Profile: CRG Boiler Systems offers boilers, burners, separators, fire pumps, water softeners, and hot air units. We offer a full line of scotch boilers, from 2 & 3 pass dry back boilers to 3 & 4 pass wet back boilers. The 2 & 3 pass dry-back boilers have features such as 12 X 16 manholes for 70 HP & UP units, insulated boiler shells, heavy-duty saddles and lifting lugs. The 4 pass wet back boiler has independent rear tube sheets. It has no refractory rear doors of baffles to crack.