38459756 is an OEM Ingersoll Rand replacement hot gas bypass valve was used on their D300IN and D360IN refrigerated air dryers. This attaches to the inside of the dryer to sense the temperature of the refrigerant. If the temperature gets too low this will exert hot gas to prevent freezing. Often times this part is listed on the manual as "VB"
This hot gas bypass valve (HGBV) was used on the following Ingersoll Rand refrigerated air dryer: