This paper deals with computational investigation of a simplest pulsating heat pipe (PHP) configuration and interdependence of some factors that determine the likeliness of oscillations to sustain or decay. The focus of this paper is on some extremities leading to the oscillations which always decay. The major thrust of study has been given to the effect of "operational triad" on the sustainability of oscillations, where operational triad has been taken as a combination of the hot and cold section temperatures of PHP and the fluid reservoir pressure. Various combinations of the triad elements have been explored and it is observed that certain combinations stringently promote the oscillations to decay. For different extremities within the triad, the mechanisms and factors responsible for decay of oscillations have been studied in detail. The effect of adiabatic length on oscillation sustainability has also been discussed along with the corresponding decay mechanism. © 2018 by Begell House, Inc.