
Heat Exchanger | Stainless Steel Firetube Heat Exchanger |
---|---|
Size Range | 850 - 6,000 MBH |
AHRI Boiler Efficiency | 96.8% |
Turndown | Up to 10:1 |
Application | Variable Volume, Full Flow, Primary / Secondary |
FlexCore Symmetrical Firetube boilers bring hydronic heating products to unprecedented levels of operating efficiency.
Unlike other manufacturers; from start to finish the FlexCore was designed, developed and engineered by the experts at RBI.
Engineered for performance and longevity the FlexCore utilizes a perfectly temperature balanced heat exchanger that provides not only the highest efficiencies but also a durability beyond that of any competitive firetube boiler on the market.

features and benefits
- 850 - 6,000 MBH
- 96.8% AHRI Certified Efficiency
- Full Modulation (up to 10:1)
- O2 Monitoring
- Stainless Steel Symmetrical Firetube Heat Exchanger (160 psi)
- Variable Volume, Full Flow and Primary/Secondary
- Patented "Turbo Pilot" Sure-fire Ignition
- Sika Vortex Flow Sensor
- HEATNET 3.0 Integrated Control Platform
- Touchscreen Programming & Diagnostics
- Modbus, LonWorks and BACnet BMS Integration
- Symmetrically Air/Fuel Coupled
- Category II and IV (up to 160’)
- PVC/CPVC, Polypropylene and Stainless Steel Vent Approved
- Warranty (Heat Exchanger): 10-years
- Superior Durability
- Easy Installation & Maintenance
- Fits through 36" Door
- Low Nox
flexCore Dimensions and ratings
Input | Boiler | Output | Unit | Depth | Unit | Width | Unit | Height | ||
---|---|---|---|---|---|---|---|---|---|---|
Size | MBH | kW | MBH | kW | In. | mm | In. | mm | In. | mm |
850 | 850 | 249 | 812 | 238 | 70 | 1778 | 32 | 812.8 | 80 | 2031.9 |
1000 | 1000 | 293 | 955 | 280 | 70 | 1778 | 32 | 812.8 | 80 | 2031.9 |
1500 | 1500 | 440 | 1426 | 418 | 70 | 1778 | 32 | 812.8 | 80 | 2031.9 |
2000 | 1999 | 586 | 1901 | 557 | 72.4 | 1838.3 | 32 | 812.8 | 80 | 2031.9 |
2500 | 2500 | 733 | 2397 | 703 | 72.4 | 1838.3 | 32 | 812.8 | 80 | 2031.9 |
3000 | 3000 | 879 | 2904 | 851 | 72.4 | 1838.3 | 32 | 812.8 | 80 | 2031.9 |
3500 | 3499 | 1025 | 3327 | 975 | 109.4 | 2770.7 | 34 | 863.8 | 80 | 2031.9 |
4000 | 3998 | 1172 | 3802 | 1114 | 109.4 | 2770.7 | 34 | 863.8 | 80 | 2031.9 |
4500 | 4500 | 1319 | 4329 | 1269 | 109.4 | 2770.7 | 34 | 863.8 | 80 | 2031.9 |
5000 | 5000 | 1465 | 4795 | 1405 | 109.4 | 2770.7 | 34 | 863.8 | 80 | 2031.9 |
6000 | 6000 | 1758 | 5808 | 1702 | 109.4 | 2770.7 | 34 | 863.8 | 80 | 2031.9 |
Cat IV Positive | Cat II | Air Intake | Connections | Shipping | Weight | ||
---|---|---|---|---|---|---|---|
Size | UL Listed SS** | Negative** | Gas Nat | Water | Lbs | Kg | |
850 | 5" | 8" | 6" | 1" | 3" | 1515 | 687 |
1000 | 5" | 8" | 6" | 1" | 3" | 1515 | 687 |
1500 | 6" | 8" | 8" | 1-1/2" | 3" | 1555 | 705 |
2000 | 6" | 10" | 8" | 1-1/2" | 3" | 1880 | 853 |
2500 | 8" | 12" | 8" | 1-1/2" | 3" | 1955 | 887 |
3000 | 8" | 12" | 8" | 1-1/2" | 3" | 2055 | 932 |
3500 | 10" | 12" | 10" | 2-1/2" | 4" | 3420 | 1551 |
4000 | 10" | 12" | 10" | 2-1/2" | 4" | 3745 | 1699 |
4500 | 10" | 14" | 10" | 2-1/2" | 4" | 3600 | 1633 |
5000 | 12" | 14" | 12" | 2-1/2" | 4" | 3920 | 1778 |
6000 | 12" | 14" | 12" | 2-1/2" | 4" | 4150 | 1882 |
**Diameters may vary based on system design
Literature