CO2 LMP Racks Hot Gas & What The Heck Is A DTR Valve ?? Episode 520 Audio

LMP Rack Deep Dive: Hot Gas Defrost, Superheat Mitigation & Refrigeration “Witchcraft”

Brett Wetzel and Kevin Compass kick off the Advanced Refrigeration Podcast with weekend plans and a chaotic start featuring mystery music and van-recorded audio, then jump into Kevin’s hectic week swapping out 40-year-old racks and venting about painfully unserviceable EPR and valve layouts while converting controls from CPC to Danfoss. Brett outlines a common VFD control issue where a 0–100% signal causes deadband, aggressive ramping, and cycling, teeing up a future demo with virtual displays. The main discussion breaks down an LMP rack P&ID with heat reclaim, low-temp hot gas defrost, suction setpoints, superheat mitigation via inversely controlled valves and plate heat exchangers, discharge pressure regulation and staged valve reopening after defrost, load shedding, oil separation strategy, and auxiliary heat exchanger quirks, then detours into cool gas defrost debate and a cutaway look at a Venturi-style “injector” device used to cool discharge gas.