找到厂家的说法了:
Models 8321,8322 and8323
The level of the dielectric coolant, P/N 5-030, should remain constant in the unit even after prolonged usage under normal operating conditions. As shipped, the coolant is at a factory determined level, and should be about 7/8 inch (22.2 mm) below the face of the output end, with the unit in a vertical position. The coolant should just cover the upper surface of the cubical center block of the RF section assembly. However, loss of up to 10 percent of the full tank capacity should not impair the operating efficiency of the attenuator. The coolant should be a clear light yellow color. If not, it is contaminated and should be replaced. Inspect occasionally around the clamping bands at the input and output ends for possible coolant leakage. If necessary, tighten the clamping screw and make certain the diaphragm and output housing seals are in good condition; i.e., soft, pliable and free from surface cracks.
Add Coolant
Add coolant directly into the radiator tank unit it reaches the proper level.
Replace Coolant
To replace all of the coolant, use the following procedure:
1. Pick up the attenuator and carefully pour out the coolant into a suitable container. Allow as much to drip out as possible.
2. Replace the coolant with fresh coolant, filling the radiator tank to the proper level.
CAUTION
Do not overfill the radiator tank with coolant. Room must be allowed for expansion of the heated coolant.
