The 17U20 is specifically calibrated for an actuation set point of 1

This specific part is rated for a maximum of 40 psig

or specific error codes on the control board (such as T1-T5 sensor errors) when the thermistor resistance drifts out of spec

it signals closed dampers to "crack" open just enough to relieve pressure while maintaining comfort in the non-calling rooms

Browning BX65 Belt R-22 The 17U20 is specifically calibratedThe Browning BX65 Belt is a high performance Gripnotch V Belt engineered for heavy duty industrial and HVACR drive systems. Featuring a 68" Outside Diameter and a technical BX Section profile, this belt is constructed with specialized EPDM rubber to withstand extreme temperature ranges from 40F to 250F. The precision molded cogs are a critical design feature, providing increased surface area for rapid heat dissipation and allowing the belt to operate