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Pneumatic Three-Port Averaging Relay.


Output is the average of the two inputs. Pneumatic Three-Port Averaging Relay.

  • Product Info
  • Literature


A three-port relay averages the signals from two thermostats to control a single device such as a heating coil valve for a multizone unit. Replacements available for Johnson, Powers, Robertshaw, Barber-Colman, and olderHoneywell models


  • In-line, wall or panel mounted.
  • Sharp-barb air connections.
  • Molded plastic construction.

Product Specifications

Pneumatic Three-Port Averaging Relay
Airflow Usage
0.007 scfm (3.303 mL/s) maximum
Dimensions (in.)
1 1/2 in. high x 7/8 in. wide x 15/16 in. deep
Dimensions (mm)
38 mm high x 22 mm wide x 24 mm deep
Maximum Safe Operating Pressure (psi)
30 psi, maximum
Maximum Safe Operating Pressure (kPa)
205 kPa, maximum
Temperature Range (F)
32 F to 125 F
Temperature Range (C)
0 C to 52 C
Wall or In-line or panel
Operating Humidity Range (% RH)
5 to 95% RH
Pressure Range (psi)
Input Operating--3 to 15 psi; Output Operating --3 to 15 psi
Pressure Range (kPa)
Input Operating--21 to 103 kPa; Output Operating --21 to 103 kPa
Air connections
Barb fittings 5/32 in. (4 mm) O.D. plastic tubing
0.039 scfm at 1 psi differential (18 mL/s at 5 kPa differential)
Output pressure equals average of two input pressures