Earlier this year we were asked to evaluate a chiller and determine if the machine was repairable or required replacement. A chiller is a refrigeration machine used to "chill" water which in turn is used to cool air. The air is then circulated to the spaces, such as offices, to be cooled. The chiller under evaluation was involved in a fire that resulted from a malfunction within the control section. Upon closer inspection, it was noted that the entire control section would require all new relays, terminal blocks, and wiring. It was further determined that both compressors had also been damaged and would require replacement. Along with compressor replacement, each refrigeration circuit would have to be flushed, evacuated, and recharged with new refrigerant. The condition of the chiller is shown in figures 1 through 3.
Fig 1 Fire damaged chiller
Fig 2 Hole burned in wall of control panel as a result of electrical arcing
Fig 3 One of two compressors damaged in fire
After ascertaining the condition of the chiller, prices were obtained from various sources for material and labor in order to evaluate rebuilding of the unit. Price and availability were also obtained from the original manufacturer on a new unit. It should be noted that the current unit was no longer manufactured. The price and availability that was obtained was obtained for a comparable unit. After determining that rebuilding the chiller would be more economical than a new unit, it was decided to pursue repair of the existing machine. In this case, time was critical and the repair of the chiller had to be completed as soon as possible. Normally, bids from mechanical contractors should be obtained and each proposal evaluated. However, the bidding process can take more time than can be tolerated by the insured. As a result, the insured's contractor, who was familiar with the damaged machine, was selected to rebuild the unit.
In summary, evaluation of repair or replacement of a machine should be done independently by an uninterested party. Bids should be obtained for equipment and labor but in those cases where time is a factor, competitive bidding has to be replaced by an independent estimate. Lastly, a mechanical engineer is in the perfect position to evaluate a repair versus a replacement, coordinate the bid process, and assist in the selection of a contractor.
