We just commissioned a 9‑story, 180‑unit building with CO2 heat pump domestic hot water at 140°F storage into two 500‑gal stratified tanks and a VFD recirc loop, and saw about 30% lower pump kWh with zero gas on the DHW side… How are you tuning recirc return temps to protect COP (we kept it under 100°F with smart balancing and point‑of‑use mixing) while maintaining Legionella control via 140°F storage and periodic pasteurization — any field data or pitfalls?