Modine's PDP power vented unit heaters are inexpensive to install, easy to use and offer excellent in-service economy. 83% thermal efficiency, maximizing seasonal efficiency through the use of a collector box and the power exhauster. A power exhaust can rotate 180 degrees allowing the unit to be vented vertically or horizontally. A 100% shut-off if the unit does not light, to ensure that unburned gases do not build up in the unit. An intermittent pilot-ignition system with continuous retry to keep the unit from locking and needing to be rest if the unit does not light on the first try. All PDP/BDP units may be field-converted from natural gas to propane if desired. A safety pressure-switch monitors the vent pipe to assure flue gases leave the building and do not back up in the space. Designed to utilize the smallest-diameter vent pipe possible. Wing screws so that the bottom pan can be dropped without a screwdriver or nut driver. A level hanging mechanism for easy field adjustments after adding accessories that may change the unit's center of gravity.