Carrier AQUAZONE 50KQE Series Installation, Operation And Maintenance Instructions

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Carrier AQUAZONE 50KQE Series Installation, Operation And Maintenance Instructions Manual pdf 23 page image

236.5 - Anti-freezeIn areas where entering loop temperatures drop below 4.4∞C orwhere piping will be routed through areas subject to freezing,anti-freeze is needed.Alcohols and glycols are commonly used as anti-freeze agents.Freeze protection should be maintained to 8.3 K below the lowestexpected entering loop temperature. For example, if the lowestexpected entering loop temperature is -1.1∞C, the leaving looptemperature would be -5.6 to -3.9∞C. Therefore, the freezeprotection should be at -9.4∞C (-1.1∞C -8.3∞C = -9.4∞C).IMPORTANT: All alcohols should be pre-mixed and pumpedfrom a reservoir outside of the building or introduced underwater level to prevent fuming.Calculate the total volume of fluid in the piping system (seeTable 9). Use the percentage by volume in Table 10 to determinethe amount of anti-freeze to use. Anti-freeze concentration shouldbe checked from a well mixed sample using a hydrometer tomeasure specific gravity.6.5.1 - Freeze protection selectionThe -1.1∞C FP1 factory setting (water) should be used to avoidfreeze damage to the unit.Once anti-freeze is selected, the JW3 jumper (FP1) should beclipped on the control to select the low temperature (anti-freeze-12.2∞C) set point to avoid nuisance faults.6.6 - Cooling tower/boiler systemsThese systems typically use a common loop maintained at 15.6to 32.2∞C. Carrier recommends using a closed circuit evaporativecooling tower with a secondary heat exchanger between thetower and the water loop. If an open type cooling tower is usedcontinuously, chemical treatment and filtering will be necessary.Table 9 - Approximate fluid volume (l) per 30 m ofpipePipe Diameter, in Volume, lCopper 1 15.51-1/4 24.21-1/2 34.8Rubber hose 1 14.8Polyethylene 3/4 IPS SDR11 10.61 IPS SDR11 17.01-1/4 IPS SDR11 30.61/2 IPS SDR11 41.32 IPS SDR11 68.11-1/4 IPS SCH40 31.41-1/2 IPS SCH40 41.32 IPS SCH40 64.4LegendIPS - Internal pipe sizeSCH - ScheduleSDR - Standard dimensional ratioNote: Volume of heat exchanger is approximately 3.78 litres.Table 10 - Anti-freeze percentages by volumeAnti-freeze Minimum temperature for freeze protection, ∞C-12.2 -9.4 -6.7 -3.9Methanol (%) 25 21 16 10100% USP food gradePropylene glycol (%) 38 30 22 156.7 - Ground coupled, closed loop and plateframeheat exchanger well systemsThese systems allow water temperatures from -1.1 to 43.3∞C.The external loop field is divided up into 51 mm polyethylenesupply and return lines. Each line has valves connected in sucha way that upon system start-up, each line can be isolated forflushing using only the system pumps. Locate air separation inthe piping system prior to the fluid re-entering the loop field.