2-1-101b

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University of the People *

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2021

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Mechanical Engineering

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Nov 24, 2024

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SERVICE BULLETIN NOTICE: The Type of Change and Recommended Compliance specified reflects Solar’s best judgment regarding the Service Bulletin. All questions should be directed to your Solar Field Service Representative. Solar, Saturn, Centaur, Taurus, Mercury, Mars, Titan, SoLoNOx, and Turbotronic are trademarks of Solar Turbines Incorporated. Cat and Caterpillar are trademarks of Caterpillar Inc. Specifications subject to change without notice. NUMBER: 2.1/101B ISSUED: July 1981 REVISED: PRODUCT: Centaur MODEL(S): GENERATOR Specifics: SUBJECT: PRESSURE REDUCING ORIFICE IN PNEUMATIC START SYSTEM PRODUCT SAFETY —REVISION NOTICE— This revision replaces the last issue of this Service Bulletin. The previous issue must be removed and discarded. Type of Change: Product Safety Recommended Compliance: Immediate Purpose: 1. To inform users of the affected generator sets of the possibility of a leak in the pressure- reducing orifice ahead of the pilot valve L355 in the pneumatic start system. 2. To inform users of generator sets with pneumatic start systems of the availability and purpose for the addition of a pressure-reducing orifice in the pneumatic start system. SERVICE BULLETIN Page 1 of 6 NUMBER: 2.1/101B

GENERAL INFORMATION: A pilot-air/gas actuated shutoff valve controls on-off flow from the supply line to the two pneumatic starter motors. The three-way solenoid-operated pilot valve (L355) opens or closes the starter motor shutoff valve. When energized, pilot pressure is vented from the shutoff valve, allowing it to open. A pressure reducing orifice has been added in the pneumatic line between the filter and the pilot valve L355 to limit pressure on the valve, ensuring that the pilot valve will open in the event of excessive incoming main air/gas supply pressure ( Figure 1 and Figure 2). Incorporation of the orifice corrects a condition which had been thought to be a faulty pilot valve plunger that did not open. During in-house testing, it was found that orifice P/N 116801-101 was leaking on two units. Ad- ditional investigation revealed several defective orifices in stock. The leaks occurred because the mating surfaces of the orifice and the attached reducer were not welded as per drawings. All orifices in stock were reworked to prevent the possibility of a leak. In addition the orifice has now been replaced with a new orifice P/N 116801-102, which is manufactured from a single-body rather than using two parts welded together ( Figure 3). Although no field reports of a leak have been received, the possibility exists that a few units may have been shipped with a defective orifice in the start system. REQUIRED ACTION: 1. Shut down engine and examine starter control pneumatic system as shown in Figure 1 and Figure 2, to determine if system has an orifice installed. 2. If an orifice is not installed, the latest model orifice P/N 116801-102 may be ordered from your local parts depot. the addition of this orifice is recommended. Without the orifice, the pilot valve for the starter motor shutoff valve could fail to operate, preventing a start. Refer to installation instructions for orifice installation. 3. If an orifice is installed, check part number. If P/N 116801-101 is installed, check area close to orifice to determine if it is leaking. A small leak will require the use of leak check liquid (soapy water) or preferably a gas sniffer, if natural gas is used for starting. If P/N 116801-102 is installed, the leak problem does not exist, and the unit can be restarted. 4. If P/N 116801-101 is installed and found to be leaking, the following procedure should be followed: a. Open all circuit breakers. b. Close the natural gas hand valve ahead of the Solar package. c. Tag controls and hand valve to prevent an inadvertent or unexpected start. Page 2 of 6 SERVICE BULLETIN NUMBER: 2.1/101B

d. Remove the orifice, and cap or plug open lines. e. The orifice should be taken to a safe area (designated OK for open flame and welding) and rewelded. Refer to Figure 3 showing the area where the possibility of a weld leak could occur. The orifice can be replaced with P/N 116801-102 which is directly interchangeable and can be ordered from your local parts depot. f. Remove caps and plugs in line, reinstall orifice, remove tags, close circuit breakers, open hand valve. g. Recheck to ensure there is no more leakage, and restart the unit. Installation instructions for installing an orifice on a package where one was not previously installed are as follows: The parts listed below should be on hand prior to installation. (Refer to Figure 2.) NUMBER DESCRIPTION QUANTITY 116801-102 Orifice 1 903295C1 Reducer (1/4 to 3/8 inch) 1 23942R1 Swivel Tee (1/4 inch) 1 1. Shut down unit, and allow time for completion of post lube. 2. Open all circuit breakers. 3. Close the natural gas hand valve ahead of the package. 4. Tag controls and hand valve to prevent inadvertent or unexpected start. 5. Remove existing tee P/N 24028R1 between filter and relief valve. 6. At the tee end of line to filter, use a tube cutter (to avoid metal chips contaminating the start system) and remove a section of line sufficient to allow installation of reducer, orifice, and swivel tee P/N 23942R1. 7. Flare end of cut line and install orifice and reducer. 8. Reconnect swivel tee and liens ( Figure 2). 9. Remove tags, close circuit breakers, open hand valve. 10. Check all connections to ensure there are no leaks and restart the unit. SERVICE BULLETIN Page 3 of 6 NUMBER: 2.1/101B

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