Measuring only 78.2" high x 34" wide x 63.5" deep, the Benchmark S 4000 and 5000N (BMK4000/5000N) commercial condensing boiler features up to 15:1 turndown for energy efficiency, Low NOx emissions, and high reliability in an unmatched compact footprint that is up to half the size of any other four/five million BTU/hr boiler on the market. Incorporating AERCO’s field-proven stainless steel, fire-tube design, the BMK4000 and BMK5000N provides consulting-specifying engineers, facilities management, and building owners with a boiler that provides flexibility to fit in both retrofit and new construction installations.

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Features and Benefits

The Benchmark S 4000 and 5000N are the most efficient condensing boiler in an unmatched compact footprint that is up to half the size of other four/five million BTU/hr boiler on the market. Incorporating AERCO’s highly reliable, stainless steel, fire-tube heat exchanger, the Benchmark S 4000 and 5000N provides engineers, facilities management, and building owners with the flexibility to fit in both retrofit and new construction that require one or multiple 4000/5000 MBH boilers. 

• Durable 439 stainless steel fire tube heat exchanger
• Compact footprint
• Low operating, maintenance and installation costs
• Easy serviceability
• Up to 20:1 turndown ratio (5%)*
• Up to 98% efficiency
• Low NOx emissions 9 or 20 ppm or less at all firing rates
• Capable of variable primary flow installations
• Venting versatility with AL29-4C or Polypropylene
• Ducted combustion air capable
• Controls options:
• Constant setpoint
• Indoor/outdoor reset
• Remote setpoint
• 4-20mA signal or Modbus

*depending on capacity

Unmatched Modulation and Efficiency

Benchmark S water boiler is designed for condensing application in any closed loop hydronic system. It delivers unmatched burner modulation to match energy input directly to fluctuat­ing system loads to yield the highest possible seasonal efficiencies. And no other product packs as much capacity into such a small footprint.

Low Emissions

To minimize emissions, the Benchmark Series is fitted with a Low NOx burner whose emissions will meet the most stringent NOx and CO requirements. The fully modulating burner also maintains AERCO standards for energy efficiency, longevity, reliability and construction quality. The boiler can be field set for Ultra Low NOx emissions of 9 ppm.

Compact, Easy-to-Apply Design

With the smallest footprint in the industry and measuring only 78.2" high x 34" wide x 63.5" deep, the Benchmark S 4000 and 5000N easily fits through a standard size doorway overcoming the most challenging projects in the smallest mechanical rooms. Benchmark S boilers can be used as an individual unit or in modular arrangements and offers selectable modes of operation including constant set point, outdoor reset schedule or 4-20mA signal. For boiler plants ranging from 2-16 boilers, the AERCO Edge® built-in Boiler Sequencing Technology (BST) can be utilized. For heating plants greater than 16 boilers, AERCO Control System (ACS) provides the right solution for up to 32 boilers. Likewise, Benchmark S systems can be easily integrated with a facility-wide Energy Management or Building Automation System via Modbus.

Boiler Sequencing Technology (BST)

It requires less energy for a group of modulating boilers, each firing at “part load,” to heat a building, than for a single boiler operating at “full fire” to carry the entire workload. To meet building demand, the BST will employ as many boilers as available, each operating at its most efficient firing rate. Importantly, because the BST reacts in real-time to, up to 16 boilers, changes in the number of boilers available, users can take a unit offline for maintenance at any time or bring on back-up boilers for extremely cold conditions without changes to the BST. And as individual boilers are added or deleted, the energy delivered is automatically adjusted to prevent fluctuations in the header temperature of the plant.