Short answer. Andersen distinguishes an older 200 Series Perma-Shield gliding patio door with three panels in one frame from a two-panel door in one frame with an additional stationary panel in its own frame. Both can look like “three panels” when viewed across the opening; the frame architecture is different, and part ordering can depend on that difference. The manufacturer's comparison is scoped to the products offered between 1968 and 1998. [S:ANDPATIO3]
Count frames, not just sheets of glass
| Inspection question | Full three-panel Perma-Shield | Two-panel door plus attached stationary |
|---|---|---|
| How many door panels are visible? | Three | Three |
| Where are the three panels housed? | All share one frame | Two share one frame, extra stationary panel has its own frame |
| Where is the operating panel? | Between two stationary panels | Depends on attached two-panel configuration; do not infer from count |
| Does an interlock with a special lock slot appear? | Andersen uses this as one possible three-panel indicator | Absence is not by itself a definitive 2-panel diagnosis |
Andersen's illustrated comparison asks the reader to inspect the operating-panel lock side for a slot in the interlock weatherstrip that receives the special three-panel lock. It also describes an exposed interior lock hook and a latch lever marked push on the three-panel system. These are additional observed clues, not proof that a profile removed from an unknown unit is the correct replacement. [S:ANDPATIO3]
Use the operating panel safely as an identifier
With the door in normal supported operation, photograph the entire opening from inside and outside. Show the frame joins where the extra stationary panel would connect. Mark which panel actually moves, and where the latch engages. Take close-ups of the lock trim, interlock slot and any visible identification stamp or order paperwork. Do not dismantle a lock, remove tempered glass or detach an interlock to create these photos.
The exterior-view handing rule is separate. For the 200 Series Perma-Shield family, Andersen names door hand by the operating panel position viewed from outdoors and says frame/jamb weatherstrip is handed with the unit. [S:ANDPATIOHAND] A correctly identified “left-hand” door is not enough to determine whether a weatherstrip is a three-panel interlock or side-jamb strip.
Three mistakes to avoid
- “Three glass panels means the old three-panel system.” False as an identification rule: two adjacent frames can also give three visible panels.
- “I see a cutout so any interlock with a hole will work.” The manufacturer describes a distinctive lock slot, not a generic profile fit authorization.
- “The year alone proves the correct part.” A house built in 1985 may have later-replaced doors; use installed-unit identity, not house construction date.
What to ask the maker
Submit both wide frame photos, operable panel position, lock and interlock detail, and any unit mark. Ask: Is this the 1968–1998 three-panel Perma-Shield frame or a two-panel assembly with attached fixed panel? Which original interlock and jamb parts apply? Is any listed replacement still supplied for this exact construction? Ask for the correct installation/servicing document rather than adapting an unslotted part.
Manufacturer references
Andersen Help Center 000003435, Compare Two- and Three-Panel Perma-Shield Gliding Patio Doors, configuration and interlock/lock characteristics: source. Andersen 000006280, 200 Series Perma-Shield Gliding Patio Door and Replacement Part Handing, replacement part handing: source. Checked 2026-10-12. NW0053 in the separate 69 lane treats general door handing; this page's unique answer is frame architecture and lock-slot evidence.