Schier GB-500-250HF User manual

Contents
Special Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Getting to Know the GB-500-250HF . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Buried Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7
On the Floor Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-10
Installation Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
INSTALLATION GUIDE
GB-500-250HF
250 GPM Grease Interceptor for
Indoor/Outdoor Installation
913-951-3300 | schierproducts.com
© Copyright 2023 Schier Products Company, 01/01/23
LIFETIME GUARANTEED GREASE INTERCEPTORS

When Installing Interceptor Inside
If your dishwashing sink(s)
discharges into a floor
drain/sink (drain), you must
regulate the flow into the
drain to avoid an overflow
of water onto the kitchen
floor. This can be done by
installing a valve or flow
restriction cap on the sink
piping that discharges into
the drain. See drawing
for guidance. For detailed
guidance on indirect connections, go to:
webtools.schierproducts.com/Technical_Data/Indirect_Connections.pdf
Fernco or similar rubber
flow restriction end cap
SPECIAL PRECAUTIONS
For Schier Grease Interceptor Installations - Failure to follow this guidance voids your warranty
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. Models GB-50,
GB-75, and GB-250 use model AK1 anchor kit.
Model GB-500 uses model AK2 anchor kit for
use with deadmen anchors.
Fully Support Base of Unit
Install unit on solid, level surface in
contact with the entire footprint of unit
base; for 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
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.
Hydrostatic Slabs
(or 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.
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.
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).
pipe supports
InterceptorInterceptor
concrete slab subject to hydrostatic pressure
watertight
concrete
vault
InterceptorInterceptor
concrete floor
suspended installation
InterceptorInterceptor
max water table height for
direct burial
deadman anchor
nylon strap
turnbuckle
InterceptorInterceptor
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.
installation
instructions
AGS2
Above Grade Installation Support
(for Model GB-500 Only)
The wet weight of the interceptor combined with
high temperature kitchen water creates the
potential for tank deformation when installed
above grade. Model GB-500 installed above grade
must be installed with Above Grade Support Kit
model AGS2 to maintain structural integrity
DO NOT
COMPACT
BACKFILL
DO NOT AIR TEST UNIT OR RISER SYSTEM!
Schier | GB-500-250HF Installation Guide
page 2 of 11

GETTING TO KNOW THE GB-500-250HF
1. Pickable Cast Iron Cover (standard)
2. Cover Gasket
3. Safety Star (x2)
4. Safety Star Tether (x2)
5. Cover Adapter (x2)
6. Cover Adapter Gasket Assembly(x2)
with Upper and Lower Stainless Steel
Band Clamps
7. Bulkhead Connection Retaining Nut
8. Bulkhead Connection Gasket
9. Inlet Bulkhead Connection (optional) 4"
FPT (x2)
10. 4" Cleanout Plug (x4)
11. Inlet Diuser
12. Inlet Diuser Retaining Nut
13. Inlet Diuser Foot Retaining Nut
14. Inlet Diuser (Foot)
15. Inlet Bulkhead Connection (standard) 4"
FPT
16. 4" Plain End Fitting (x2)
17. 3" Plain End Fitting (x2) (optional)
18. Composite Cover Bolts
and Washers (x8)
19. Bolted Composite Cover (optional)
20. Air Relief/Visual Access
21. Outlet Diuser Retaining Nut
22. Outlet Diuser
23. Outlet Bulkhead Connection (optional) 4"
FPT (x2)
24. Outlet Bulkhead Connection (standard)
4" FPT
25. 7/16" Nut Driver Bit
Schier | GB-500-250HF Installation Guide
page 3 of 11
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Special Precautions
BURIED INSTALLATION
1a 1b
1c
Leak?
Call customer care at 913-951-3300
8a – 5p M – F CST
1Test tank for water tightness
Fill Line
Cap all connection points with 4" cleanout plugs using
pipe thread sealant or tape approved for use with
plastics.
Remove covers. 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.
Max Water Level
Risers are not designed
to retain water
5
3 Risers (94") Max
4
InterceptorInterceptor
Install interceptor as close as
possible to fixtures being
served
1 3
Provide at least 16"
clearance above unit for
routine maintenance.
2
16" min.
Schier | GB-500-250HF Installation Guide
page 4 of 11
ODOR ALERT!
Interceptor is not a sewer
gas trap.
All upstream fixtures must
be trapped
InterceptorInterceptor

BURIED INSTALLATION
2b 2c
Remove safety star insert, leave
tethered to unit.
Unscrew diuser retaining nut and
remove inlet diuser.
Unscrew foot retaining nut
and remove inlet diuser
foot.
Rotate diuser
top toward
chosen inlet and
replace foot, ensure it
points toward unit front
wall. Hand tighten foot
retaining nut.
Insert diuser
into chosen
inlet and
hand tighten
retaining nut.
3e
Cap all unused connection points with 4"
cleanout plugs using pipe thread sealant
or tape approved for use with plastics.
2 Set Up Inlet Diuser
2a Choose inlet location. 2d
2e 2f
Side inlet
3 Set Up Outlet Diuser and Install Cleanout Plugs
3a Choose outlet location.
Side outlet
3b 3c 3d
Remove safety star insert, leave
tethered to unit.
Unscrew diuser retaining
nut and remove outlet
diuser.
Rotate diuser toward chosen
outlet, insert and hand tighten
retaining nut.
Straight-through
Straight-through
Schier | GB-500-250HF Installation Guide
page 5 of 11

Excavate hole at least 18" larger than interceptor on all
sides and 12" 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.
5a 5b
12" or more
18" 18"
12"
5 Excavate Burial Pit
BURIED INSTALLATION
7 Wet or Air Test Piping Per Local Code
Doing so may result in property damage, personal injury or death.
DO NOT AIR TEST UNIT OR RISER SYSTEM!
1Leak? Call customer care at
913-951-3300
8a – 5p M – F CST
Lower unit into pit and set level. Mechanically couple inlet
and outlet drainage lines to unit. Do not solvent weld.
Ensure all upstream fixtures are trapped. Vent per local
code. Installation of 2-way cleanout tees to grade (by others)
is recommended.
6b
6 Connect Piping
Screw plain end fittings (included) into bulkhead
fittings using pipe thread sealant or tape approved
for use with plastics. 6" connection types come
pre-installed from the factory.
6a
4" Plain End
4" FPT
Outlet
Connection
2-Way
Cleanout Tee
Inlet Connection
Schier | GB-500-250HF Installation Guide
page 6 of 11

BURIED INSTALLATION
8 Bring Covers Flush-to-Grade
The GB-500-250HF is ready for burial depth of 49-1/2" from finished grade to bottom of tank (or 10-1/2" to centerline of inlet).
Deeper burials will require extending the Cover Adapters and possibly adding risers.
Measure dimension X to determine riser height needed.
8a
Install risers if required
(see instructions included with FCR2).
8b
Riser Height Risers
Needed Required
0" - 4" None (use adapter)
>4" - 34" FCR2 (x2)
>34" - 64" FCR2 (x4)
>64" - 94" FCR2 (x6)
If required, Cover Adapters
may now be tilted up to 10º in
any direction using gasket
flexibility.
8f
Adjust Cover Adapter heights as
needed. Maintain a minimum
2-1/2" insertion depth.
2-1
/
2" minimum
8d
Loosen the
Cover Adapter Upper
Band Clamp using 7/16" Nut
Driver Bit.
8c
Tighten Upper
Band Clamp to 5 -8 ft. lbs. of
torque using 7/16" Nut Driver
Bit.
8e
9 Backfill and Finished Grade
Fill unit with water for stabilization and
float-out prevention.
9a 9a
Vehicular Trac Areas:
Minimum 8" thick concrete slab with rebar required. Thickness of
concrete around covers to be determined by specifying engineer.
If trac loading is required the concrete slab dimensions shown
are for guideline purposes only. Concrete to be 28 day
compressive strength to 4,000 PSI. Use No. 4 rebar (ø 1/2") grade
60 steel per ASTM A615: connected with tie wire. Rebar to be
2-1/2" from edge of concrete and spaced in a 12" grid with 4"
spacing around access openings.
Pedestrian Trac or Greenspace Areas:
Minimum 4" thick concrete slab with rebar required.
Backfill evenly around tank using crushed
aggregate (approximately 3/4" size rock or
sand with no fines)or flowable fill. Do not
compact backfill around unit.
TOP VIEW 18"
min
45º
18"
min
18"
min
18"
min
Concrete Slab
Rebar
Pour concrete slab to finished grade.
9c
9c1
Rebar
Schier | GB-500-250HF Installation Guide
page 7 of 11

Special Precautions
ODOR ALERT!
Do not install air
gap on outlet side
of interceptor.
1Install interceptor as close as
possible to fixtures being served
3
Provide at least 16"
clearance above unit for
routine maintenance.
16" min.
4
ON THE FLOOR INSTALLATION
ODOR ALERT!
Interceptor is not a sewer gas trap.
All upstream fixtures must be trapped
2
1a 1b
1c
Leak?
Call customer care at 913-951-3300
8a – 5p M – F CST
1Test tank for water tightness
Fill Line
Cap all connection points with 4" cleanout plugs using
pipe thread sealant or tape approved for use with
plastics.
Remove covers. 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.
Schier | GB-500-250HF Installation Guide
page 8 of 11

ON THE FLOOR INSTALLATION
2 Set Up Inlet Diuser
2b 2c
Remove safety star insert, leave
tethered to unit.
Unscrew diuser retaining nut and
remove inlet diuser.
Unscrew foot retaining nut
and remove inlet diuser
foot.
Rotate diuser
top toward
chosen inlet and
replace foot, ensure it
points toward unit front
wall. Hand tighten foot
retaining nut.
Insert diuser
into chosen
inlet and
hand tighten
retaining nut.
3e
Cap all unused connection points with 4"
cleanout plugs using pipe thread sealant
or tape approved for use with plastics.
2 Set Up Inlet Diuser
2a Choose inlet location. 2d
2e 2f
Side inlet
3 Set Up Outlet Diuser and Install Cleanout Plugs
3a Choose outlet location.
Side outlet
3b 3c 3d
Remove safety star insert, leave
tethered to unit.
Unscrew diuser retaining
nut and remove outlet
diuser.
Rotate diuser toward chosen
outlet, insert and hand tighten
retaining nut.
Straight-through
Straight-through
Schier | GB-500-250HF Installation Guide
page 9 of 11

Floor Below Installation Detail
6 Install AGS2 Above Grade Support Kit (sold separately)
ON THE FLOOR INSTALLATION
Mechanically couple inlet and outlet drainage lines to unit.
Do not solvent weld. Ensure all upstream fixtures are
trapped. Vent per local code.
7 Wet or Air Test Piping Per Local Code
Doing so may result in property damage, personal injury or death.
DO NOT AIR TEST UNIT OR RISER SYSTEM!
1Leak? Call customer care at
913-951-3300
8a – 5p M – F CST
The wet weight of the interceptor combined with
high temperature kitchen water creates the
potential for tank deformation when installed
above grade. Model GB-500 installed above grade
must be installed with Above Grade Support Kit
model AGS2 to maintain structural integrity. Refer
to installation instructions included with AGS2.
Above Grade Support Kit - AGS2
5 Connect Piping
5b
InterceptorInterceptor
vent per
local code
flexible PVC
couplings
Screw plain end fittings (included) into bulkhead
fittings using pipe thread sealant or tape approved
for use with plastics. 6" connection types come
pre-installed from the factory.
5a
4" Plain End
4" FPT
Schier | GB-500-250HF Installation Guide
page 10 of 11

deadmen anchors (by others)
INSTALLATION OPTIONS
1 High Water Table Installations, See Anchor Kit Model AK2
Deadmen Anchoring:
If the installation location is in a high water
table area or at risk are (including but not
limited to tidal surge areas, floodplains and
areas that receive storm water) the
GB-500-250HF must be secured to concrete
deadmen anchors (by others) using Schier
model AK2 anchor kit.
Schier | GB-500-250HF Installation Guide
page 11 of 11