Instructions – Correct Installation of Capillary Tube

Definition

A capillary tube (sometimes called a “breather tube”) is a narrow tube that is inserted into the spacer between the two panes in a dual-paned window. The capillary tube equalizes the pressure inside and outside the sealed unit.

This is especially critical when shipped by air freight, as air pressure diminishes at higher altitudes. Likewise, it’s important when shipping dual-paned units to high-altitude geographical locations.

You can see the capillary tube sticking out from an outside corner of your dual-paned window unit.



Vertical Installations


Your windows are delivered with open capillary tubes, which must be sealed prior to installation.

For windows that are to be installed vertically, seal the tube (a) with a drop of silicon sealant on the opening, (b) during mild weather of 50 to 70° F, and (c) with the window unit standing vertically.

When installing the window, always ensure that the capillary tube is at the top of the window, pointing down. Never install with the tube at the bottom of the window.

If tube must be cut to facilitate installation, steps (a), (b), and (c) still apply.


Horizontal/Sloped Installations

The same instructions apply for dual-paned horizontal (e.g. skylights) or sloped installations as for vertical installations, though position of the tube at installation is not critical.

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All packages are sent insured. Our standard shipping method is FedEx Ground which delivers most domestic shipments within 7 business days but in most cases we can ship as fast as FedEx Next Day Air.