Danfoss VZH052 Manual page 41

Reduce moisture in the system
Requirements
Solutions
Excessive air and moisture
• can increase condensing pressure and cause
excessively high discharge temperatures.
• can create acid giving rise to copper platting.
• can destroy the lubricating properties of the oil.
VZH compressors are delivered with < 100 ppm
moisture level.
At the time of commissioning, system moisture
content may be up to 100 ppm.
To achieve this requirement, a properly sized
and type of drier is required. Important selection
criteria's include:
• driers water content capacity,
• system refrigeration capacity,
• system refrigerant charge.
All these phenomena can reduce service life
and cause mechanical and electrical compressor
failure.
During operation, the filter drier must reduce this
to a level between 20 and 50 ppm.
For new installations with VZH compressors with
PVE oil, Danfoss recommends using the Danfoss
DML (100% molecular sieve) solid core filter drier.
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