How do you blow through the gauge glass in a boiler ?

[mworld]

Here is the small explanation in the document, blow through the gauge glass of a boiler.

https://docs.google.com/open?id=19rg6K7fLTkH3RwpMFlMEwHnqAtCzyNXf7ef9Maf4q9MgCy0yeMolTJUxC-3k

https://docs.google.com/open?id=1mYbszICGsFSnkLpq1Tqr26lBu85kVJDLWYLnyd1sDr-xk3VrZieddEsJVKTw