Schier GB-75-B User manual

Part #: 4045-042-01
Find these instructions online at: schierproducts.com/gb-75-b
Contents
Special Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Getting to Know the GB-75-B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-10
INSTALLATION GUIDE
913-951-3300 | schierproducts.com
© Copyright 2020 Schier Products Company, 09/14/2020
GB-75-B 50 GPM 99% Efficient Great Basin™Indoor/Outdoor
Grease Interceptor

Schier | GB-75-B Installation Guide
page 2 of 10
SPECIAL PRECAUTIONS
Do not install this unit in any manner
except as described in these instructions.
Doing so may result in property damage, personal injury or death.
DO NOT AIR TEST UNIT OR RISER SYSTEM!
For Schier Grease Interceptor Installations - Failure to follow this guidance
voids your warranty
Provide at least 16"
clearance above unit for
routine maintenance.
16" min.
Install interceptor as close as possible
to fixtures being served
Installation Instructions
Installation instructions and additional
components are included with the
interceptor. Read all instructions prior to
installation. This interceptor is intended
to be installed by a licensed plumber in
conformance with all local codes.
Suspended Installations
Design trapeze to support the wet
weight of the unit. Do not partially
support unit or suspend unit using
metal U-channel to create a trapeze.
concrete floor
Support Inlet and Outlet Piping
For above grade installations ensure
heavy inlet and outlet piping (such as
cast iron or long runs) is properly
supported or suspended during the
entire installation process to prevent
connection failure or damage to
bulkhead fittings.
pipe supports
ODOR ALERT!
Interceptor is not a
sewer gas trap.
All upstream fixtures
must be trapped
ODOR ALERT!
Do not install air
gap on outlet side
of interceptor.
DO NOT USE CAST IRON
COVERS IN ABOVE GRADE OR
INDOOR INSTALLATIONS
Use composite cover C24H2 for
above grade installations
Fully Support Base of Unit
Install unit on solid, level surface in
contact with the entire footprint of
unit base
High Temperature Kitchen Water
If water is entering the interceptor at excessive temperature (over 150º
F), a drain water tempering valve (DTV) and approved backflow
prevention assembly must be installed. Most state and local plumbing
codes prohibit water above 150º F being discharged into the sanitary
sewer. Water above 150º F will weaken or deform PVC Schedule 40
pipe, poly drainage fixtures like interceptors and erode the coating of
cast iron (leading to eventual failure).

page 3 of 10
Schier | GB-75-B Installation Guide
SPECIAL PRECAUTIONS
For Schier Grease Interceptor Installations - Failure to follow this guidance
voids your warranty
Below Grade Installation Slab Requirements
A concrete slab to finished grade with rebar is required when installing
interceptor below grade.
Pedestrian Traffic or
Greenspace Areas Vehicular Traffic Areas
4" min.
slab 8" min.
slab
Hydrostatic/
Pressure Slabs
When installed under a
hydrostatic slab (slab
designed to withstand
upward lift, usually caused
by hydrostatic pressure)
interceptor must be
enclosed in a watertight
concrete vault.
concrete slab subject to hydrostatic pressure
watertight
concrete
vault
High Water Table
Installations
Interceptors and risers are not
designed to withstand water table
height in excess of the top of the
unit when buried (see figure). If it is
possible for this to occur, install the
interceptor and risers in a
water-tight concrete vault or
backfill with concrete or flowable fill
(wet concrete and flowable backfill
should be poured in stages to
avoid crushing the interceptor). At
risk areas include but are not limited to tidal surge areas, floodplains
and areas that receive storm water. Great Basin™models that are direct
buried in high water table scenarios must be installed with an anchor kit.
Model GB-75 uses model AK1 anchor kit.
DO NOT
COMPACT BACKFILL
MECHANICALLY
Compact by
hand only
max water table height
for direct burial
model AK1
anchor kit
Secure Cover Adapters
Cover adapters must be secured
to base units in above grade
installations with increased head
pressure conditions. Use cover
adapter tie-down kit model ATD1.
RebarRebar
Max Water Level
Risers are not designed
to retain water
Installations with Risers
Corrugated Riser Pipe
Requirements
Riser adapter model CA2 must be
used when installing interceptors
using 24" diameter corrugated
pipe as a riser. This will adequately
embed the cover adapter in the
concrete slab, preventing
cover/cover adapture failure
under traffic rated loads.
CA2
3 FCR2 Risers Max
94"
94"
6 - 94"6 - 94"

GETTING TO KNOW THE GB-75-B
1. Pickable cast iron cover (standard)
2. Cover gasket
3. Safety Star® access restrictor
4. Safety Star® tether
5. Cover adapter
6. Cover adapter gasket assembly
with upper and lower stainless
steel band clamps
7. Inlet diffuser cover (white)
8. Inlet diffuser
9. Inlet diffuser retaining nut
10. 4" cleanout plug (x2)
11. Outlet bulkhead connection
(optional) 4" FPT (x2)
12. Bulkhead connection gasket
13. Bulkhead connection retaining nut
14. Inlet bulkhead connection 4" FPT
15. 4" plain end fitting (x2)
16. Composite cover bolts
and washers (x4)
17. Bolted composite cover (optional)
18. Air relief/visual access
19. Outlet diffuser retaining nut
20. Outlet diffuser
21. Outlet diffuser foot retaining nut
22. Outlet diffuser (foot)
23. Outlet bulkhead connection
(standard) 4" FPT
24. 7/16" nut driver bit
25. Diverter plate retaining nut (for use
when outlet diffuser is repositioned
to an optional side outlet)
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Schier | GB-75-B Installation Guide
page 4 of 10
7
Inlet diffuser
cover (white)

page 5 of 10
Schier | GB-75-B Installation Guide
1Test tank for water tightness
1a 1b
1c
Have a Leak?
Call customer care at 913-951-3300
Hours 8am-5pm CST, M-F
Cap all connection points with 4" cleanout
plugs using pipe thread sealant or tape
approved for use with plastics.
Remove cover. For base unit testing fill with water to
just above the highest connection.
Inspect unit, connections and gaskets for leaks. Check
water level at specific time intervals per local code.
Fill Line
Excavate hole at least 12" larger than interceptor on all sides and 6" deeper than tank bottom. Lay a level bed of
well-packed, crushed aggregate (approximately 3/4" size rock or sand, with no fines) in the base of hole.
12" 12"
6" 6" or more
2 Excavate Burial Pit