851-MS

Multiple Sensor Selector

The 851-MS Multiple Sensor Selector is an electronic signal selector designed to provide low ambient control of multiple refrigerant circuits for air-cooled condensers. Automatically selects highest liquid line temperature for use in modulating condenser fan speed and/or sequencing multiple fans when used with the 861-ASQ Sequencer.
Applications
Typically utilized with the 861-ASQ Sequencer or the 816-10D (HPVD) to monitor multiple liquid lines in order to control head pressure in low ambient temperature conditions.
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Features
  • Multiple liquid line sensing
  • Adaptable to all refrigerant types
  • Controls common airflow of multiple refrigerant circuits
  • Eliminates on/off fan cycling common with pressure limit controls
  • Output for 816-10DH(DC) control provided
  • Output for 861-ASQ Sequencer provided

Why Measure Head Pressure using Temperature instead of Pressure?

Many people assume that the best way to control the head pressure from a compressor is to directly sense the line pressure using a sensor inserted into the liquid line.
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