MTS Water Quality Guide - Manual (Page 8)

Heat Exchanger Care and Water Quality Guide 8 Heat Exchanger Care
What ambient conditions are required?
Operating
temperatures
Water-cooled heat exchangers used in HPUs, operate at a minimum ambient
temperature of 4°C (40°F) and a maximum ambient temperature of 40°C
(104°F).
Air-cooled heat exchangers operate effectively up to an ambient temperatures of
37°C (98°F).
A nameplate specifying operating pressures and temperatures is attached to each
heat exchanger by the manufacturer. The MTS Hydraulic Power Supply Product
Manual provided with your test system contains specific information on the fluid
temperatures and cooling water requirements for your HPU.
The Air-Cooler to SilentFlo® HPU Integration Product Information manual
provides system integration requirements for
MTS Air-Coolers used with
MTS Series 505 SilentFlo™ Hydraulic Power Units.
Environment
Heat exchangers should not be located in a corrosive atmosphere, as rapid
deterioration of the brass casing, cooling element, fan and motor (hydraulic fluid-
to-air units only) may take place, resulting in a shortened operating life and
unnecessary replacement costs.
Water quality
Water chemistry for hydraulic fluid-to-water heat exchangers, is critical for a
successful heat exchange system. Generally speaking, municipal drinking water
that is pollution free, bacteriologically safe, and has a neutral pH is perfectly
acceptable for hydraulic fluid-to-water heat exchangers.
Cooling tower water and natural water sources, such as wells, rivers, or ponds,
must be free of pollutants and treated to reduce contaminants to the same levels
as municipal drinking water.
Softened or distilled water may not be suitable as a cooling liquid because
although most of the minerals have been removed there is a higher than desirable
level of carbon dioxide and oxygen present in the water. High levels of carbon
dioxide and oxygen will act to decrease the protective layer of minerals that form
on the surface of the tube, and increase the formation of copper oxide.
If the source of cooling water is a cooling tower, the presence of contaminants
that are corrosive to metals will vary over time. Contaminants must be controlled
to the levels listed in the following table. Ideally, the pH level should be
maintained in the 6.5–8.0 range for most applications. Chlorine should be used to
limit the growth of microbiological organisms that are generated by protein
decay. You must be careful not to use excessive amounts of chlorine. The
chloride concentration in the cooling water must be kept to less than 5 ppm.
The following table lists the acceptable levels of common compounds allowed in
the cooling water supply: