Carrier 17/19EX - Manual (Page 247)

Condenser
Since this water circuit is usually an open-type system, the tubes may be subject to
contamination and scale. Clean the condenser tubes with a rotary tube cleaning system at least
once per year, and more often if the water is contaminated. Inspect the entering and leaving
condenser water sensors for signs of slime, corrosion, or scale. Replace the sensor if corroded
or remove any scale if found.
Higher than normal condenser pressures, together with the inability to reach full refrigeration
load, usually indicate dirty tubes or air in the machine. If the refrigeration log indicates a rise
above normal condenser pressures, check the condenser refrigerant temperature against the
leaving condenser water temperature. If this reading is more than what the design difference is
supposed to be, then the condenser tubes may be dirty, or water flow may be incorrect.
Because HFC134-a is a high-pressure refrigerant, air usually does not enter the machine,
rather, the refrigerant leaks out.
During the tube cleaning process, use brushes especially designed to avoid scraping and
scratching the tube wall. Contact your Carrier representative to obtain these brushes. Do not
use wire brushes.