IBC Technologies EX-850-NG Condensing Boiler 850 Input MBH, AFUE 97%, Direct Vent, Natural Gas

Unparalleled build quality

Turndown ratio of 10:1 means you have the power
  to heat the building in the coldest weather, yet
  reduce short cycling when the weather is mild

MFZ Moisture management protocol

Reverse flow detection

Outdoor reset control of water temperature

CSA/UL approved low water cut-off and manual
  reset high limit

CSD-1 Compliant

Unmatched safety features

The most advanced stainless steel fire tube boiler
  on the market today

High grade 439 stainless steel construction

Innovative saddle-bolt lit hardware

Better thermal efficiency - up to 97%

Condensed flue gasses clean vertical flue tubes
  while draining

Custom water flow baffling to ensure even heat
  transfer and long life

PVC/CPVC/PP/SS venting materials approved

Available in either NG or LP factory set or field
  convertible

Direct vent lengths – up to 170’ each side

Open access to heat exchanger and all internal
  components

Express setup - program your boiler in seconds
  with remote monitoring & diagnostics

Precise burner modulation control

Easy USB programmability

Intuitive alert system with detailed error message

Vast array of performance data for troubleshooting

Load combining and zoning

Multi-boiler communication for network
  applications up to 24 boilers without additional
  controls

With 24 networked boilers turndown ratio is 240:1

End switch, 0-10 VCD or 4-20mA control
  compatible

Full BACnet capability included

Primary pump and zone pump controller - up to 4
  zones