The problem: The existing burners were outdated with Saacke digital modulation systems fitted, which are now obsolete and unsupported.
The Solution: JBC proposed to retrofit the Ecosafe digital burner modulation system with touchscreen control panels to the existing Saacke gas fired burners, fitted to the Cochran Calpac hot water package boilers.
One of the main advantages is that the Ecosafe system would operate with its own fully adjustable PID pressure control and would accept a remote set point input (4-20mA). The controller would be installed within a new control panel with the touchscreen mounted to the front and incorporating the existing level controllers and supplementary wiring. The controller would replace the existing burner control.
The proposed system would virtually eliminate any inherent hysteresis by controlling the air and gas servos to 0.1 of a degree and running self-checks to ensure repeatability without any drift. Due to a tighter level of gas/air ratio control, the burner would operate at lower oxygen levels with an increased turn down ratio, achieving substantial fuel savings. There would also be massive savings made in electrical running costs due to the VSD optimising the FD fans speed to match the burner’s modulation.
All existing boiler interlocks /controls were retained and electrical drawings were submitted for approval.
The Savings: The existing burners were fitted with variable speed drives, which will provide significant electrical savings. The motor size for the burners is 15kW
Over the course of a year, burners with a higher turndown will spend large portions of time between low and high fire, providing scope to save (at minimum) 50% electrical power from the combustion air fan.Burners with a good turndown will take advantage of this potential. Each time the boiler purges, the motor is running at full speed consuming the maximum power output of the motor
Installing digital control and variable speed drive would typically yield fuel savings of at least 5%. This estimate is based on a combination of lower excess oxygen levels, lower flue gas temperatures at low fire and an increase in turndown.