highlighting NDL’s US distribution hub near Memphis and 130 bar UL-rated fittings. The conversation digs into CO₂ valve and check-valve ratings (UL vs CRN testing), actuator torque challenges, and NDL’s upcoming motorized three-way valve with clearer positioning and positive stops. They also cover service valve/Service-T design to reduce brazed joints, plus real-world transcritical heat reclaim behavior and gas cooler sizing and climate impacts.

On this episode of the Advanced Refrigeration Podcast, hosts Brett Wetzel and Kevin Compass welcome new sponsor NDL Industries with guests Lucas (a Lithuania-based product manager with CO₂ rack design experience) and Amit (VP of Sales in Austin). They discuss the rapid growth of CO₂ refrigeration driven by regulations and efficiency improvements like parallel compression and ejectors, and the need for readily available parts—highlighting NDL’s US distribution hub near Memphis and 130 bar UL-rated fittings. The conversation digs into CO₂ valve and check-valve ratings (UL vs CRN testing), actuator torque challenges, and NDL’s upcoming motorized three-way valve with clearer positioning and positive stops. They also cover service valve/Service-T design to reduce brazed joints, plus real-world transcritical heat reclaim behavior and gas cooler sizing and climate impacts.

•Brett Wetzel and Kevin Compass open theadvanced Refrigeration podcast with complaints about constant travel and terrible hotels, including broken blinds, bad smells, and cockroaches, plus a rule for avoiding sketchy areas. Kevin recounts a brutal week on a jobsite with an electrical contractor who miswired coils, phases, and controls, causing repeated troubleshooting, power trips, and a major shutdown when rooftop unit drainage spilled into an electrical trough. He then describes training in Chino, California on a Hussmann CO₂ rack with redundant valves, a suspected stuck oil solenoid causing overheated oil lines and high bypass activity, and how correcting it reduced compressor speed. They debate ejectors and parallel compression control, flash tank instability, oil pressure issues, controller limitations, and note miswired electric defrost heaters and CO₂-to-CO₂ heat exchanger failures.

Brett Wetzel and Kevin Compass open the advanced Refrigeration podcast with complaints about constant travel and terrible hotels, including broken blinds, bad smells, and cockroaches, plus a rule for avoiding sketchy areas. Kevin recounts a brutal week on a jobsite with an electrical contractor who miswired coils, phases, and controls, causing repeated troubleshooting, power trips, and a major shutdown when rooftop unit drainage spilled into an electrical trough. He then describes training in Chino, California on a Hussmann CO₂ rack with redundant valves, a suspected stuck oil solenoid causing overheated oil lines and high bypass activity,and how correcting it reduced compressor speed.

They debate ejectors and parallel compression control, flash tank instability, oil pressure issues, controller limitations, and note miswired electric defrost heaters and CO₂-to-CO₂ heat exchanger failures.

Brett Wetzel and first-time guest Kevin Compass kick off the Advanced Refrigeration Podcast in a chaotic mood after tech failures, traffic, and a rough week on a large grocery-store refrigeration job where electricians are slowing progress, skipping work on energized circuits, and delaying rack startup. They talk about traveling, hotel safety concerns, sleep deprivation, and returning the following week because verification is only partially complete and the rack couldn’t be started. The conversation shifts into Danfoss case control and pack controller details, including correcting earlier misunderstandings about fan shutdown logic being handled automatically by the pack controller if programmed correctly. Brett walks through Danfoss thermostat control settings (on/off vs modulating), notes recommended minimum modulation percentages (around 3.6–4), and discusses guidance from Brian Rogers about avoiding modulating on dual-temp islands unless using an EPR, especially on CO2 systems due to potential icing issues. They explain S3/S4 sensor weighting (inlet vs discharge air), caution against using weighted control where return air can be blocked (turkey, produce, beer cases), and discuss how modulating control can reduce cycling and improve rack stability—especially on low-temp circuits that affect medium-temp load and BGV stability. They debate CO2 ejector versus high-pressure valve operation, with Brett noting updated information that ejectors run as primary until high utilization before the HPV opens. The episode also covers Danfoss network scheduling for case enable/shutdown staging, group-based defrost schedules, why long stage delays can cause short cycling after power blips, the value of adding minimum loop protections, and the confusion of chained controller calculations. They end by noting a potential wiring/relay issue on ejector solenoids (not all on solid-state relays), joking about communication challenges with a Scottish colleague, and signing off as Brett heads to sleep before an early flight.

