Okay, here's what I found. Fitting is a compression fitting, and appears that it wasn't quite tightened up. Put back together and pumped air in the system and no leaks. Slight bit of air coming thru the hot water drain. Thinking water heater bypass not closing all the way. Hooked up the water and filed the tank, and dewinterize the trailer. Back in business! Well hopefully. Running last of fresh water thru then will fill water heater, fire it up and see that the fitting holds. Surprised it didn't pop using it last summer. Anyway, hopefully back in business.
Thoughts...the plumbing dock is a mess, regular plumbing nightmare. Sticker says all faucets off when filling tank. True, as when filling tank water is also available to all cold faucets. Found that black tank wash hose goes up and under the bathroom sink. Makes a 180 then back down to the black tank. Must be some sort of vacuum break or back drain, or something. Also need to replace bypass valve as I don't think it's sealing 100%. My last trailer had the same water dock and I'm not a fan. Kind of like the older more simpler version. Might do up a pan and eliminate it completely.
Also water tank is above/behind axles. Heard scary stories about weak water tank mounts, and not to travel with a full tank. Well we're gonna test the theory as I'm filling the tank on the way out. Camp is only 15 miles, so wish me luck!
Pic is of the offending water line.
2011 Coachmen North Ridge 290RKD 5'er
2005 Dodge quad cab dually diesel 6'spd manual
1 weird cat with an occasional attitude problem.