@Criswell - the yellow valve is the drain for the Alde hot water tank. If the red Alde bypass valve is set to normal (not bypass), the yellow drain valve should be closed when you fill the water syst… (View Post)
I think the Isotherm is now the frig in the 2021 model 320S. These threadS may help: https://tab-rv.vanillacommunity.com/discussion/comment/87839#Comment_87839 https://tab-rv.vanillacommunity.com/dis… (View Post)