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Williamson-Thermoflo Products

Williamson-Thermoflo GWA210

GWA-210-NS Standing Pilot Gas Cast Iron Boiler 80.5% - 210,000 BTU


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Discontinued No longer available.

The Williamson-Thermoflo GWA series boiler are chimney vented and can used with natural or propane gas. They are designed to be used with all kind of radiators and radiant floor heating systems. Thanks to the durable cast iron sections the GWA series boilers are proven to last for decades. The GWA series boilers are made for most residential applications and with sizes from 52,000-245,000 BTUs we have the right unit for you. Available at AppliancesConnection


  • One-piece access door.
  • Insulated Extended Steel Jacket.
  • Cast Iron Section s w ith Built-in Air Separator.
  • Circulator & Near Boiler Piping.
  • Pressure Temperature Gauge.
  • Safety Relief Valve.
  • Drain Valve.
  • High Limit.
  • Circulator Pump Relay.
  • Transformer and Junction Box.
  • Automatic Vent Damper.
  • 120V Power switch
  • 100% Shut-off Combination.
  • Non-Linting Pilot Burner.
  • Stainless Steel Burners.
  • Vertical Drafthood
  • Blocked Vent Limit Switch.
  • Flame Roll-Out Switch
  • Factory tested.


  • Heating BTU/h: 210,000
  • AFUE: 80.5%
  • DOE Heating Capacity MBH: 168,000
  • NET I=B=R MBH: 151,000
  • Heat Exchanger Type: Cast Iron
  • Venting Material: Single Wall Galvanized Pipe
  • Vent Application: Chimney
  • Recomended Chimney Size: 7"
  • Applications: Hot Water
  • Water Content (Gal.): 3.8
  • Power Supply Voltage/Frequency/Phase: 115/60/1
  • Maximin Fuze Size (Amp): 15
  • Water Supply/Return Connections: 1-1/4"
  • Gas Connection: 3/4"
  • Weight (Lbs): 370
  • Boiler Pump Included: No
  • Outdoor Sensor Included: No
  • Modulating: No
  • Fuels Type: Natural Gas or Propane
  • Unit Dimensions DxWxH (Inches): 23-1/4 x 22 x 62-1/8

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  • Brand:Williamson-Thermoflo
  • SKU:GWA210
  • Stock Id:256184
  • Product Number:GWA210


  • Modulating:No

    Technical Details

  • Energy Star:No
  • Construction:Cast Iron
  • Weight (lbs):370
  • AFUE:80.5%
  • Power Supply Voltage/Frequency/Phase:115/60/1
  • Gas Connection:3/4"
  • Heating BTU/h:210,000
  • DOE Heating Capacity MBH:168,000
  • NET I=B=R MBH:151,000
  • Heat Exchanger Type:Cast Iron
  • Venting Material:Single Wall Galvanized Pipe
  • Vent Application:Chimney
  • Recomended Chimney Size:7"
  • Applications:Hot Water
  • Water Content (Gal.):3.8
  • Maximin Fuze Size (Amp):15
  • Water Supply/Return Connections:1-1/4"
  • Boiler Pump Included:No
  • Outdoor Sensor Included:No
  • Fuels Type:Natural Gas or Propane
  • Unit Dimensions DxWxH (Inches):23-1/4 x 22 x 62-1/8
  • Weight:370.00 lbs