Haha, your mysterious valve reminds me of one job I had a couple years back. Got called out to this older house—beautiful place, but the plumbing was a total maze. Anyway, the homeowner pointed out a random valve tucked behind the water heater. It didn't seem to control anything obvious, so naturally I got curious. Spent an embarrassing amount of time tracing pipes through crawlspaces and behind drywall, only to find it was leftover from an old outdoor spigot that had been removed decades ago. Someone just capped it off and left the valve there to confuse future generations like me.
As for horizontal mounting, you're probably fine if it's been working reliably this long. Usually, if there's a real issue, you'll notice some symptoms pretty quickly—noisy operation, uneven heating, or air pockets forming. Still, keeping an eye (and ear) on it never hurts. Boilers can be sneaky like that...
"Someone just capped it off and left the valve there to confuse future generations like me."
Haha, sounds about right. I've run into similar mysteries renovating older homes—it's like previous plumbers had a twisted sense of humor or something. Once spent half a day chasing down a pipe that literally went nowhere...just ended abruptly behind some drywall. No cap, no valve, nothing. Still scratching my head over that one.
Anyway, good call on the horizontal mounting. If it's been quiet and heating evenly, you're probably golden. Boilers usually let you know pretty quick if they're unhappy—knocking noises, cold spots, or weird pressure fluctuations. But yeah, never hurts to keep an ear out. Glad you finally got it sorted though; plumbing puzzles can be maddening until you crack 'em.
Ha, mystery pipes are the worst. Found one last summer that looped around in a circle behind my kitchen cabinets—no connections, no valves, just a random loop. Pretty sure plumbers get bored sometimes and leave us Easter eggs...
Haha, plumbers leaving Easter eggs... that's a good one. Reminds me of when I moved into my current place and found a pipe running straight into the attic—no cap, no valve, nothing. Took me forever to realize it was probably meant for some future expansion or venting that never happened. Sometimes these mystery pipes are just leftovers from renovations or abandoned projects. Still makes you wonder what they were thinking at the time...
