These MM9E compact units employ induced combustion, reliable hot surface ignition and high heat transfer aluminized tubular heat exchangers. The units are factory shipped for installation in upflow applications and may be converted for downflow applications. These furnaces are designed for residential mobile home, manufactured, or modular home installation. All units are factory assembled, wired and tested to assure safe dependable and economical installation and operation. The MM9E units are Category IV direct vent, sealed combustion listed and may be vented either through side wall or roof applications using approved plastic combustion air and vent piping.