DOCUMENT 2529
REV. E
Instruction Manual
Model 4 – Style III
Taxiway Omni-directional Light L-852T
5
Outer Lens with Heater:
Outer Lens/Heater Replacement Kit P/N 21333 contains all necessary parts to change a lens/heater
assembly. Do as stated above; however, this fixture will not have a lens retaining gasket since it is
incorporated into the heater assembly and make sure that when mounting the lens retaining bracket, the
heater wires are aligned with the slot on the lens retaining bracket so the wires are not pinched. The heater
must be unplugged from the thermostat prior to removing the lens/heater assembly.
8.6
Feed-thru Replacement
Remove and secure power to the fixture.
Turn the fixture upside down and remove the four screws
holding the inner cover to the light housing. Disconnect the power supply leads from the feed-thru terminals.
Remove the feed-thru by unscrewing the retaining collar. Clean the mounting surfaces with Isopropyl Alcohol
and let dry. Apply a thin coat of Dow Corning FS 1292 grease to the mounting flange of a new feed-thru.
Apply a drop of Loctite 242 to the feed-thru adapter threads. Screw the feed-thru retaining collar onto the
adapter; refer to Figure 4 for proper inner cover/feed-thru orientation. Torque the retaining collar to 25 - 30 in-
lbs. Inspect/replace the optical housing’s o-ring per paragraph 8.4. Assemble the inner cover onto the light
housing. The screw-hole patterns in the inner cover and light housing are offset to insure proper alignment.
Torque the mounting screws to 25 - 30 in-lbs. Perform a pressure test per paragraph 8.7. Clean the
mounting flange area of the support ring. Place the Optical Assembly into the base. Apply Loctite 242 (P/N
10048-30), per manufacturer’s instructions, to all mounting bolts and immediately torque them to 225 -235
in-lbs.
8.7
Pressure Test
A light fixture should be subjected to a 20-psi air pressure test to verify that it is waterproof whenever it has
been opened or components have been replaced. A tire valve style pressure fitting is located on the bottom
of the inner cover. Pressurize the fixture to 20-psi then place it in a tub of water or use a soap solution to
locate escaping air bubbles. Carefully inspect the areas around the lens, inner cover seal, and feed-thru
adapter for leaks. Relieve the internal air pressure before installing the fixture or attempting to repair a leak.
WARNING:
WARNING
Do not exceed 20-psi when pressure testing the fixture. Serious injury and/or
permanent damage to the fixture may result if a higher air pressure is used. Once
the pressure test is complete, be sure to relieve the air pressure.
8.8
Cleanliness and Workmanship
Service life depends upon the entire assembly being waterproof. All surfaces must be clean, dry and free of
all foreign matter if the light fixture is to operate for extended periods without requiring maintenance.
8.9
Maintenance Program
In order to insure maximum light fixture life, the installed units should be subject to a maintenance program in
accordance with the following:
