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> Zurn 1170-8NS-4 grease interceptor / trap
Zurn 1170-8NS-4 grease interceptor / trap
zurn 1170-8ns-4 grease interceptor / trap
For nearly a hundred years, grease interceptors have been used in plumbing wastewater systems to permit free flow of drainage
from sinks and similar equipment. They have played an important role in preventing grease accumulations from clogging waste
pipes and sewer lines. They also help to improve operations at wastewater treatment facilities and prevent environmental problems
Install the interceptor as close as practical to the fixture(s) being
served. The interceptor may be placed on the floor, partially
recessed in the floor; recessed with top flush with the floor;
or fully recessed below the floor, in order to accommodate
piping and structural conditions.
Anticipate sufficient clearance for removal of the interceptor
cover and baffle for cleaning. Also, take into consideration the
possibility of pipelines becoming clogged with congealed
grease that may collect before reaching the grease interceptor.
Do not install the grease interceptor in a waste line from
a garbage grinder. Garbage grinder waste must bypass the
interceptor because rapid accumulation of solid matter will
greatly reduce the grease interceptor efficiency, preventing
operation in compliance with its rated capacity. Solid material
should not be permitted to enter the grease interceptor. In an
application where solids are present, a solids interceptor
A separate grease interceptor is recommended for each
commercial dishwasher. The size of the interceptor is
determined by the discharge rate of the dishwasher as
specified by the manufacturer.
Placement of the interceptor in a high traffic area is an
important concern. If the interceptor is to be installed flush
with the floor, it is necessary to determine whether or not the
interceptor will experience heavy-duty load traffic. The standard
grease interceptor is designed for foot and light traffic only.
If a greater load rating is required, the interceptor must be
constructed accordingly to accept the higher load.
The use of a flow control device (Z1108), furnished with all
grease interceptors, is an important factor in the operation of
the interceptor. The flow control device should be installed in
placed beyond the last connection from the fixture(s) and as
close as possible to the underside of the lowest fixture. When
two or more sinks or fixtures are combined and served by one
interceptor, a single flow control fitting can be used.
The flow control device must be properly vented to permit air
to mix with the fluid entering the interceptor. Air facilitates
separation and, more importantly, is necessary to maintain
the proper pressure, thus, the proper operating level within
Air intake for the flow control device may terminate under the
sink drain board, as high as possible, to prevent overflow or
terminate in a return bend at the same height outside of the
building. When a fixture is individually trapped and backvented,
air intake may intersect the vent stack. All installation
recommendations are subject to approval of code authority.
Grease interceptors must have a vented waste, sized in
accordance with code requirements for venting traps,
to retain a water seal and to prevent siphoning.
One interceptor to serve multiple fixtures is recommended only
where fixtures are located close together. In such installations,
each fixture should be individually trapped and back-vented.
Design and installation are key factors to the operation of a
grease interceptor. However, without disciplined maintenance,
most performances are lost. For a manual interceptor to perform
as designed, a strict maintenance schedule must be adhered
to. If adequate maintenance is not performed, excessive grease
buildup will occur until water ladened with grease passes
directly through the unit. Therefore, no matter how efficient
the design or how proper the installation, grease interceptors
perform only as well as the maintenance routine allows.
All grease interceptors must be cleaned regularly. The frequency
of grease removal is dependent upon the capacity of the interceptor
and the quantity of grease in the wastewater. Grease
removal intervals may therefore vary from once a week to once
in several weeks. When the grease removal interval has been
determined for a specific installation, regular cleaning at that
interval is necessary to maintain the rated efficiency of the
interceptor. After the accumulated grease and waste material
has been removed, the interceptor should be thoroughly
checked to make certain the inlet, outlet, and air relief ports
Cleaning can easily be performed by following the steps listed
1. Loosen and remove the fastener(s) securing the cover to
3. Remove the flow diffusing baffle and/or sediment tray
4. Wipe down the baffle assembly, disposing of grease in a
5. Clean out any liquid grease by skimming it from the top
surface. Remove any remaining solid material with a spade
6. Remove the clean-out plug on the outlet portion of the body.
Using a clean water supply, hose down and wipe the inside
7. Replace the cleaned baffle assembly back into the unit.
8. Ensure that the cover gasket material is intact and in good
working condition. Replace gasket material if it is damaged.
9. Securely refasten the cover and the clean-out plug back
Typical Zurn Grease Interceptor
In a Zurn Grease Interceptor, the static water level is at the
bottom of the outlet. Any piping into the interceptor below this
elevation will remain filled with water.
Odor from accumulated grease in an interceptor may pass
back through the piping system and through the drain opening.
An additional trap should be considered between the fixture
and interceptor. Consult local codes.
All Zurn Interceptors are 100% steel construction, coated with
a white acid resisting epoxy (A.R.C.). Z1170 Series Interceptors
are certified by the Plumbing and Drainage Institute (PDI).
Zurn Grease Interceptors are listed by the International
Association of Plumbing and Mechanical Officials (IAPMO).
Variables Affecting Grease Interceptor Performance
A higher velocity of water will contribute to a more turbulent
mixture. This will slow the grease separation process,
? Install additional flow control
fittings at all sources of flow.
2. Ratio of Grease to the Water
The higher the ratio of grease particles to the water, the
lower the efficiency of the interceptor.
? Increase the size of the interceptor.
3. Specific Gravity (Weight) of the Filtrates
Grease has a lower specific gravity than water and will
rise to the surface quickly. Grease-ladened food particles
having a higher specific gravity than water will linger and
accumulate at the bottom, eventually passing out of the
? Install a solids interceptor at the
source of solid particles, prior to the grease interceptor.
4. Possible Presence of Detergents in the System
Grease-cutting detergents will break the liquid grease
into minute particles that can cause these liquids to
5. Percentage of Maximum Flow Capacity
If the maximum recommended flow is exceeded, the
efficiency of the interceptor will decrease considerably.
6. Location of Grease Interceptor
The interceptor should be located as close as possible to
the source of grease. Waste pipes leading to the grease
interceptor may become clogged if liquid cools prior to
entering the grease interceptor.
