HARNESS AS-PUMP 3500743 - Caterpillar

Check both differential pressure gauge (5) follower needles for readings above 172 kPa (25.0 psi) to help identify which filters are restricted.
Illustration 34 g02733544
(18) Differential Pressure Slug Valve
Once all restrictions are corrected, reset slug valve (18) by moving lever from TRIPPED position to SET position.Note: If slug valve will not reset, or closes again, refer to the Troubleshooting Section in this manual, or contact your local Cat dealer for assistance.
The Slug valve is factory set to 172 kPa (25.0 psi) differential pressure. Do NOT adjust the factory setting. Changing the setting can result in improper fuel filtration and damage to bulk fuel filtration system components.
Note: To ensure fuel quality, have fuel cleanliness tested on a regular basis. For more information on fuel quality testing, refer to the latest version of Service Manual, SEBU6250, Caterpillar Machine Fluid Recommendations.Service Parts
Illustration 35 g02733610
(24) Typical Pre-filter Element (25) Typical Coalescer Element (26) Typical Separator Canister
Table 3
Service Parts    
Item     Part No     Description     Qty    
(24)     372-1039     Pre-filter Element Kit 1     1    
(25)     372-1038     Coalescer Element Kit 2     1    
(26)     372-1041     Separator Canister 3     4    
-     307-0655     Optional Heater (120 VAC)     1    
-     307-2569     Optional Heater (240 VAC)     1    
1 Includes two pre-filter elements and one pre-filter vessel o-ring seal.
2 Includes 5 Coalescer elements and one Coalescer vessel o-ring seal.
3 Separator canisters do not require replacement unless damaged or corroded.    Troubleshooting
Table 4
Troubleshooting Chart    
Problem     Possible Cause     Possible Solution    
No fuel flow.     Inlet or outlet valve is closed.     Completely open inlet/outlet valve.    
Fuel hose is kinked. Straighten hose and/or provide larger hose.    
Automatic slug valve shutdown. Check differential pressure gauge follower needles for differential pressure reading greater than
172.0 kPa (25.0 psi). The slug valve will close if filters are restricted. Change filter, elements, and reset slug valve.    
Check sight glass for high water accumulation. Wait until system purges water or drain water manually. Reset slug valve.
Differential gauge reading greater than
69.0 kPa (10.0 psi) at start-up.     Air in the system.     Open vent valve at top of pre-filter vessel to release trapped air.    
Differential gauge reading greater than
172.0 kPa (25.0 psi).     Filter elements are restricted.     Replace filter element and clean vessel.
Reset slug valve, if necessary.    Maintenance Record
Replace filters at least every six months. Clean debris from vessels annually, or as needed to maintain cleanliness.
Table 5
370-8571 Bulk Fuel Filtration Group Maintenance Record    
Date     Maintenance Description     Performed By