• High heat exchanger condensing efficiency
• Modulation down to 20% of full fire (5:1 turndown)
• Sealed combustion chamber
• Pre-mix stainless steel burner
• Low NOx system exceeds the most stringent regulations for air quality – 10 ppm NOx
• Horizontal or vertical direct vent
• Horizontal vent and air terminals
• Vent and air pipe lengths of up to 100 equivalent feet (each)
• Built-in condensate trap
• Vent temperature cutoff feature
• Direct spark ignition system
• Indirect water heater priority
• Sensor for indirect domestic water tank
• 160 psi maximum working pressure
• Stainless steel heat exchanger with welded construction (no gaskets)
• ASME "H" stamp
• 75 psi (517 kPa) ASME rated pressure relief valve
• Water flow switch
• Temperature & pressure gauge

Triangle Tube's Keystone Series Condensing Boilers are designed for large residential and light commercial applications. The stainless steel heat exchanger and burner provides high efficiency, low emissions, and a high turndown to minimize short cycling. With maximum inputs of 850 MBH for boilers and 500 MBH for water heaters, the Keystone series can meet most needs with a single unit. For larger requirements the advanced control allows units to be joined and function with parallel modulation for maximum efficiency.

Triangle Tube Boiler Installation & Warranty Information

We recommend that the installation of all Triangle Tube Boilers and Water heaters be done by a licensed, trained and qualified technician with the proper knowledge and background.

Should you experience an issue during the installation or the initial startup of the unit, please do not contact the manufacturer. You should have the technician that installed the unit contact either us or the manufacturer. Triangle Tube cannot accept any service or warranty calls from anybody but a licensed technician.

Neither we or Triangle Tube can be held liable for improper installation and operation of any Triangle Tube boiler product purchased from our company. Should a warranty issue arise where parts will need to be replaced, an installation receipt will be required along with your sales receipt. Failure to provide a receipt or invoice may result in the warranty not being honored.