Engineering Bulletin

Need for a Flow Control Device
A grease interceptor, correctly designed to separate light density substances from
wastewater, will not by itself govern or regulate the flow of water through the inter-
ceptor at all times to sufficiently assure the “flotation” separation of the substances
which are to be intercepted at maximum efficiency.
The flow control fitting is designed with an integral orifice to give a predetermined
optimum flow rate, thus eliminating turbulence in the interceptor, which could
otherwise occur from sudden surges in the drainage line.
The orifice openings are related to the size and flow rating of the grease interceptor.
Standard orifice sizing is for gravity flow conditions where no pressure buildup is
considered. If an interceptor is operating at maximum flow levels, a head may
develop, in which case overload conditions may still exist.
Trap Flow Rate Standard Size
Size/GPM Orifice/Inches
45/8
75/8
10 15/16
15 15/16
20 1-1/4
25 1-1/4
35 1-1/2
50 1-3/4
75 2-1/4
100 2-1/4
125 2-5/8
150 2-5/8
200 3-1/4
250 3-1/4
300 4
400 4-1/2
450 4-7/8
500 4-7/8
GENERAL PRODUCT INFORMATION, continued
Z1108/Z1108-L Flow Control Fitting
Every interceptor should have a flow control fitting and flow
control fittings should be properly vented. The flow control
fitting is installed in line between fixture and interceptor. Its
function is to regulate the flow so that it will not exceed the
flow rate capacity of the interceptor, thus ensuring fool-proof
operation and maximum efficiency.
*Orifice size varies according to size of interceptor.
Z1108 Dimensional Data
A (IP) B C D
1-1/2 5-7/16 2-7/8 3-13/16
2 5-7/16 2-7/8 3-13/16
3 6-1/8 4 4-1/8
4 6-13/16 5 4-3/4
Z1108-L Dimensional Data
AB C D
1-1/2 5-3/4 3-3/8 1-7/16
2 5-3/4 3-3/8 1-7/16
3 6-3/8 3-3/4 2-3/4
4 9-1/8 5-1/4 5-1/4
Settings for Zurn Flow Control Fitting
Consider a Z1170, #300 Interceptor, rated at 10 GPM, installed
with the Z1108 or Z1108-L flow control fitting. When installed
with a scullery sink in compliance with PDI standards for grease
interceptors, this Interceptor can be recessed in the floor
(shown solid) or placed on the floor (shown dotted).
Maximum distance in inches from bottom of sink to centerline of flow
control fitting inlet (D).
‘H’ INTERCEPTOR SIZE
SINK
DEPTH 100 200 300 400 500 600 700 800
‘D’ Dimensions in Inches
6 7.5
6.5 7.5 10 10 10
7 6.75 7.5 10 10 10
7.5 6.75 7.5 9.25 9.25 9.25
8 6.0 6.75 9.25 9.25 9.25
8.5 6.75 8.5 8.5 8.5
9 6.0 8.5 8.5 8.5
9.5 7.75 7.75 7.75
10 7.75 7.75 7.75
10.5 7.0 7.0 7.0 10.0 10.0 11.0
11 7.0 7.0 7.0 10.0 10.0 11.0
11.5 6.5 6.5 6.5 9.25 9.25 10.5
12 9.25 9.25 10.5
12.5 8.5 8.5 9.5
13 8.5 8.5 9.5
13.5 7.75 7.75 9.0
14 7.75 7.75 9.0
14.5 7.0 7.0 8.0
15 7.0 7.0 8.0
15.5 5.0 5.0 7.5
16 7.5
18 5.75
Important
Check size of Interceptor to determine setting as indicated below.
NOTE: All figures represent maximum distances in inches.
Figures between horizontal lines are recommended.
Z1108 Installation
Z1108-L Installation
Page 3