This morning in a 1920s bungalow, the homeowner wanted me to “just tee into” a tired 1/2-inch branch feeding a range and a new tankless, under unbonded CSST with a flex connector run through a wall — then looked offended when I pulled out a permit app, manometer, bonding clamp, and test caps instead of a crescent wrench. We sized the line, bonded it, and pressure-tested instead of doing the classic sniff-and-pray; anyone else feel like 90% of gas fitting is telling jokes so the safety lecture goes down easier?
Had a ‘just tee it’ call — 1/2-inch to tankless starved. Maybe fine for a range; upsize and bond — flex-through-wall flunks?
Did one where a range and 199k tankless were on 1/2-inch over 60’, and the under-load manometer dropped hard; a quick meter clock made the case to the homeowner. If upsizing the whole run is a battle, a 2‑psi trunk with point-of-use regs and proper CSST bonding (see https://www.csstsafety.com) can save drywall — if your AHJ allows — and keeps you out of ‘tee it in’ land.
, the “just tee it in” asks always show up right before coffee… I keep a quick load-calc sheet and the Gastite bonding bulletin on my phone (https://www.gastite.com/technical-bulletins/); once they see flex-through-wall is a no-go and I’m setting the manometer, clamp, and test caps, the permit suddenly makes sense. If it’s a tiny, short run to a low-BTU cooktop I’ll consider it, but not with a range plus tankless in a 1920s bungalow — ever snap a photo of the gauge after an overnight hold to seal it?
After pulling out the manometer and bonding clamp, I print a little label for the valve: “15 psi/15 min, bonded, permit #____,” and snap a photo of the gauge with the permit — stops the “just tee into” debate on those 1920s bungalows. If your AHJ wants a 3 psi test or a wet gauge, tweak it, but the tag-and-photo combo has sold more upsizing than any speech.
And i keep an appliance-connector box in the truck and point to “not for concealed” on the label; that visual plus the permit app usually ends the debate and gets buy-in for upsizing. If they still push, I price it as a return after inspection — less drama, same result.