Kohler 20--2800 kW manual Main Fuel Tank, Fuel Lines

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			TP-5700-6
1.	Generator set skid	3.	Subbase fuel tank
2.	Side view	4.	End view

Figure 6-2 Subbase Fuel Tank

6.2 Main Fuel Tank

All main tanks should be vented so that air and other gases can escape to the atmosphere. The vent must prevent dust, dirt, and moisture from entering the tank. Return lines should be spaced as far away from the pick-up or fuel dip tube as possible. If this is not done, air bubbles could be drawn into the fuel supply line and cause erratic engine operation. Also, fuel returning from the engine will be warmed from passing through the engine. This returning fuel, if hot enough, can cause a reduction in the power of the engine. At least 5% capacity should be allowed in a diesel main tank for expansion of the fuel. If the main tank is to be located overhead, a fuel shutoff solenoid should be used to prevent hydraulic lock or tank overflowing due to excessive pressures caused by static head of fuel.

Codes requiring standby power often specify minimum on-site fuel supply. Such requirements are included in NFPA 70, National Electrical Code; and NFPA 99, Standard for Health Care Facilities. Diesel fuel will deteriorate if stored for more than a year, so the tank should not be oversized to the point that its contents cannot be used in one year of regular exercising. If there are no applicable code requirements, a tank sized for eight hours operation at rated load is suggested. Refer to the specification sheet for fuel consumption data.

Most diesel engines will operate satisfactorily on #2 domestic burner oil as furnished in most parts of the United States. The engine can be supplied from the same tank used for heating oil if both use the same fuel. This is desirable both because of the cost savings and

the added advantage that fuel will be used and replaced regularly, ensuring a fresh fuel supply for the engine. Dual usage of the fuel can be done provided the fuel oil meets the engine manufacturer’s minimum requirements for such properties as wax point, pour point, and cetane number. These factors influence cold weather starting and power output of the engine/generator. Where more than one engine or an engine and another appliance(s) are fueled from the same main tank, each engine should have its own supply line.

6.3 Fuel Lines

Fuel lines should be constructed of Schedule 40 black iron pipe or copper tubing. Galvanized pipe, fittings, or tanks should never be used with diesel fuel systems. The fuel will react chemically with the galvanized coating, causing it to peel and clog fuel filters and damage fuel injection components.

Fuel line sizes should be the minimum required to deliver the volume necessary to the equipment within an acceptable pressure drop—1 psi (0.07 kg/cm2). The use of excessively large piping increases the chance that air will be introduced into the system, and that fuel pumps will be damaged by operating dry when priming the system.

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