4-20. RETURN DUCT ADAPTER (cont)
(2) To replace gasket or insulation:
(a) Remove as much old gasket or insulation material as possible by pulling or scraping it away from the
Dry cleaning solvent (Federal Specification P-D-680) used to clean parts is potentially dangerous to
personnel and property. Do not use near open flame or excessive heat. Flash point of solvent is 100 F
to 138F (38 C to 59 C).
(c) Coat the mating surfaces of the metal and gasket or insulation (if applicable) with adhesive (item 1
Appendix E). Let both surfaces air dry until the adhesive
is tacky but will not stick
(d) Starting with an end, carefully attach the gasket to the metal. Press into firm contact all over.
(1) Aline mounting holes with casing fasteners.
(2) Secure adapter (2) to casing with 22 screws (1).