Carrier AQUASNAP AIR COOLED CHILLERS WITH COMFORTLINK CONTROLS 30RAP010-060 Operation And Service Manual

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Carrier AQUASNAP AIR COOLED CHILLERS WITH COMFORTLINK CONTROLS 30RAP010-060 Operation And Service Manual Manual pdf 64 page image

64• Check condenser coils for debris, clean as necessary.Every month:• Check moisture indicating sight glass for possible refrig-erant loss and presence of moisture.Every 3 months (for all machines):• Check refrigerant charge.• Check all refrigerant joints and valves for refrigerantleaks, repair as necessary.• Check chilled water flow switch operation.• Check all condenser fans for proper operation.• Check compressor oil level.Every 12 months (for all machines):• Check all electrical connections, tighten as necessary.• Inspect all contactors and relays, replace as necessary.• Check accuracy of thermistors, replace if greater than± 2° F (1.2° C) variance from calibrated thermometer.• Obtain and test an oil sample. Change oil only ifnecessary.• Check to be sure that the proper concentration of anti-freeze is present in the chilled water loop, if applicable.• Verify that the chilled water loop is properly treated.• Check refrigerant filter driers for excessive pressuredrop, replace as necessary.• Check chilled water strainers, clean as necessary.• Check cooler heater operation, if equipped.• Check condition of condenser fan blades and that theyare securely fastened to the motor shaft.• Perform Service Test to confirm operation of allcomponents.• Check for excessive cooler approach (Leaving ChilledWater Temperature — Saturated Suction Temperature)which may indicate fouling. Clean cooler vessel ifnecessary.Microchannel Heat Exchanger (MCHX) Con-denser Coil Maintenance and CleaningRecommendationsRoutine cleaning of coil surfaces is essential to maintainproper operation of the unit. Elimination of contamination andremoval of harmful residues will greatly increase the life of thecoil and extend the life of the unit. The following steps shouldbe taken to clean MCHX condenser coils:1. Remove any foreign objects or debris attached to thecoreface or trapped within the mounting frame andbrackets.2. Put on personal protective equipment including safetyglasses and/or face shield, waterproof clothing andgloves. It is recommended to use full coverage clothing.3. Start high pressure water sprayer and purge any soap orindustrial cleaners from sprayer before cleaning condens-er coils. Only clean, potable water is authorized for clean-ing condenser coils.4. Clean condenser face by spraying the core steady anduniformly from top to bottom while directing the spraystraight toward the core. Do not exceed 900 psig or 30 de-gree angle. The nozzle must be at least 12 in. from thecore face. Reduce pressure and use caution to preventdamage to air centers.TROUBLESHOOTINGComplete Unit Stoppage and Restart — Possi-ble causes for unit stoppage and reset methods are shown be-low and in Table 41. Refer to Fig. 3-7 for component arrange-ment and control wiring diagrams.GENERAL POWER FAILURE — After power is restored,restart is automatic through normal MBB start-up.UNIT ENABLE-OFF-REMOTE CONTACT SWITCH ISOFF — When the switch is OFF, the unit will stop immediate-ly. Place the switch in the ENABLE position for local switchcontrol or in the REMOTE CONTACT position for controlthrough remote contact closure.CHILLED FLUID PROOF-OF-FLOW SWITCH OPEN —After the problem causing the loss of flow has been corrected,reset is manual by resetting the alarm with the scrolling mar-quee as shown in Table 42.OPEN 24-V CONTROL CIRCUIT BREAKER(S) — De-termine the cause of the failure and correct. Reset circuit break-er(s). Restart is automatic after MBB start-up cycle iscomplete.COOLING LOAD SATISFIED — Unit shuts down whencooling load has been satisfied. Unit restarts when required tosatisfy leaving fluid temperature set point.THERMISTOR FAILURE — If a thermistor fails in either anopen or shorted condition, the unit will be shut down. ReplaceEWT, LWT, or OAT as required. Unit restarts automatically,but must be reset manually by resetting the alarm with thescrolling marquee as shown in Table 42.LOW SATURATED SUCTION — Several conditions canlead to low saturated suction alarms and the chiller controlshave several override modes built in which will attempt to keepthe chiller from shutting down. Low fluid flow, low refrigerantcharge and plugged filter driers are the main causes for thiscondition. To avoid permanent damage and potential freezingof the system, do NOT repeatedly reset these alert and/or alarmconditions without identifying and correcting the cause(s).COMPRESSOR SAFETIES — The 30RAP units with Com-fortLink™ controls include a compressor protection board thatprotects the operation of each of the compressors. Each boardsenses the presence or absence of current to each compressor.If there is a command for a compressor to run and there isno current, then one of the following safeties or conditionshave turned the compressor off:Compressor Overcurrent — All compressors have internalline breaks or a motor protection device located in the com-pressor electrical box.Compressor Short Circuit — There will not be current if thecompressor circuit breaker that provides short circuit protectionhas tripped.Compressor Motor Over Temperature — The internal line-break or over temperature switch has opened.CAUTIONDo not apply any chemical cleaners to MCHX condensercoils. These cleaners can accelerate corrosion and damagethe coil.CAUTIONExcessive water pressure will fracture the braze betweenair centers and refrigerant tubes.CAUTIONIf unit stoppage occurs more than once as a result of any ofthe safety devices listed, determine and correct causebefore attempting another restart.