Low Temp Heating Mod-Con Boilers (Great For Radiant Floor Heat)
A Mod-Con (Modulating Condensing) Boiler will modulate water temperature according to the outdoor temperature. Modulating the BTU output to suit indoor needs, automatically adjusting to provide optimum efficiency and comfort.
Weil-McLain Evergreen Hi-efficiency Condensing Boiler

- Stainless Steel Fire Tube Heat Exchanger with non-metallic base
- Floor Standing Boiler with optional wall mount kit
- Available in 6 Sizes: 70, 110, 155, 220, 299, 399 MBH
- Modulating Condensing Boiler
- 95% AFUE (70-299); 96.5% Combustion Efficiency (399)
- 4 Pump/Auxiliary Outputs (Example: 1 boiler loop pump +3 zone pumps)
- Up to 8 Multiple Boiler Control with lead/lag rotation
- Modbus® to BMS connectivity
- Each input can be assigned to a priority (Up to 3 Priorities)
- Multiple Inputs can be assigned one priority (Zone Based Control)
- All Lag Boiler Inputs and Output can be used
- 0-10 Volt Input (modulation or set point)
- Configurable Auxiliary Input/Output System
- Boiler Circulator Included (ECM version with 70-155)
- Fire tube stainless steel heat exchanger
- Integrated precision control
- Advanced multi-zone capacity
- ENERGY STAR® Most Efficient 95% AFUE* rating
- Set-up wizard for easy install
- Floor standing and wall-hung capable
Weil-McLain Ultra S4 Gas Low Temp Condensing Boiler

Cast aluminum coated heat exchanger
Up to 94% DOE AFUE efficiency
Designed to operate in low temperature condensing applications
Outdoor reset and domestic hot water priority
Modulates with 5:1 turn-down ratio
High grade stainless steel burner features quiet operation
U-Control gives you the power for easy set-up and maintenance:
Multiple set-up and zone options
System sensing recognizes system and outdoor temperatures
Temperature management for up to three different set-points
Control multiple boilers from a single control panel
Standard screen messages provide service alerts and maintenance reminders
Weil-McLain Eco Gas Low Temp Condensing Wall Mount Boiler
Class-leading 70,000, 110,000, and 155,000 BTUH models
Exceeds Energy Star requirements at 95% AFUE efficiency rating
Durable stainless steel fire tube heat exchanger
Streamlined design configurable for installation
Display can be mounted on the boiler or wall (up to 2’ away)
Components positioned for fast and easy service
Multiple vent configurations and material options
Optional accessories to match virtually any installation
Navien NHB-80 Gas Low Temp Condensing Wall-Hung Boiler
HIGH EFFICIENCY CONDENSING HEATING BOILER
Max Input: 80,000 BTU/H
Indoor wall-hung
Residential/Commercial
- Super condensing efficiency
- Dual stainless steel heat exchangers
- SCH40, 2″ PVC venting up to 60′
- ½” Gas pipe up to 40′
- TDR up to 10:1
- Integrated controls
Navien NHB-110 Gas Low Temp Condensing Wall-Hung
HIGH EFFICIENCY CONDENSING HEATING BOILER
Max Input: 110,000 BTU/H<
Indoor wall-hung
Residential/Commercial
- Super condensing efficiency
- Dual stainless steel heat exchangers
- SCH40, 2″ PVC venting up to 60′
- ½” Gas pipe up to 40′
- TDR up to 11:1
- Integrated controls
Navien NHB-150 Gas Low Temp Condensing Wall-Hung Boiler
- Super condensing efficiency
- Dual stainless steel heat exchangers
- SCH40, 2″ PVC venting up to 60′
- ½” Gas pipe up to 40′
- TDR up to 15:1
- Integrated controls
