Installation Guide

Technical Bulletin
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7. Drain the Condensate.
• Follow the appliance manufacturer’s installation instructions. Some require condensate drains only for
vent systems over a certain length.
• If a drain is required, Selkirk recommends:
 Drains at all transitions from horizontal to vertical vent runs.
 Immediately before a horizontal termination.
 After every 30 feet of continuous vent.
 The first drain should be as close to the appliance flue collar as possible. Some appliances have
internal drains or drains built into their vent adapter.
 Avoid installing drains outdoors in cold climates. When transitioning from horizontal to vertical up
the outside of a building, use an elbow instead of a boot tee. Locate a drain fitting inside the
building as close to the elbow as possible. This will prevent freeze ups.
• Always connect the drain to a sanitary sewer or other approved disposal.
• Install a trap in the drain.
• Use the Drain Hose Kit – It connects easily and can also be used as a drain trap when looped. It is
available in 5- and 10-foot lengths.
8. Provide Adequate Support.
• On horizontal runs support the vent system every 6 feet and after each elbow or offset. Adjustable
sections should be supported as well.
• On vertical installations support is required at minimum after every 30 feet of vertical rise, at each floor
penetration, and at the roof penetration. For large diameter systems (12 inch and larger), most
installers find it easier to use more support brackets to support the system during installation.
• Support should be provided at the first section above a boot tee that is installed at the base of a
vertical stack.
• To support long vertical runs inside a chase or chimney, use either guy wire supports or vertical
supports. Guy wire supports work best for tight or inaccessible stacks, but require a set of guy wires
for each support. Vertical supports are mounted directly to the inside wall of the chase or chimney.
• Heat-fab guy wire supports are necessary when the vent system extends above the roofline six feet or
more.
• Use Heat-fab support brackets or strapping. Our support clamps can be used with threaded rod either
singly (as a saddle) or in pairs.
• When using clamping-style supports, do not over-tighten to the point that the vent is damaged or
deformed.
• Some installers prefer to hang perforated channel iron to form a trapeze and rest the vent on top of it.
• Consider the behavior of the appliance when planning your supports. Some appliances create pulsing
vibrations in their vent systems. Avoid attaching the supports to structural components that may
transmit vibrations to occupied spaces. Be sure the support fasteners (nuts, bolts, etc.) cannot vibrate
loose.