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.