Carrier 30GTN Service And Troubleshooting Manual

Also see for 30GTN: Product data Installation instructions Installation instructions

Carrier 30GTN Service And Troubleshooting Manual Manual pdf 65 page image

START-UP AND OPERATIONNOTE: Refer to Start-Up Checklist on pages CL-1 to CL-8.Actual Start-Up — Actual start-up should be doneonly under supervision of a qualified refrigerationmechanic.1. Be sure all service valves are open. Units are shipped fromfactory with suction, discharge, and liquid line serv-ice valves closed.2. Using the Marquee display, set leaving-fluid set point (CSP.1is Set Point mode under sub-mode COOL). No coolingrange adjustment is necessary.3. If optional control functions or accessories are being used,the unit must be properly configured. Refer to OperatingData section for details.4. Start chilled fluid pump.5. Turn ENABLE/OFF/REMOTE CONTACT switch to EN-ABLE position.6. Allow unit to operate and confirm that everything is func-tioning properly. Check to see that leaving fluid tempera-ture agrees with leaving set point (CSP.1 or CSP.2), or ifreset is used, with the control point (CTPT) in the RunStatus mode under the sub-mode VIEW.Operating LimitationsTEMPERATURES (See Table 33) — If unit is to be used inan area with high solar radiation, mounted position shouldbe such that control box is not exposed to direct solarradiation. Exposure to direct solar radiation could affect thetemperature switch controlling cooler heaters.Table 33 — Temperature Limits for Standard UnitsTEMPERATURE F CMaximum Ambient Temperature 125 52Minimum Ambient Temperature 0 −18Maximum Cooler EWT* 95 35Maximum Cooler LWT 70 21Minimum Cooler LWT† 38 3.3LEGENDEWT — Entering Fluid (Water) TemperatureLWT — Leaving Fluid (Water) Temperature*For sustained operation, EWT should not exceed 85 F (29.4 C).†Unit requires modification below this temperature.Low-Ambient Operation — If operating temperatures be-low 0° F (−18 C) are expected, refer to separate installationinstructions for low-ambient operation using accessory Motor-mastert III control. Contact your Carrier representative fordetails.NOTE: Wind baffles and brackets must be field-fabricatedfor all units using accessory Motormaster III controls to en-sure proper cooling cycle operation at low-ambient tempera-tures. See Installation Instructions shipped with the Motor-master III accessory for more details.Brine duty application (below 38 F [3.3 C] LCWT)for chiller normally requires factory modification.Contact your Carrier representative for applicable LCWTrange for standard water-cooled chiller in a specificapplication.VOLTAGEMain Power Supply — Minimum and maximum acceptablesupply voltages are listed in the Installation Instructions.Unbalanced 3-Phase Supply Voltage — Never operate a mo-tor where a phase imbalance between phases is greater than2%. To determine percent voltage imbalance:max voltage deviationfrom avg voltage% Voltage Imbalance = 100 x average voltageThe maximum voltage deviation is the largest differencebetween a voltage measurement across 2 legs and the aver-age across all 3 legs.Example: Supply voltage is 240-3-60.AB = 243 vBC = 236 vAC = 238 v1. Determine average voltage:243 + 236 + 238Average voltage = 3717= 3= 239 v2. Determine maximum deviation from average voltage:(AB) 243 − 239 = 4 v(BC) 239 − 236 = 3 v(AC) 239 − 238 = 1 vMaximum deviation is 4 v.3. Determine percent voltage imbalance:4% Voltage Imbalance = 100 x 239= 1.7%This voltage imbalance is satisfactory as it is below themaximum allowable of 2%.IMPORTANT: If the supply voltage phase imbalanceis more than 2%, contact your local electric utility com-pany immediately. Do not operate unit until imbalancecondition is corrected.Control Circuit Power — Electronic control includes logicto detect low control circuit voltage. Acceptable voltage rangesare shown in the Installation Instructions.MINIMUM FLUID LOOP VOLUME — To obtain propertemperature control, loop fluid volume must be at least3 gallons per ton (3.25 L per kW) of chiller nominal capac-ity for air conditioning and at least 6 gallons per ton (6.5 Lper kW) for process applications or systems that must op-erate at low ambient temperatures (below 32 F [0° C]).Refer to application information in Product Data literaturefor details.FLOW RATE REQUIREMENTS — Standard chillers shouldbe applied with nominal flow rates approximating those listedin Table 34. Higher or lower flow rates are permissible toobtain lower or higher temperature rises. Minimum flow ratesmust be exceeded to assure turbulent flow and proper heattransfer in the cooler.Operation below minimum flow rate could subject tubesto frost pinching in tube sheet, resulting in failure ofcooler.65