Triangle Tube Keystone 399,000 BTU Output Condensing Boiler - KS 399

Keystone Boilers provide promising solutions for large residential and light commercial applications. The Triangle Tube Keystone KS 399 carries a stainless steel heat exchanger with a thermal efficiency of 96.5%. The compact construction reduces needed floor space and the cabinet provides quick access to all components. To make set-up easy, there is a large user friendly interface. To maximize service life and efficiency, up to 8 boilers can be joined in a cascade.

• 160 psi maximum working pressure
• 75 psi (517 kPa) ASME Rated pressure relief valve
• 5 to 1 turndown ratio
• Stainless steel heat exchanger (no gaskets)
• Vertical or horizontal direct vent
• Holds, alerts, and errors notifications
• Sealed combustion chamber
• Built-in condensate trap
• Vent temperature cutoff
• Direct spark ignition
• Outdoor reset -custom reset curves, domestic hot water priority, warm weather shutdown

Installation & Warranty Information

We suggest that the installation of any Triangle Tube boiler or water heater to be completed by a licensed technician with the proper knowledge.

Triangle Tube does not accept service or warranty calls from anyone other than a licensed technician. If you have any issues with installation or the initial startup, contact your technician to contact us or the manufacturer.

Neither us or Triangle Tube are held liable for wrongful installation and operation. An installation receipt as well as a sales receipt is required to have the warranty honored when needing replacement parts.