SPX Cooling Technologies Marley MCW Humidifier User Manual


 
Marley
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MCW Cooling Tower
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Engineering Data: Freeze Prevention
20
When the ambient air temperature falls below 0°C, the
water in a cooling tower can freeze. Marley Technical Report
#H-003 “Operating Cooling Towers in Freezing Weather”
describes how to prevent freezing during operation. Available
at spxcooling.com or ask your Marley sales representative for a
copy.
During shutdown, water collects in the cold water basin and
may freeze solid. You can prevent freezing by adding heat to
the water left in the tower—or, you can drain the tower and all
exposed pipework at shutdown.
Electric Basin Heaters
An automatic basin water heater system is available
consisting of the following components:
• Stainlesssteelelectricimmersionheater(s).
—Threaded couplings are provided in the side of the
collection basin.
• IP56enclosurecontaining:
—Magnetic contactor to energize heater.
—Transformer to convert power supply to 24 volts for
control circuit.
—Solid state circuit board for temperature and
low-water cutoff.
Enclosure may be mounted on the side of the tower.
• Controlprobeinthecollectionbasintomonitorwater
temperature and level.
Heater components are normally shipped separately for
installation by others.
Note: any exposed piping that is still filled with water
at shutdown—including the makeup water line—should be
electricallytracedandinsulated(byothers).
Indoor Storage Tank
With this type of system, water flows from an indoor tank,
through the load system, and back to the tower, where it is
cooled. The cooled water flows by gravity from the tower to the
tank located in a heated space. At shutdown, all exposed water
drains into the tank, where it is safe from freezing.
The amount of water needed to successfully operate the
system depends on the tower size and L/s and on the volume
of water contained in the piping system to and from the tower.
You must select a tank large enough to contain those combined
volumes—plus a level sufficient to maintain a flooded suction
on your pump. Control makeup water according to the level
where the tank stabilizes during operation.