Filters; Cleaning Cshe; Storage; Exchanger Maintenance - Hertz HDD Series Instruction Manual

OPTIONAL COOLING SYSTEM

4.1.2 Filters

If there are particles larger than 1 mm (0.04 inches) in the environment, we recommend a filter with a pore
size of 16-20 (number of holes per inch) to be installed upstream the exchanger. Otherwise the particles
may block the channels and cause poor performance, pressure drops or freezing.

4.1.3 Cleaning CSHE

CSHE's create a self-cleaning effect due to the high turbulence inside. However, the exchanger may tend to
fail at high temperatures and where very hard water is used. In such cases, it is possible to clean the
exchanger with circulation of cleaning fluid. Use a tank containing a solution of 5% phosphoric acid or 5%
oxalic acid if the exchanger is cleaned frequently. Pump the cleaning fluid into the exchanger. For optimum
cleaning, the flow rate of the cleaning solution should be at least 1,5 times the usual flow rate preferably at
backwash mode. Remember to wash the heat exchanger thoroughly with clean water after use. Using a 1-
2% sodium hydroxide (NaOH) solution or a sodium bicarbonate (NaHCO3) solution before the final rinse
guarantees neutralization of the acid. Clean at regular intervals Contact HERTZ technical service
department for more information on cleaning CSHE's.

4.1.4 Storage

CSHE's should be stored dry. The temperature should be between 63°F (17°C) and 122°F (50°C).

4.1.5 Exchanger Maintenance:

•
Exchanger should always be installed vertically.
•
The fluid inlets on the exchanger should have opposite directions.
•
In order to avoid pollution of the exchanger, filters that would stop particles larger than 1 mm should
be installed on the cold water inlet of the compressor.
•
In case the cooling performance of the exchanger drops, it should be cleaned by circulation of
inflammable cleaning materials (detergent or weak acid) in the opposite direction of the normal flow.
The exchanger can be removed for this operation if necessary. The exchanger must be rinsed with
water after cleaning.
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