Testing a 140 degree F Fenwal 27121 Rate Compensated Heat Detector using HST Series heat detector tester model HST-A-ALO-C
Fenwal Rate compensation heat detectors are available with temperature settings from 140 to 725 degrees F.
Rate compensation, Rate compensated, or Rate Anticipation heat detectors have a "virtual" set point which varies with temp rate of rise.
The HST applies heat to the detector in a way that makes it possible to determine if the detectors set point has changed significantly. A shift in the detectors set point can occur because of overheating or other physical damage to the heat detector.
Rate Compensation Verification