Providing Boiler Tune-Ups for Multifamily Buildings, Efficiency Improvements and Contractor Training

Fourteen multifamily boilers in need of efficiency improvements received tune-ups from one of the Minneapolis Energy Office's (MEO) five multifamily program contractors. A primary purpose was to train these contractors to complete tune-ups using the proper equipment and techniques, and thereby to make this service more widely available. A survey of available equipment, capable of continuously measuring the parameters of combustion efficiency, was also completed. In addition, efficiency increases due to the tune-ups were measured and compared with predicted increases, and boilers were re-tested several months after the tune-ups to examine stability of the modifications.

Contractors were successfully trained and five service people are now certified to perform high-efficiency tune-ups as recommended through MEO's multifamily program. Research into available equipment has identified the three or four best options for those contractors who wish to complete these tune-ups as part of MEO's program.

Savings achieved as a result of tune-ups ranged from zero to 14% and averaged 3.9%. Savings among conversion boilers in which the modifications centered on reducing excess air, saved the most (5.5% on average), followed by savings among conversion boilers which required reductions in stack temperature (3.6% on average). Only one of the three gas-designed boilers achieved an efficiency increase, making average savings 1.2%. Paybacks for all cases ranged from .2 years to no payback, with a median payback overall of 1 year. The stability of these adjustments appears quite good, with an average change which was not statistically significant. Prediction methods for estimating tune-up savings were quite accurate for gas conversion boilers, and tended to overpredict savings for the one dual fuel conversion burner and for gas-designed boilers.

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Providing Boiler Tune-Ups for Multifamily Buildings, Efficiency Improvements and Contractor Training