Carrier 30RB060-390 Installation Instructions Manual

Also see for MINIMUM LOAD CONTROL ACCESSORY 30RB060-390: Installation instructions

52Normally, a closed system needs to be filled only once. Theactual filling process is a fairly simple procedure. All air shouldbe purged or vented from the system. Thorough venting at highpoints and circulation at room temperature for several hours ishighly recommended.NOTE: Local codes concerning backflow devices and otherprotection of the city water system should be consulted andfollowed to prevent contamination of the public water supply.This is critical when antifreeze is used in the system.SET WATER FLOW RATE — Once the system is cleaned,pressurized, and filled, the flow rate through the chiller andheat reclaim needs to be established. Refer to the Job Sub-mittal for flow rate requirements. See the Controls andTroubleshooting literature for operating limits. On unitswith the hydronic package, this can be accomplished byusing the balancing valve. Follow the manufacturer’s rec-ommendations for setting the balancing valve. Local codesmay prohibit restricting the amount of water using the bal-ancing valve for a given motor horsepower. In this case, usethe method listed in the Pump Modification/Trimming sec-tion. See Table 7 for the type of combination valve in 30RBunits with the optional hydronic package.Table 7 — Combination Valve DetailsNOTE: Carrier recommends a differential pressure gage whenmeasuring pressures across the pumps or balancing valves.This provides for greater accuracy and reduces error build-upthat often occurs when subtracting pressures made by differentgages.A rough estimate of water flow can also be obtained fromthe pressure gages across the 30RB heat exchangers.Figures 52-56 show the relationship between gpm and heatexchanger pressure drop. It should be noted that these curvesare for fresh water and “clean” heat exchangers; they do notapply to heat exchangers with fouling. To read the chart,subtract the readings of the two pressure gages on the hydronickit. This number is the pressure drop across the heat exchanger.Adjust the factory-installed balancing valve or external balanc-ing valve (in units without hydronic package) until the correctpressure drop is obtained for the required gpm.PUMP MODIFICATION/TRIMMING — Since the pumpsare constant speed, the only way to obtain greater flow with agiven pump/impeller is to decrease system head. This willallow the pump to “ride” its curve to the right, resulting inincreased flow. If greater flow is necessary, consider openingthe combination valve. Also, verify that the strainer is clean,and that no unnecessary system resistance is present, such aspartially closed isolation valves.Once the combination valve is set, note the stem position. Iflater service work requires the valve to be closed, it will be easierto re-balance the system, if the original balance point is known.Increasing system resistance by closing the balancing valvewill force the pump to “ride” its curve to the left, resulting inless flow. Although this does reduce power consumptionslightly, it may not be the desirable method of reducing theflow, especially if a large reduction is needed.0(0.00)200(12.62)400(25.24)600(37.85)800(50.47)(gpm)(l/s)us(42.7) 140Head Pressure(m) ft of fluidFlow Rate(36.6) 120(30.5) 100(24.4) 80(18.3) 60(12.2) 40(6.1) 20(0.0) 01000(63.09)3450 RPMNPSHrNPSHra30-5471LEGENDNPSHr — Net Positive Suction Head (Pressure) RequiredNOTE: Refer to the 30RB nomenclature, Fig. 1, for option identification. Refer to the Pump Impeller Sizes, Table 6, for more information.Fig. 51 — Pump Curve VIIIB for Hydronic Package Dual Pump (Fresh Water)30RB UNIT SINGLE/DUAL PUMP060-130 FTV-4 in.150-190 FTV-6 in.