2024-384-E-AMS-National Power-Piedmont Food Processing Center - Provide and Install Generator

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CONTINUED | 8 5.4. Minimize the number of 90-degree elbows. If more than three elbows are needed downstream of the regulator to accommodate the design, swept radius elbows are recommended to minimize pressure drop. 5.5. Use of an internally registered regulator is strongly recommended. Regulators with external pressure registration lines add an additional variable into the system that can be difficult to troubleshoot should the gas pressure become unstable under high-flow conditions. 5.6. For more stable gas flow with longer gas piping, the high pressure side may be raised as high as code allows and regulate it down to generator operating pressure at the generator. (This is the same design concept used in the electrical industry; “high voltage for long distances, transformation at the loads”). This may also help reduce cost as pipe diameters can be smaller, saving material and installation costs. 6.INSTALLATION AND COMMISSIONING RECOMMENDATIONS: 6.1. Refer to Generac’s Installation Guidelines for Stationary Industrial Generators (Document #046622) for additional installation details. 6.2. Pig all gas pipes after installation to remove pipe dope, weld slag and other contaminants that could damage the regulator valve seat and cause pressure creep. 6.3. Install a dirt trap and/or screen before the gas regulator. 6.4. Set the regulator pressure with the generator running at no-load. Measurements are taken at the generator fuel pressure test port on the inside of the frame rail. For units configured for 7"-11" w.c. operating pressure, set the regulator to 11" w.c. no-load running. For units configured for 11-14" w.c. operating pressure, set the regulator to 14" w.c. no-load running. Pressure droop at full-load running will be a combination of regulator droop and pipe friction loss. Proper design will limit the no-load to full-load running pressure drop to no more than 2" w.c. and at no time can the gas pressure fall below the minimum pressure listed on the generator nameplate. Expect the lockup static pressure typically to be higher than the no-load running dynamic pressure. 7.METHODS FOR CORRECTING UNDESIRABLE PERFORMANCE: 7.1. Pressure surging and cycling: Should the regulator experience “hunting” or other unstable operating behavior, an extended vent line may be creating resonant condition on the atmospheric side of the regulator diaphragm. If this is suspected, temporarily disconnect the vent line or remove the cap from the regulator spring case and observe if the unstable behavior stops. Shortening the length or increasing the diameter of the vent line will often correct an instability caused by vent line resonance. The pipe volume between the service regulator and the generator may be insufficient to decouple the control action of the regulator and the generator’s throttle control system. Increase the pipe volume between the regulator and the generator. Change the response time of the regulator. In some cases, a small adjustment of the regulator spring (up or down 1 w.c.) will be enough to restore stability to the system. If available for the selected regulator, using the next higher spring is another inexpensive and easy to implement option. This will slow the regulator response and can reduce or eliminate the instability. Keep in mind that changing to a higher spring rate will also increase pressure droop and reduce the regulator’s maximum flow capacity which limits the applicability of this corrective measure. Natural Gas Supply System Design Guide for Generac Industrial Spark Ignited Generators Docusign Envelope ID: 2F58BEE5-DDBE-42EB-8DFA-5E2508488B04