Before Operation Service

TM 5-6640-214-14

(2) Vacuum pump. Remove the top plate and fill with vacuum oil supplied with the pump until it is slightly

above oil level (approximately 3 quarts) as indicated in window on the side of the pump. In operation, the oil should be

even with or slightly above the oil level as indicated in the window. If sufficient oil is not used, a good seal around the

vanes may not be maintained. If too much oil is used, oil may back through the pump trap into the vacuum' line. The oil

supplied with the pump is specially prepared for high vacuum work. For maximum pumping speeds at low pressure, no

other oil should be used. After the oil is changed, the pump must run for some time on a closed system before lowest

pressure is obtained.

b. Before Operation Service.

(1) Make sure that the vacuum pump motor is lubricated and the vacuum pump is properly filled with oil.

(2) Make certain all vacuum pump fittings are perfectly sealed.

(3) Check the condition of vacuum pump drivebelt; make sure the belt is not too tight or too loose; check belt

pulleys. See paragraph d. (3) below.

(4) Check all vacuum pipe connections for tightness.

c. During Operation Service.

(1) Check the oil level of vacuum pump after pump has been running for at least 15 minutes. The oil level

should be maintained between the oil level marks when the pump is in operation.

(2) Check the vacuum pump motor for overheating.

(3) Check the vacuum pipe connections and fittings for vacuum leaks.

(4) Check the vacuum pressure gage on the control panel.

d. After Operation Service.

(1) If the oil level of the vacuum pump is low, fill to the proper level .

(2) Correct any vacuum leaks found during operation.

(3) Periodically, the V-belt should be adjusted so that a firm downward pressure at the middle of the span will

cause a deflection of one-half to three-fourths inch (1.27 cm to 1.91 cm).

e. Air Removal and Cleaning.

(1) Turn off the pump.

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