Air assisted enclosed combustion device

An enclosed combustion device, comprising:

• a housing comprising an outer housing and a burner housing, the burner housing situated inside the outer housing and separated from the outer housing by an air gap;
• a temperature sensor and an exhaust gas oxygen sensor mounted to and extending inside the burner housing;
• a burner assembly mounted inside the burner housing for burning a fuel, the burner assembly having a burner, a fuel-air mixing nozzle connectable to a source of the fuel, an air tube connecting the burner and the fuel-air mixing nozzle, a fuel supply pressure sensor, a variable speed blower motor, a variable frequency drive (VFD) connected to the variable speed blower motor, and an air intake plenum connecting the variable speed blower motor and the fuel-air mixing nozzle;
• and
• an electronic control module having a processor and a non-transitory computer readable memory storing logic, the electronic control module in communication with the VFD, the temperature sensor, the exhaust gas oxygen sensor, and the fuel supply pressure sensor;
• wherein the logic of the electronic control module is configured to receive input signals from the VFD, the temperature sensor, the exhaust gas oxygen sensor, and the fuel supply pressure sensor and cause the processor to calculate an actual fuel-air ratio using the received input signals, cause the processor to compare the actual fuel-air ratio to a fuel-air ratio setpoint, and cause the processor to send a signal to the VFD to cause the VFD to adjust a blower speed of the variable speed blower motor to control a rate and volume of air from the variable speed blower motor to the fuel-air mixing nozzle if the actual fuel-air ratio and the fuel-air ratio setpoint are different.

An enclosed combustion device, comprising:

• a housing comprising an outer housing and a burner housing, the burner housing situated inside the outer housing and separated from the outer housing by an air gap;
• a temperature sensor mounted to and extending inside the burner housing;
• a burner assembly mounted inside the burner housing for burning a fuel, the burner assembly having a burner mounted inside a burner chamber, an exhaust gas oxygen sensor mounted to and extending inside the burner chamber, a fuel supply line, a fuel supply pressure sensor installed in the fuel supply line, an air plenum, a fuel-air mixing nozzle, an air tube connecting the burner and the fuel-air mixing nozzle, a variable speed blower motor connected to the air plenum, a variable frequency drive (VFD) connected to the variable speed blower motor, and an ambient air intake concentrically surrounding and extending at least partially over the fuel-air mixing nozzle to draw ambient air around the fuel-air mixing nozzle and into the air tube;
• and
• an electronic control module having a processor and a non-transitory computer readable memory storing logic, the electronic control module in communication with the VFD, the temperature sensor, the exhaust gas oxygen, and the fuel supply pressure sensor;
• wherein the logic of the electronic control module is configured to receive input signals from the VFD, the temperature sensor, the exhaust gas oxygen sensor, and the fuel supply pressure sensor and cause the processor to calculate an actual fuel-air ratio using the received input signals, cause the processor to compare the actual fuel-air ratio to a fuel-air ratio setpoint, and cause the processor to send a signal to the VFD to cause the VFD to adjust a blower speed of the variable speed blower motor to control a rate and volume of air from the variable speed blower motor to the fuel-air mixing nozzle if the actual fuel-air ratio and the fuel-air ratio setpoint are different.