Kohler 20--2800 kW manual Flexible Section, Condensation Trap, Piping

5.1 Flexible Section

A section of flexible exhaust line should be installed within 2 feet (51 mm) of the engine exhaust outlet. This limits the stress on the engine exhaust manifold or turbocharger resulting from engine motion on its vibration mounts and temperature-induced changes in pipe dimensions. Never allow the engine manifold or turbocharger to support the silencer or exhaust piping weight. The flexible section should be at least 12 inches (305 mm) long.

Where threaded flexible exhaust connectors are used, a 6-8 inch (152-203 mm) length of pipe should separate them from the exhaust manifold. This will serve to reduce the temperature of the flexible connection and extend its life. It also makes it easier to remove the flexible section, if necessary, without putting excessive strain on the engine manifold.

The flexible section should not be bent or used to make up for misalignment between the engine exhaust and the exhaust piping. Since typical exhaust temperatures range from 800°F (427°C) to over 1200°F (649°C) for some engines, seamless stainless steel should be used for the flexible section.

5.2 Condensation Trap

A Y- or tee-type condensation trap with a drain plug or petcock should be installed between the engine and exhaust silencer as shown in Figure 5-3. This will prevent condensed moisture in the engine exhaust from draining into the engine when it is shut down. The trap should be drained of collected moisture periodically.

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5.3 Piping

Exhaust piping should conform to all applicable codes. In general, exhaust temperatures will be less than 1000°F (538°C) measured at the engine exhaust outlet, except for infrequent brief periods, and standards for low heat appliances will apply. For units with exhaust temperatures below 1000°F (538°C), exhaust piping should be routed a minimum of 18 inches (457 mm) from any combustible materials. If exhaust temperatures will exceed 1000°F (538°C), the minimum distance should be 36 inches (914 mm).

The heat rejected by exhaust piping, and consequently the amount of ventilating air required, can be substantially reduced by insulating exhaust piping with suitable high-temperature insulation. Exhaust temperatures are given on each generator model’s specification sheet.

Placement of exhaust silencer and piping should consider location of combustible materials. If location of exhaust cannot avoid these concerns, use a regular maintenance routine to remove combustible materials. Combustible materials include building materials as well as natural surroundings. Keep dry field grass, foliage, and combustible landscaping material whether or not seasonal a safe distance from the exhaust system.

1. Condensation trap

TP-5700-5

Figure 5-3 Condensation Trap

22 Section 5 Exhaust System TP-5700 7/93