Hello, I too have an Excella II.... I have crystals within the windows, I'm thinking that they have 'lost' their seal, but, its not an issue that is important to me at this point.... As far as the furnace, I am lucky that I have not had an issue with it's functioning, so I have not gotten into that system.... all of the others, however, I have been.... Welcome to our AS community...
1981 Excella II 31' (rehab project)
2005 Jayco Eagle 322 FKS
2004 F-250 PS King Ranch
Retired & Having Fun