The most commonly used gas sampling method is the fill and empty purge method. Recent updates to industry sampling standards, such as GPA 2166 and API 14.1, recommend that the cylinder be preheated to a temperature above the hydrocarbon dew point of the flowing gas before the cylinder is used to collect a gas sample. If the cylinder is initially preheated, the heat generated from compression during the fill and empty cycles will keep the cylinder heated above the expected hydrocarbon dew point temperature. The GCH-300 provides a simple, efficient solution to cylinder preheating for spot sampling. It consist of the heater enclosure and a controller. To use the GCH-300, a cold empty cylinder is placed inside the heater enclosure and the controller cable is connected. Sample cylinder temperature is displayed while it is heated. When fully heated, the controller will keep the cylinder at the set temperature (140°F) until you are ready to disconnect the controller cable and take the sample. The hot cylinder stays in the heater enclosure until the sampling process is finished.