Boiler Modulation Control

Why would you modulate the boiler firing rate.

Boiler modulation control.

Boilers with modulating firing controls are quite common. Most modern designs have a level of modulation embedded in their design. Unless the heat exchanger area and excess air ratio are exactly varied to match the firing rate an expensive and complicated proposition all boilers will exhibit similar characteristics. 4 all the burner management and combustion control systems can be tied into a single platform including the level control and the vfd drive s.

Modulating control improves boiler operation by monitoring the steam or hot water line to produce a continuous control signal that determines the fuel input. The type of control and balancing solution directly influences the precision of temperature control global flow and the pump head. The ratio of the low fire to high fire rates is defined as the boiler s turndown capability. On fan equipped boilers modulation is accomplished by reducing the air and gas flow into the boiler.

Reductions in steam pressure or water temperature lead to an increase in firing rate. Not only does this. The choice of control mode 2 way or 3 way valves and on off or modulating control influence directly the return temperature for the heat sources condensing boilers chillers heat pumps etc. Modulating control in a power plant is extremely important.

Modulating the feedwater flow to the boiler has so many advantages over on off feedwater addition it is difficult to visualize any other system. It is always advisable that the designer frame a basic control philosophy before developing a control loop. Boiler manufacturers commonly now have their own modulating thermostats that are also available as smart thermostats. Either with boiler units that have appropriate turn down or by using.

There are also exist independent smart control manufacturers such as nest and honeywell evohome that produce opentherm compatible modulating controls. Modulating the feedwater to the boiler is the most important part of the boiler feedwater system. This chapter discusses control loops as they relate to boilers dealing with the following issues. 4 with a plc based control system as shown in fig.

This easy to use boiler modulating control from weil mclain can control up to four modulating water boilers. The last value added option to consider with the modulating continuous system is a plc based control system.