DrumPAK is ready to use as a single, two-element or three-element controller as standard; simply enable the desired strategy during controller setup. Furnace pressure (draft) control, fuel totalization and economizer monitoring are available as options. Modbus RS-485 communication is standard.              Data Sheet

Single-Element Control                                                     
This is an easy and economic way to upgrade on-off level control to continuous control to reduce wear and tear on feedwater pumps and motors, and ensure a more consistent control around setpoint on smaller boilers, boilers with slow load changes, or systems without steam flow measurement. Only level measurement is required. DrumPAK allows easy upgrade to two- or three-element control in the field simply by adding the measurement device and selecting the new control strategy.

Two-Element Control
With the addition of steam flow measurement, DrumPAK provides “shrink” and “swell” compensation and better response to load changes. The controller calculates the feedwater flow requirement based on level, and uses the Steam Flow signal from a flow transmitter or vortex meter as a feedforward signal to anticipate the effect of steam demand changes on level.

Three-Element Control
A three-element system adds measurement and control of feedwater, which allows the system to compensate for variations in feedwater pressure and
valve linearity. Variations in feedwater pressure result in significant changes in drum pressure, drum level and water temperature, causing the boiler to increase its firing rate and expend more energy as it attempts to recover full power. When set up for 3-element control, DrumPAK protects against this as well as reducing boiler trips due to unstable feedwater pressure. Large boilers or those with large or rapid load changes benefit most from a 3-element control system.