Pfannenberg PWS Series - Manual (Page 11)

8
SECTION 9: DESIGN DATA
Please refer to the cooling unit individual
technical data sheets for the following:
Dimensional Data
Mounting Cutout
Circuit Diagrams
9.1 Water Quality Notes
The following guidelines must be complied with to ensure safe and reliable operation of air/water heat
exchangers.
Cooling water should not contain any sedimentation, should be of low hardness (low carbon hardness in
particular), especially for re-cooling. However, it should not be so soft that it corrodes material/s used in the
exchanger.
When recycling cooling water the saline content due to evaporation of larger quantities of water must not be too
high (increasing concentrations of dissolved substances increase electrical conductivity, resulting in the water
becoming more corrosive).
Constantly remove some enriched water and replace it with an equal amount of fresh water.
Water containing gypsum is unsuitable for cooling, as it tends to cause scale deposits, which are very hard to
remove.
Cooling water should be iron- and manganese-free (deposits leading to piping blockage may otherwise result).
Organic substances (sludge and microbiological contaminants)should only be present in the water in very small
amounts.
Common contamination forms and remedies
Water Contamination Remedy
Mechanical contamination
Filter water using -Sieve filters
- Gravel filters
- Cartridge filters -Pre-coated filters
Excessive hardness Soften water using ion exchange
Moderate mechanical contaminant and hardness
promoting substance content
Treat water using stabilisers or dispersants
Moderate chemical contaminant content Treat water using passivation media and / or inhibitors
Biological contamination - sludge bacteria, algae Treat water with biocides