Standard Features - Factory Installed Hydrojet Total Performance System - Vitraglas lining - 3/4" NPT factory installed dielectric waterway fittings - 3/4" NPT side connections for space heating - T&P valve included - Brass drain valve - 2" Non-CFC foam insulation, 1" on PDX-2-65T - Optional concentric vent kit terminationv - Vertical or horizontal venting - Flammable vapor sensor - Honeywell Self Diagnostic Electronic Control - Closed Combustion - Powerful blower motor - Spark-to-pilot ignition