what are they for?

[crawflyer]

Ok, I set up my float boxes today on my new Phaneauf rig and I see two 1/2" fittings in the middle of the flue pan, one near the top and one near the bottom in the middle of the pan. What are they for?

[tuckermtn]

most likely for a sap level indicator. Its a glass sight tube that is often used when you have a preheater/hood since you can't look in quickly. look in a leader catalog I think there is a picture there...