This workbook is part three of a self-instructional course prepared for the United States Environmental Protection Agency. The student proceeds at his own pace and when questions are asked, after answering, he either turns to the next page to check his response or refers to the previously covered material. The purpose of this course is to prepare the student for his APC Training Certificate. This workbook is concerned with troubleshooting to find out if the oil temperature on the boiler is correct. (BT)