EFTA01092129.pdf

Commercial & Industrial HVAC Systems • Campine Service Contracts • 24 Hour Emergency Service 43-15 36th Street Long Island City New York 1 1 101 vvww.adwinstonservice.com servile G' 04.02.13 Dear Mr. Barnett, In receipt of your request to cancel the multi stack chiller, we are currently waiting to hear from the factory, to see if any charges will be incurred from cancellation. However, let me point out the following benefits for proceeding with this project: The existing multi stack chiller consists of 4 compressors, which operates on demand to maintain desired chilled water temperature. These compressors are controlled by a central chilled water controller; under normal conditions the chiller will operate 1-3 compressors. As outdoor temperature increases, during hot summer weather, the fourth compressor will be used at times. Under extreme conditions temperatures from 95 degrees and above, the 4O ton carrier must be started, through the BMS system. This 40 ton chiller is approximately 25 years old, and has very poor efficiency rating — approximately 2 KW per ton or higher. By removing this inefficient chiller, and adding a new 30 ton multi stack module, to the existing multi stack, you will increase the efficiency rating to 1.1KW per ton. More importantly, you will now have 6 compressors fully integrated into the multi stack chilled water control system. This will give you complete and automatic redundancy. Also, if there are any compressor failures in any module, the controller will automatically bring on additional compressors to compensate for it. There would be no need for the BMS system to be involved, to open any valves and start the chiller. I have reviewed this project with one of our design engineers, who were involved when we installed the original multi stacks. He believes that this is one of the better designs, he has ever seen in a residence. If there are any issues in the house in specific areas, this should be treated separately, as there are different air handlers, for different areas. Chiller systems are the most reliable and have the lowest failure rate, whereas DX systems have many more components, controls, and compressors, along with a greater rate of failure. As you know, we installed the original equipment in this residence; therefore we are extremely familiar with it. I strongly recommend you reconsider the cancellation of the chiller. If you have any concerns and or/problems, please feel free to discuss them with me. Very truly ur h el A. dino Vice President EFTA01092129