Danfoss Case Controllers Enables and Control, Does GoogleTranslate Do Scottish?? Episode-508Brett Wetzel and first-time guest Kevin Compass kick off the Advanced Refrigeration Podcast in a chaotic mood after tech failures, traffic, and a rough week on a large grocery-store refrigeration job where electricians are slowing progress, skipping work on energized circuits, and delaying rack startup. They talk about traveling, hotel safety concerns, sleep deprivation, and returning the following week because verification is only partially complete and the rack couldn’t be started. The conversation shifts into Danfoss case control and pack controller details, including correcting earlier misunderstandings about fan shutdown logic being handled automatically by the pack controller if programmed correctly. Brett walks through Danfoss thermostat control settings (on/off vs modulating), notes recommended minimum modulation percentages (around 3.6–4), and discusses guidance from Brian Rogers about avoiding modulating on dual-temp islands unless using an EPR, especially on CO2 systems due to potential icing issues. They explain S3/S4 sensor weighting (inlet vs discharge air), caution against using weighted control where return air can be blocked (turkey, produce, beer cases), and discuss how modulating control can reduce cycling and improve rack stability—especially on low-temp circuits that affect medium-temp load and BGV stability. They debate CO2 ejector versus high-pressure valve operation, with Brett noting updated information that ejectors run as primary until high utilization before the HPV opens. The episode also covers Danfoss network scheduling for case enable/shutdown staging, group-based defrost schedules, why long stage delays can cause short cycling after power blips, the value of adding minimum loop protections, and the confusion of chained controller calculations. They end by noting a potential wiring/relay issue on ejector solenoids (not all on solid-state relays), joking about communication challenges with a Scottish colleague, and signing off as Brett heads to sleep before an early flight.

Brett Wetzel and recurring guest Kevin Compass kick off with a chaotic hotel minibar mishap where simply picking up items triggers expensive charges, then roll into a wide-ranging, comedic shop talk episode. Kevin describes a slow work week of wire-pulling and quoting jobs and mentions traveling to Texas soon, while Brett recaps two weeks of nonstop travel from Vegas to Newark, Pennsylvania (visiting Remco), and New York for an NASRC event—contrasting “cake” startups with jobs where everything is on fire. They swap stories about racks being mysteriously shut off (including by people in mechanical rooms) and a condo complex protesting rooftop condenser noise until an Aldi blocked a shortcut with a parked semi. The bulk of the episode dives into Danfoss CO₂ rack controls and tuning: comparing Danfoss algorithms to E3, discussing PI settings (KP and TN), neutral band behavior, zone acceleration/deceleration, and how to export/copy controller settings to PDF for before/after records—then using ChatGPT to identify changes. They debate relief setpoints and high-pressure cutouts (including 130 bar/1885 psi references), question why certain pressure limits match, and complain about Danfoss gas cooler fan control relying on temperature instead of pressure, especially in cold weather. Brett explores IO configuration and general-purpose controllers while trying (and failing) to map sensor “S7,” then proposes relay-based fan bank staging as a workaround for EC motors that don’t turndown low enough. They also cover double digital compressor control, advising to set “frequency” scaling to 0–100 (capacity) rather than 0–60, and clarify analog output differences between IDCM modules and Copeland CoreSense (including 1–5V). The conversation shifts to parallel compression and ejector systems: setting up multi-ejector models/blocks, how logic may switch from high-pressure valves to ejectors, and concerns that ejectors/parallel compression can rob already-light medium-temp load. Reviewing piping/prints, they critique oil reservoir piping, note an oil vent differential of 2.4 bar as too low, discuss desuperheater risks in cold ambient conditions, and complain about pre-relief valves and gas cooler bypass as problematic “band-aids.” They wrap with Brett’s early Monday flight to Texas, jokes about being recognized on job sites, and their usual back-and-forth sarcasm and banter throughout.

Danfoss Programming, Watching Brett Fail, AHR Recap, Mini Bar Mayhem-Episode-507

Brett Wetzel and recurring guest Kevin Compass kick off with a chaotic hotel minibar mishap where simply picking up items triggers expensive charges, then roll into a wide-ranging, comedic shop talk episode. Kevin describes a slow work week of wire-pulling and quoting jobs and mentions traveling to Texas soon, while Brett recaps two weeks of nonstop travel from Vegas to Newark, Pennsylvania (visiting Remco), and New York for an NASRC event—contrasting “cake” startups with jobs where everything is on fire. They swap stories about racks being mysteriously shut off (including by people in mechanical rooms) and a condo complex protesting rooftop condenser noise until an Aldi blocked a shortcut with a parked semi. The bulk of the episode dives into Danfoss CO₂ rack controls and tuning: comparing Danfoss algorithms to E3, discussing PI settings (KP and TN), neutral band behavior, zone acceleration/deceleration, and how to export/copy controller settings to PDF for before/after records—then using ChatGPT to identify changes. They debate relief setpoints and high-pressure cutouts (including 130 bar/1885 psi references), question why certain pressure limits match, and complain about Danfoss gas cooler fan control relying on temperature instead of pressure, especially in cold weather. Brett explores IO configuration and general-purpose controllers while trying (and failing) to map sensor “S7,” then proposes relay-based fan bank staging as a workaround for EC motors that don’t turndown low enough. They also cover double digital compressor control, advising to set “frequency” scaling to 0–100 (capacity) rather than 0–60, and clarify analog output differences between IDCM modules and Copeland CoreSense (including 1–5V). The conversation shifts to parallel compression and ejector systems: setting up multi-ejector models/blocks, how logic may switch from high-pressure valves to ejectors, and concerns that ejectors/parallel compression can rob already-light medium-temp load. Reviewing piping/prints, they critique oil reservoir piping, note an oil vent differential of 2.4 bar as too low, discuss desuperheater risks in cold ambient conditions, and complain about pre-relief valves and gas cooler bypass as problematic “band-aids.” They wrap with Brett’s early Monday flight to Texas, jokes about being recognized on job sites, and their usual back-and-forth sarcasm and banter throughout.