1543A Fairchild Model 1500A Positive Bias Relay

$780.45 / Each
  • Product Type: Biasing Relay
  • Flow Capacity: 150 SCFM (255 M³/HR)
  • Max. Output Pressure: 150 PSIG
  • Max. Supply Pressure: 250 PSIG
Fairchild Model 1500A positive bias relay with a 1-60psig range and 3/8in FNPT ports

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Product Description

The Model 1500 Positive Bias Relay is designed for applications that require an output pressure that is the sum of a controlled input signal plus a fixed bias. This pneumatic relay provides high output flow at an output pressure that represents the input signal pressure plus a preset bias. The output of the relay is the sum of the spring bias, set with the Range Screw, plus a pneumatic input signal. (Po = Ps + K); where Po is output pressure, Ps is signal pressure, and K is the spring constant set by the Range Screw.


  • Control sensitivity of 1" water column.
  • Large Supply and Exhaust Valves.
  • Soft Supply and Exhaust Valve seats.
  • A balanced Supply Valve.
  • Aspirator Tube design.
  • A separate Control Chamber.
  • Unit construction.

  • Allows use in precision applications.
  • Provides high forward and exhaust flows.
  • Minimizes air consumption.
  • Minimizes the effect of any supply pressure variation.
  • Compensates downstream pressure droop under flow conditions.
  • Isolates the diaphragm from the main flow to eliminate hunting and buzzing.
  • Allows you to service the Model 1500A without removing it from the line.

Dimension Drawing