SPX Cooling Technologies 98-1514E user manual Acceleration time of 30 seconds per hour

Operation

order to prevent damage to the tower components.

4.Air flow rate: Reducing air flow through the tower causes the cold water temperature to rise. This is the approved method by which to control leaving water temperature.

If your tower is equipped with a single-speed motor, the motor may be shut off when the water temperature becomes too cold. This will cause the water temperature to rise. When the water temperature then becomes too warm for your process, the motor can be restarted.

Caution	When operating in this mode care must be taken not to exceed a total
	acceleration time of 30 seconds per hour.

Fan cycling limits: From a dead stop, determine the number of sec- onds it takes the fan to arrive at full speed. Divide this number into 30 to determine the allowable number of starts per hour. Considering the normal fan and motor sizes utilized on AV Series towers, anticipate that approximately 4 to 5 starts per hour are allowable.

If your tower is equipped with a two-speed motor, you will enjoy greater opportunity for temperature control. When the water temperature becomes too cold, switching the fan to half-speed will cause the cold water temperature to rise—stabilizing at a temperature a few degrees higher than before. With a further reduction in water temperature, the fan may be cycled alternately from half-speed to off—subject to the same constraint of 30 seconds of allowable acceleration time per hour as outlined above.

If your tower consists of two or more cells, cycling of motors may be shared between cells, increasing your steps of operation accordingly.

For greater insight on cold water temperature control, please read “Cooling Tower Energy and its Management”, Marley Technical

Report #H-001-A, available at spxcoolling.com.

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