SPX Cooling Technologies Cooling Tower Marley MD, Engineering Data, Page: 26 / 40

Marley
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MD Cooling Tower / Engineering Data: Freeze Prevention
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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:
• Standard weatherproof (IP55) enclosure, rating
depending on model and minimum expected winter
temperature.
• Ratings are in kW for specified ambient temperature.
For lower ambient temperatures refer to SPX
engineering for advice.
• Standard electircal supply is 380/415 V 3ph (220/240V 1
ph available as extra cost option).
• Heater has an integral thermostat, set point nominally
3°C but adjustable to suit operating requirements.
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 GPM 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.