Green Mountain 16B515003100204 GMGS 150 Input MBtu - 82% AFUE Natural Gas Steam Boiler - Chimney Vent

Dependable Cast Iron Heat Exchanger with Cast
  Iron Push Nipples. The Sections and Push Nipples
  expand at the same rate when heated. By using
  similar materials instead of less expensive gaskets
  the boiler maintains a water tight seal over time.

LWCO (Probe Type), Pressure High Limit Control,
  Pressure Gauge, Gauge Glass.

Atmospheric Chimney Vent Boiler with Integral
  Draft Hood and Vent Damper. Low profile compact
  design makes it ideal for low clearance
  installations.

Brass/copper pig tail siphon for long life.

10 Year Limited Warranty (Residential
  Applications).

Electronic Low Water Cut-Off with 3/4” Probe

Pressure Limit Control

Steam Pressure Gauge and Glass Water Level
  Gauge

Completely installed and wired gas control system

Titanium Composite Burners

Gas Manifold with Orifices

Automatic Redundant Combination Gas Valve

24 Volt

with Pilot Filter and Regulator

Intermittent Pilot Control

Continuous Retry 100% Shut-Off

Combination Pilot Burner/Electrode/Flame Sensor
  and Integral Draft Diverter

Cast Iron Sections with Cast Iron Push Nipples

24 Volt Transformer

Flame Roll-Out Safety Shut-Off Fuse Link (Roll-
  Out Switch) and Blocked Vent Safety Shut-Off
  Manual Reset Disc Thermostat (Spill Switch)
  with Spare Fuse Link included

Assembled Boiler with Insulated Jacket

3/4” Boiler Drain Valve

15 psi ASME Pop Safety Valve

(2) 2 1/2” Supply Tappings and (2) 2 1/2” Return
  Tappings (2) 2 1/2” Square Head Pipe
  Plugs - to plug unused supply and return tappings