F-4103 Series Spring Biased Comparators

U.S. Patent No. 4,315,520

Airtrol Components F-4103 Series spring biased comparators are essentially a regulator with an adjustable bias (positive or negative), and a control or pilot input. Standard units offer a 1:1 ratio, plus or minus the initial bias. Special 3:1 and 5:1 ratio units are also available. Perfect for HVAC applications, and unique control applications requiring a positive or negative offset. Non-rising stem is available with an attractive knob, plain (allowing installation of OEM knobs) or flush for “back panel” installations.

F-4103 Series Spring Biased Comparators


REGULATOR TYPEConstant Bleed, Relieving
WETTED MATERIALSPolysulfone, Silicone, Stainless steel
MAX SUPPLY35 PSI (242 kPa)
TEMPERATURE RANGE40° – 150° F (4° – 66° C)
EFFECT OF SUPPLY VARIATION< 0.02 PSI (0.14 kPa) per 1 PSI (6.89 kPa) supply change when dead-ended
REPEATABILITY< +/- 0.05 PSI (.35 kPa)
DRIFT< .03 PSI (.21 kPa) after 24 hours

Ordering Information

F-4103 Ordering Information

Note: These comparators require an orifice restrictor in the supply line to perform as specified.

The barbed “P80” and “P85” fittings are optional.

See the following page for schematics: 4103 & 4104-Schematics