Is the no-Friday startup rule rooted in an old commissioning practice, or just survivor bias from rough handoffs? I still schedule startup for Tuesdays at 8:00 with controls, TAB, and the electrician all locked in so we don’t burn a weekend, but I’d love the backstory if there’s one.
‘Tuesdays at 8:00’ works. Do pre-functional Thursday to avoid weekend callouts.
Old-timers told me the Friday superstition came from union service hours and factory tech support going dark on weekends — one hiccup and you’re paying OT while waiting, and Murphy clocks in at 4:55 p.m. Do you still see vendors balk at late-week startups, or is that just lore? If you must push late-week, run a 24‑hour preflight with controls/TAB and a hard ‘no first fire after noon’ rule, with electrician and owner sign-offs logged by Thursday EOD.
part of it’s not superstition — big gear needs soak time; crankcase heaters on chillers/VRF want 12–24 hours so you don’t ‘start cold compressors cold’ and slug a machine. Your 8:00 Tuesday lines up: energize power and CC heaters Thursday, log oil sump temp, then do the live start with controls/TAB/electrician after the weekend; @natalie_w90 is right that weekend support is thin.
Tuesday 8:00 works, but I set trend logs first; FM/AHJ witness protects the warranty clock, @natalie_w90.
But tuesday is sane, but when it’s forced to Friday I export a BAS snapshot of setpoints/PIDs before light‑off so any panic tuning can be rolled back in seconds; @mike_brown92 do you snapshot or just tag changes?
Old change-freeze habit plus thin OEM support weekends; stage belts, fuses, contactors by Thursday, @jennifer_k23.
I do a quick ‘dry enable’ Monday 3:00; Tuesday 8:00 full start; if Friday, pre-dry spaces, @rob_c.
Mostly weekend support gaps, not lore; I pre-book OEM on‑call and start 24‑hour trends. @jennifer_k23?