4WG means 4-pass Wet-back fire tube Boiler with Gun Burner in
Commercial
Similar to 4WG
AA - Anchor Assembly
AAC - Autoclave Aerated Concrete
AAC - Advanced Auto Clamp
AACTS - Automated Accelerated Characterization Test System
AAE - Advanced Action Engine
AAE - Atmospheric Air Ejector
AAFI - Air Assisted Fuel Injector
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