Positive and Negative Bias Relay (M14)

Designed for applications that require an output pressure that is the sum of a controlled input signal plus or minus a fixed bias, Fairchild's Model 14 Biasing Pneumatic Relay provides versatility in its ability to provide either positive or negative biasing in a single unit. The output of the Model 14 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 combined spring constant.


  • Control sensitivity of 1/2" water column
  • Balanced Supply Valve
  • Aspirator Tube design
  • Separate Control Chamber
  • Mounting Bracket available
  • Canadian Registration Number (CRN) certification


  • Allows use in precision applications
  • Minimizes the effects of supply pressure variation
  • Minimizes downstream pressure drop under flow conditions
  • Isolates the diaphragm from the main flow to eliminate hunting and buzzing
  • Easy to install in the field
  • Certification for use in all Canadian territories and provinces

See PUB103-064 for further information.

Positive and Negative Bias Relay (M14)