Compressor Charging

The compressors need charging every through years to maintain the required He gas pressure.

Typically there is a charging inlet valve on the compressor (on the front of the SHI CNA 11C)

A cylinder of high purity He gas (99.995 I believe) is in the 222b service area and a gas manifold is fixed in place.

The cylinder, manifold and compressor should be connected, with a vacuum pump also leading to the manifold

The gas lines should be pumped out.

The manifold should be filled with He to the required pressure.

The manifold valve to gas cylinder should be shut off.

The compressor should then be charged by opening the valve connecting it to the manifold.

Repeat until the required pressure is reached.

The manifold can be left with the valves shut and charged with He.