Boiler Control Upgrades Plus Regular Maintenance Can Improve Energy Efficiency
September 19, 2011
Today's tip comes from James Piper, contributing editor for Building Operating Management and Maintenance Solutions magazines: Focus on boiler controls to reduce energy use.
New boiler controls can provide major gains in energy efficiency, performance, and safety at a much lower cost than replacing boilers. Older-generation boiler controls used mechanical linkages. With age and use, linkages wear and go out of adjustment, reducing the unit's efficiency. Older-generation controls also suffer from offset, which occurs when the system operates close to, but not exactly at, the desired setting.
Today's boiler controls incorporate microprocessors, solid-state sensors, and independent servo motors, which give managers accurate and reliable operation, eliminating problems such as offset.
When evaluating control options, it is important to remember boiler controls perform three basic functions: combustion control; water-level control; and flame safeguarding. If a facility uses multiple boilers, the control system must perform a fourth function: sequencing. Facility managers must factor all of these issues into their control decisions. Three types of boiler controls to consider upgrading are flue gas trim, sequencing and automatic blowdown.
Getting the proper controls installed is only the first step in achieving efficient and reliable boiler operation. To keep things operating that way over the life of the system, technicians must properly maintain controls. But the importance of proper maintenance goes far beyond efficiency and reliability issues. It also incorporates safe boiler operation.
Technicians must keep logs for boiler operations, recording operating parameters frequently enough to identify trends. Equally important, they must review those logs regularly to actually detect the trends.
At least once each month, technicians must test a boiler's safety equipment, such as the safety-relief valve, water-level control, and low-water fuel cutoff, according to the boiler manufacturer's recommendations. Larger boilers require more frequent testing.
They also should test all controls for proper operation and calibration at least once annually, and they should inspect, clean, and lubricate mechanical linkages according to manufacturer directions.