Fig 1

Start by: Preparing hole to the proper depth with 2 to 3 inches of a modified gravel or sand on bottom so the liner is fully supported. Note: The unit is designed so you do not have to be concerned with getting the top of the frame exactly to grade. The top of the liner needs to be from 3/4 to 2 inches below finish floor. The top frame will adjust the difference later. Click Here for a printable picture.

OPEN FLAMES Avoid direct open flames or heat on the fiberglass liner. Place a damp cloth on the liner if welding or soldering in close proximity

Fig 2

Mark and cut access hole(s) for the feeder duct or conduit into the side(s) of the liner. Keep the fit as tight as possible between the liner and the feeder duct. Use a Saber saw, Hole saw or SawsAll saw with a medium tooth blade no greater than 12 teeth (coarser blades will tear the liner).

Position the liner into the hole remembering that you have 3/4" to 2" of clearance available between top of liner and finish floor. Feed the duct into the liner. Allow the duct to protrude through at least 2 inches. If an adjustor stud & nut interferes with placing the duct into the liner, cut a 2" wide slot along the top of the duct to allow it to feed through. Secure the liner in place with two steel rods driven into the ground at opposite corners.

Fig 3

Fig 4

Backfill around the liner using a hand shovel with modified gravel or sand, leaving the concrete anchors exposed. The concrete reinforcing anchor must be solidly cast into the concrete. Level the aluminum frame with the adjustor nuts to bring the top of the frame level & even with the top of the floor line when poured.

Before pouring the concrete floor, coat the sides of the aluminum frame with a form release agent, cooking spray or light grease. The frame will be raised later to align with the flooring material.

Fig 5

Fig 6

Pour concrete and trowel finish flush along the top edge of the frame. Use the top edge of the frame as a guide for the finishing tool to achieve a perfect edge. Do not allow over-flash of concrete on the top edge of the frame.

After the floor is cured, turn the 11/16" adjustor nuts (one turn on each nut at a time) to evenly raise the frame out of concrete until you achieve the proper needed offset to match your chosen flooring material. Lock the jam nut on the underside. To avoid possible flexing of the cover & frame under load, be sure that each adjustor is secure and sharing its part of the load.

Fig 7