From inside (document excerpt):
Primary Cell Outlet Panel Kit Cancels: IIK 340M-40-21 IIK 340M-40-26 11-96 Installation Instructions Part No. 320726-751, -752, -753, -754, -755, and -756 NOTE: Read the entire instruction manual before starting the installation. This symbol indicates a change since the last issue. SAFETY CONSIDERATIONS Installing and servicing of heating equipment can be hazardous due to gas and electrical components.
Only trained personnel should install or service heating equipment. Untrained personnel can perform basic maintenance functions such as cleaning and replacing filters. All other operations should be performed by trained service personnel. When working on heating equipment, observe precautions in the literature, on tags, and on labels attached to the unit. Follow all safety codes. Wear safety glasses and work gloves. Have a fire extinguisher available. Recognize safety information. This is the safety-alert symbol. When you see this symbol on the furnace and in instructions or manuals, be alert to the potential for personal injury. Understand the signal words DANGER, WARNING, and CAUTION. These words are used with the safety-alert symbol. DANGER identifies the most serious hazards which will result in severe personal injury or death. WARNING signifies a hazard which could result in personal injury or death. CAUTION is used to identify unsafe practices which would result in minor personal injury or product and property damage. Turn off gas and electrical supplies to unit before beginning any installation or modification. Follow the operating instructions on label attached to furnace. Failure to follow this warning could result in electrical shock, fire, personal injury, or death. Label all wires prior to disconnection when servicing controls. Wiring errors can cause improper and dangerous operation. INTRODUCTION This instruction covers installation of the primary cell outlet panel kit Part No. 320726-751, -752, -753, -754, -755, and -756 in multipoise, 40-in. tall, condensing gas furnaces. NOTE: A releasing agent such as PAM cooking spray or equivalent (must not contain corn or canola oil, aromatic or halogenated hydrocarbons) and RTV sealant (G.E. 162, G.E. 6702, or DowCorning 738) are needed before starting installation. DO NOT substitute any other type of RTV sealant. G.E. 162 (P771-9003) is available through RCD in 3-oz tubes.