HARNESS AS-LIGHTING 2178672 - Caterpillar

What would trigger the slug valve to shut down?
The slug valve will shut off, stopping fuel flow through the valve in three operational instances:
High water content in the fuel or the fuel level in the storage tank is low.In most cases, the coalescer elements are capable of separating the water, but the drain system on the coalescer will not be able to drain the water from the coalescer vessel as quickly as it accumulates in the bottom. This will cause the water level in the bottom of the coalescer vessel to rise above normal levels. A float mechanism in the bottom of the coalescer vessel operates the automatic water drain. When the rising water level causes the float to reach an above normal position, the slug control valve is triggered and shuts downstream flow off completely. The purpose of this is to prevent contaminated fuel from reaching the vehicle downstream.
High filter element differential pressure.The bulk fuel filtration unit senses differential pressure across both the primary filter elements and coalescer elements. If the valve senses a high (25 psi or above) differential pressure across the pre-filter or coalescers it will shut off flow downstream to prevent the filters from collapsing and contaminated fuel from passing through the unit.
Automatic maximum flow control.The valve automatically modulates restricting flow to the maximum flow rating of the unit. Should this flow exceed the maximum rating, the valve will automatically restrict flow to limit it to the maximum flow rate.
Illustration 39 g03419551
Illustration 40 g03419552
Are the connecting flanges standard industrial size?
Yes, the isolation valves at the supply and discharge end of the coalescer units are the same size on each unit and are equipped with standard industrial size ANSI B16.5 Class 150 Forged Flanges. The 50, 100, and 200 GPM units have a 2" ID and the 300 GPM unit has a 3" ID. Refer to Table6 for Flange dimensions.
Illustration 41 g03419659
Table 6
Nom. Pipe Size     Flange Diameter (O.D.)     Flange Thickness (Q)     Hub Dia at Base (X)     Raised Face Dia. (F)     Hub Dia. at Welding Point (H)     Bore Diameter (B)    
Welding Neck and Socket Weld (B1) Slip-On and Socket Weld Min. (B2) Lap Joint Min. (B3)
1/2     3.50     0.44     1.19     1.38     .84     .62     .86     .90    
3/4     3.88     0.50     1.50     1.69     1.05     .82     1.09     1.11    
1     4.25     0.56     1.94     2.00     1.32     1.05     1.36     1.38    
1 1/4     4.62     0.62     2.31     2.50     1.66     1.38     1.70     1.72    
1 1/2     5.00     0.69     2.56     2.88     1.90     1.61     1.95     1.97    
2     6.00     0.75     3.06     3.62     2.38     2.07     2.44     2.46    
2 1/2     7.00     0.88     3.56     4.12     2.88     2.47     2.94     2.97    
3     7.50     0.94     4.25