ANSI B9.1 / Compressure High pressure Cutout

[JEK1]

I am looking for an copy of ANSI B9.1, or information regarding the necessity of the high-pressure cutout switch on a 1970's vintage 90-ton reciprocating, water-cooled chiller. It seems that the cutout, set at 90% of the condenser design pressure, is there primarily to avoid opening the relief valves. Thanks in advance.

 

[TXiceman]

The standard is now know as ANSI/ASHRAE 15 and I believe the current revision level is 2004.

The Standard does require both a PSV and a high discharge pressure shut down on a positive displacement compressor. The HP switch is not to have a block valve between the switch and the sensing point on the compressor discharge. So on a recip compressor it must be on the compressor side of the compressor discharge block valve. The switch is to be set at least 10% below the PSV setting.

The standard also provides the minimum design pressures for the high side and the low side of the system based on refrigerant aqnd type condensing.

Ken

Ken
KE5DFR