Thanks to the responders for the info. I'll add this data to my resource files.
Believe it or not the solution to this problem was a very low fluid level in the Aqua Hot system. The move we did was a factor but as expected the rain was a coincidence.
We were in the White Mountains of New Hamshire - great outdoor area - when the Aqua Hot stopped working correctly. Since we had no sewer connection and great showers on site, used the kettle for dish water, and had other priorities, hiking, biking, and kayaking, this issued wasn't addressed promptly. When we moved I suspect that the engine heat warmed the system and resolved the click issue until it cooled down. Later the boiler fluid level was refilled. Not an immediate effect but as soon as it was turned on later the clicking stopped, and has been okay for days. Go figure.
Ed 2015 Entegra Anthem 42 DLQ
HWH Active Air, Pressure Pro, 595 Watts Solar,
2013 4D Wrangler Sahara