Addendum to P97595 (Controls Sequencing).docx

Addendum to P97595 System Controls and Sequencing The Chilled Water System Equipment shall operate according to the following control Sequence:

1. On-Off control of the individual water chillers shall be dependent on water temperature in the chilled water buffer tank WT-1. The water chillers shall be staged based on tank water temperature as follows:

a. WC-1 shall turn on when tank water temperature rises to 45 degrees Fahrenheit, and shall turn off when tank water temperature reaches 40 degrees Fahrenheit.

b. WC-2 shall turn on when tank water temperature rises to 49 degrees Fahrenheit, and shall turn off when tank water temperature reaches 45 degrees Fahrenheit.

c. WC-3 shall turn on when tank water temperature rises to 53 degrees Fahrenheit, and shall turn off when tank water temperature reaches 49 degrees Fahrenheit.

d. WC-4 shall turn on when tank water temperature reaches 57 degrees Fahrenheit, and shall turn off when tank water temperature reaches 53 degrees Fahrenheit.

2. Water Tank Temperature shall be determined for paragraph 1 requirements via a sensor located in the 8” diameter steel piping between the tank exit and the pump suction manifold.

3. Controls for water chiller on-off shall be adjustable or re-programmable to allow for adjustment of the on-off temperatures.

4. In order to equalize hours of operation between water chillers WC-1 through WC-4, the system controls for water chiller on-off shall allow for rotation of the various water chillers in the sequence shown above. In other words, in paragraphs 1.a through 1.d above, “WC-1”, “WC-2”, “WC-3”, and “WC-4” shall be capable of substituting for each other, to allow for the rotation of water chillers through the various water temperature ranges. The control system shall be capable of making such rotations/substitutions automatically, and without manual intervention to maintain equal operating hours between water chillers.

5. While water chillers WC-1 and WC-2 are existing and already have internal pumps for water circulation, water chillers WC-3 and WC-4 will be purchased new and without internal pumps. The pumps for water circulation through WC-3 and WC-4 shall be external to WC-3 and WC-4, and shall be located on the shop floor as shown in the attached drawings (reference pump CP-1 for WC-3 and CP-2 for WC-4). Contractor shall determine, provide and install all necessary controls to facilitate pump operation for circulation pumps CP-1 and CP-2, and to coordinate pump operation with that for their respective water chillers. CP-1 and CP-2 shall operate automatically in coordination with WC-3 and WC-4 respectively.

6. Circulation pumps CP-3 through CP-10 shall circulate water flow directly from storage tank WT-1 to the various generator test stands as shown in the attached drawings. On-off control for circulation pumps CP-3 through CP-10 shall be manual, and shall be accomplished via electrical switches located near the respective test stands. Switches shall be activated by the operators of the generator test stands on an as-needed basis. Individual switches, as well as their locations and wiring shall be as shown in attached electrical drawings. Switches and wiring shall be purchased and installed by Contractor.

Contractor shall determine and provide all necessary equipment, electronics, and software to accomplish the above requirements.