there is a one-way ‘non-return valve’ in the Alde glycol boiler just after the gold auto air bubble bleeder on the top boiler hose. Not marked in my picture, but under the two sequential hose clamps … (View Post)
I’d like to close out this thread by saying that the boiler was indeed ruined by water left in it and freezing temperatures crushing it and cracking the weld between water and glycol. I posted a bunc… (View Post)
Both drain ports are circled. Each to one side of that metal hold down clip. No apparent one way valve between them. Might be a one way to the right of both of them. That’s upstream. (View Post)