This could be caused by expansion of water inside the system when the water heater is left on. This expansion is supposed to be cushioned by a bubble of air in the top of the water heater. That bubble of air can be easily absorbed by the water itself, or blown out the water heater pressure relief valve. Then the pressure is so great within the lines it will find the weakest connection and leak.
Try leaving the hot water heater off and see if the leak is still there. If not you can restore the bubble in the hot water heater by turning off the water supply, hold open the water heater pressure release valve so excess water can escape, and open the nearest hot water faucet to let air in to replace it.
This is a common problem that many owners are not aware is happening. The best cure is turning the water heater off when not needing it, such as after it heats a supply of hot water.
By the way all modern Airstreams have a built in water pressure regulator inside the city water hookup connection that limits pressure to 60 psi.
Doug and Cheryl
2012 FC RB, Michelin 16, ProPride 1400
2016 Ram 1500 Laramie Crew Cab 4X4 Ecodiesel 3.92 axles
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