A four port non-bleed pneumatic relay which produces a modulating pressure output, proportional in a fixed ratio to pilot input changes. It is used to control pneumatic valve or damper actuators in sequence from a single thermostat. Replacement devices are available for Johnson, Powers, Robertshaw, Barber-Colman, and older Honeywell devices.

  • Adjustable pilot start point pressures.
  • Two pilot pressure spans available.
  • Four sharp-barb air connections.
  • Molded plastic construction with neoprene.
  • Mounting clip provided.

  • Description: Wall, In-Line or panel mounted Pneumatic Four Port Ratio Relay
  • Type: Pneumatic, Four Port Ratio Relay
  • Action: Direct Acting
  • Operation: Produces modulating pressure output proportional to pilot pressure input changes
  • Airflow Usage: 0.002 scfm (1.0 mL/s) maximum
  • Air Connections: Barb fittings, Port 1: 1/4 in. (6 mm) O.D. plastic tubing; Other Ports: 5/32 in. (4 mm) O.D. plastic tubing
  • Capacity: 0.039 scfm at 1 psi differential (18 mL/s at 5 kPa differential)
  • Mounting: Wall or In-line or panel
  • Maximum Safe Operating Pressure (psi): 30 psi
  • Operating Humidity Range (% RH): 5 to 95% RH
  • Temperature Range: 0 F to 140 F
  • Output Span: 3 to 13 psi
  • Pilot input span: 5 psi input span for 3 to 13 psi output
  • Pilot Start Pressure: Adjustable 0 to 10 psi
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