Moss firetube scotch marine wood boilers are 2 or 3 pass dry back units ranging in size from 100 - 600 HP with design pressures from 15 - 300 PSIG. This boiler design can be supplied with either a Moss gasifier or pneumatic combustion system. The system is provided with a heavy duty frame for the combustor or gasifier/secondary allowing for complete construction with the boiler at our manufacturing facility. The firetube design allows for quicker installation time at the jobsite. The combustor/gasifier system is installed with 9" of castable refractory and 2" of 1900 F. insulating block. A forced draft fan is used to supply undergrate air for either a gasifier or pneumatic combustion system. A secondary fan supplies air to the plenum, as required, for a clean burning system. The secondary chamber is also provided with a cleanout door for ash removal during combustor/boiler downtime. Ash generally will drop out in areas where the gases change direction. All boilers are provided with skids and are designed to be installed on a foundation pad, concrete piers or structural steel. Our large firetube boiler furnaces provides the required combustion volumes for complete burnout and cooling of gases before the entrance into the second pass tubes. The large steam storage and disengaging area in the firetube boiler helps prevent drops in steam pressure and water carryover to the process. Large turnaround space at the end of the first pass helps prevent tube damage to rolled and welded boiler tubes. An automatic sootblower system is available as optional equipment and is strongly recommended for extended runtime between boiler tube cleanouts.