CGI-6 - 117,000 BTU Output Cast Iron Boiler, Spark Ignition - Series 4 (Natural Gas)

Weil‑McLain CGI‑6 – 158 MBH Cast‑Iron Water Boiler with Spark Ignition

The CGI‑6 is a robust, gas-fired cast-iron boiler engineered for hydronic heating in residential and light-commercial systems. Offering 158 MBH input and 117 MBH net I=B=R output, it achieves 84% AFUE. Designed for both natural gas and LP installations, it ships complete with Taco circulator and is compatible with multiple venting configurations, including natural draft and direct exhaust.

⚙️ Technical Overview & Contractor Benefits Fuel & Ignition & Inputs 158 MBH input → 135 MBH DOE output → 117 MBH net I=B=R 84% AFUE efficiency weil-mclain.com +14 ecomfort.com +14 afsupply.com +14 phwarehouse.com +3 supplyhouse.com +3 ussupply.com +3 Spark ignition; works with natural gas or LP (model variants available) Construction & Durability Cast-iron sectional heat exchanger, tested to 50 PSIG for resiliency Water content ≈3.3 gal; jacket accommodates optional low-water cutoff weil-mclain.com Pre-wired Taco‑007 circulator simplifies installation afsupply.com +2 ecomfort.com +2 weil-mclain.com +2 Venting & Service Access 5″ OD natural-draft vent collar; alternate induced draft options available Front access panel opens for easy burner/pilot servicing No draft hood or mechanical damper required; complies with sealed combustion standards ussupply.com +10 weil-mclain.com +10 weil-mclain.com +10 acwholesalers.com +3 weil-mclain.com +3 phwarehouse.com +3 Safety & Warranty ASME-rated 30 PSI relief valve and standard controls Residential heat exchanger warranty: 20 years; parts: 2 years (commercial: 10/1 years) weil-mclain.com +3 phwarehouse.com +3 s3.amazonaws.com +3 afsupply.com +1 s3.amazonaws.com +1 ???? Installation Considerations Mounting: Floor-mounted model with standard clearance requirements Combustion Air: Requires sufficient indoor or outdoor combustion air per local codes Controls Integration: Control module includes pilot assembly and diagnostic LED for easier fault identification s3.amazonaws.com +2 ecomfort.com +2 supplyhouse.com +2 weil-mclain.com +1 thefurnaceoutlet.com +1 Retrofit Ready: Fits existing baseboard, radiant, or panel radiator systems with minimal modifications ???? Contractor Summary The CGI‑6 delivers reliable, low-maintenance performance in high-capacity hydronic systems. Its cast-iron durability, efficient 84% AFUE, sealed combustion adaptability, and pre-installed circulator make it an excellent choice for jobsite versatility. The straightforward access design and diagnostic controls significantly reduce labor during installation and service calls.