Long-Lasting Comfort You Can Count On Bryant builds the Model 340MAV with components that are designed to offer consistent, long-lasting comfort that you can count on. The hot surface ignition starts this unit and keeps it operating with superior dependability. At the core of the Model 340MAV are the primary and secondary heat exchangers. These heavy-duty heat exchangers maximize heat transfer and resist corrosion so you can enjoy consistent, energy-efficient comfort season after season.  1. Primary Three-Pass Heat Exchanger Maximizes heat transfer with Bryant's unique S-shaped design. Made of durable, aluminized steel for years of worry-free comfort. 2. Secondary Condensing Heat Exchanger Extends heat transfer for even higher efficiency. It is protected by our Everlastic™ coating for long-lasting durability and corrosion resistance. 3. Sealed Combustion System Reduces drafts by using outdoor air for combustion. Seals in noise for quiet operation. 4. High-Efficiency Blower Features a direct-drive motor that operates with precision to deliver quiet, dependable heating. 5. Control Center Safely monitors furnace operation for peak performance and energy efficiency.