Tubing systems should be checked after tapping and before the first sap flow for possible trees missed during tapping, system damage, and disconnected lines. Systems should be checked also during the season after heavy snowfall, high winds, or extended periods of non-sap flow. This can be accomplished by walking the area for a visual check. Leaks can be found best during sap flow. Artificial vacuum helps locate leaks either by noticeable air bubbles in tubing during a flow or by a hissing sound. The use of an inexpensive vacuum gauge to determine the level of vacuum at the tap is very useful. Natural vacuum can be used to locate leaks, but only during a strong sap flow when natural vacuum is developed.
Hollow taps, avoided during tapping if possible, and tubing holes caused by animal damage should also be located. Damaged tubing should be repaired immediately in anticipation of the next flow. When performing this task, an inexpensive vacuum gauge helps locate areas of low vacuum indicating the presence of leaks. Research has shown that a vacuum of about 15 inches of mercury at the taphole is optimal. This level if vacuum at the tap warrants 20 to 25 inches of mercury at the vacuum pump.
Mainlines should also be checked annually at the support trees. Make sure the tree is not growing around side pull wire and the wire is in good condition. Follow tubing system maintenance procedures throughout the sap season.