Free U.S. Shipping & Lifetime Warranty For All Endura Flap Pet Doors

Endura Flap Thermo Sash 3e Pet Door for Sash Windows - Replacement Flap Instructions

Installation Instructions

Sash Window Panel

Installation icon Printable Version
Installation icon Difficulty Easy
Installation icon Steps 09
Installation icon Time Required 0.5 Hours
Installation icon Sections 03
Installation icon Flags 00


  • 1 Replacement Flap
  • 3 Retainer Rings


  • Magnetic Phillips head #2 screwdriver
  • Flat head screwdriver

Step 1 Position the Panel

  • Lay the sash panel down on its side so that you can see the screw holes on the sides by the flap.

Step 2 Remove Screws

  • Remove the two screws nearest to the side of the flap on both the top and bottom using the Phillips head screwdriver and the electric drill.

Step 3 Remove Side Piece

  • Slide out the side piece so that you can access the rod at the top of the flap.

Step 4 Remove Retainer Ring

  • If you have retainer rings, you will need to loosen the middle set of screws and remove the entire flap and frame assembly from the unit. Then you can pop one ring off using the flat head screwdriver.
  • If there is not a ring, instead of loosening screws and removing the flap frame assembly you can keep the assembly in place and slide just the rod out towards you to remove the flap.

Step 5 Remove Old Flap

  • Remove the old flap.
  • Position the new flap in place in the frame and make sure the magnets are attracting correctly. If they are not, try flipping the flap around (switching the interior and exterior faces).

Step 6 Stretch the Bellows

  • Sometimes the bellows (accordion-like sides of the flap) contract during shipping and prevent the magnets from attracting.
  • To fix this, remove the pivot washers from the top corners of the flap and use a blow dryer to lightly heat the bellows and stretch them back out.

Step 7 Position the New Flap

  • Slide the rod back through the top of the flap.

Step 8 Re-Install Flap Assembly

  • If you removed the entire flap and frame assembly and one of the retainer rings, install a new retainer ring with the teeth pointing out away from the flap and slide the entire assembly back into place.
  • Be sure that the tracks for the locking cover are on the same side as the width adjustment locks at the other end.

Step 9 Re-Install Side Piece

  • Screw the side piece that holds the flap assembly back in place with the two screws that you removed. If you loosened screws in the middle to remove the flap frame, tighten them back down.