SPX Cooling Technologies Fluid Cooler Marley MC - Manual (Page 14)

14
The fluid cooler establishes only the cold process fluid temperature
attainable under any operating circumstance.
2. air wet-bulb temperature: Cold process fluid temperature will also
vary with the wet-bulb temperature of the air entering the fluid cooler.
Reduced wet-bulb temperatures will result in colder process fluid
temperatures. However, the cold process fluid temperature will not
vary to the same extent as the wet-bulb. For example, a 20°F reduc-
tion in wet-bulb may result in only a 15°F reduction in cold process
fluid temperature.
3. Fluid flow rate: Increasing the process fluid flow rate (GPM) will cause
a slight elevation in cold process fluid temperature, while reducing the
fluid flow rate will cause the cold process fluid temperature to decrease
slightly. However, at a given heat load (see formula on page 13), pro-
cess fluid flow reductions also cause an increase in the incoming hot
process fluid temperature and thermal range.
Under no circumstances should the recirculation water pump(s) be
cycled to control process fluid temperature. Doing so may result in
excessive and premature scaling on the coil exterior surface. It is
recommenced that while process fluid is being circulated through
the coil the fluid cooler recirculation water system always be in op-
eration.
4. air flow rate: Reducing air flow through the fluid cooler causes the cold
process fluid temperature to rise. This is the recommended method
by which to control leaving process fluid temperature.
If your fluid cooler is equipped with a single-speed motor, the motor
may be shut off when the process fluid temperature becomes too
cold. This will cause the process fluid temperature to rise. When the
fluid temperature then becomes too warm for your process, the motor
can be restarted.
When operating in this mode care must be taken not to exceed a total
fan 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
Operation
Note
Caution