Chamberlain RESIDENTIAL GATE OPERATOR GA420D - Manual (Page 16)

“Slowly extend the piston 1/4"
(.64 cm) from collar and draw
a mark.”
THIS S
IDE TO GA
TE
Screws
Remove Motor Assembly
Remove screws (4) and remove motor assembly. Set motor aside and place in clean, dry location.
NOTE: Turn operator over to remove screws.
Installation 16
4
5 Determine Maximum Piston Travel
To ensure proper operation, it is essential to keep the
piston from extending and retracting completely.
“Manually extend piston out
as far as possible, push back
1/4" (.64 cm) and then mark.”
“Always stay within these two marks
to prevent the piston from bottoming
out which could damage the
transmission.”
1
2
3
Piston
Motor