Carrier OMNIZONE 50BV020-064 Installation And Service Instructions Manual

Also see for OMNIZONE 50BV020: Operating and troubleshooting guide

Contents

49SERVICECompressor Rotation — To determine whether or notthe compressor is rotating in the proper direction:1. Connect service gages to suction and discharge pressurefittings.2. Energize the compressor.The suction pressure should drop and the discharge pres-sure should rise, as is normal on any start-up. If the suc-tion pressure does not drop and the discharge pressuredoes not rise to normal levels:3. Turn off power to the unit and tag disconnect.4. Reverse any 2 of the unit power leads.Reapply power to the unit. The suction and dischargepressure levels should now move to their normal start-uplevels.Also, check that the fan is rotating in the proper direction.NOTE: When the compressor is rotating in the wrong direc-tion, the unit makes an elevated level of noise and does notprovide cooling.Fan Motor Replacement — If required, replace thefan motor with an equal or better type and efficiency motorwith equal horsepower. The motor must be rated for a VFD orinverter application. Do not change the horsepower unlessthere is a system design requirement change and VFD sizeanalysis.CHECK/CHANGE VFD OUTPUT CURRENT LIMIT —The VFD provides additional fan motor protection by limitingthe output current to a programmed value. This value has beenfactory set according to the factory-installed motor and VFDsizing options.If the VFD and/or motor is replaced, the VFD setup modeparameter "tHr1" should be reprogrammed to the followingcalculated values for optimum motor protection and operatingrange:For VFD size about equal to motor:tHr1 = 100*motor nameplate Amps / VFD rated output AmpsMAINTENANCECleaning Unit Exterior — Unit exterior panels shouldbe wiped down using a damp soft cloth or sponge with a mix-ture of warm water and a mild detergent.Coil Cleaning — Hot water, steam, and direct expansioncoils must be cleaned at least once a year to maintain peak per-formance. Dirty coils can contribute to decreased heating orcooling capacity and efficiency, increased operating costs, andcompressor problems on direct expansion systems. Dirt,grease, and other oils can also reduce the wettability of the coilsurfaces, which can result in moisture blow-off from coolingcoils and resulting water leakage problems. If the grime on thesurface of the coils becomes wet, which commonly occurs withcooling coils, microbial growth (mold) can result, causing foulodors and health related indoor air quality problems.Coils can become dirty over a period of time, especiallyif air filter maintenance is neglected. Coils should be in-spected regularly and cleaned when necessary. Clean coilswith a vacuum cleaner, fresh water, compressed air, or abristle brush (not wire). Do not use high-pressure water orair. Damage to fins may result. Backflush coil to remove de-bris. Commercial coil cleaners may also be used to help re-move grease and dirt. Steam cleaning is NOT recommend-ed. After cleaning, use a fin comb of the correct fin spacingwhen straightening mashed or bent coil fins.Units installed in corrosive environments should becleaned as part of a planned maintenance schedule. In thistype of application, all accumulations of dirt should becleaned off the coil.Inspection — Check coil baffles for tight fit to prevent airfrom bypassing the coil. Check panels for air leakage, particu-larly those sealing the fan and coil compartments. Check forloose electrical connections, compressor oil levels, proper re-frigerant charge, and refrigerant piping leaks. Before start-up,be sure all optional service valves are open.Air Filters — The 50BV single-piece units come with 1-in.filters. The standard 1-in. filters provide lower pressure dropand longer filter service intervals. The 50BV modular unitscome with 4-in. filters.Inspect air filters every 30 days and replace filters asnecessary.Replacement filters should have a minimum efficiency rat-ing of MERV 6 per ASHRAE rating procedures and be ratedfor up to 625 fpm velocity. Job requirements or local codesmay specify higher minimum ratings.Condensate Drains — Clean the drain line and unitdrain pan at the start of each cooling season. Check flow bypouring water into the drain.Water-Cooled Condensers — Water-cooled condens-ers may require cleaning of the scale (water deposits) due toimproperly maintained closed-loop water systems. Sludgebuild-up may need to be cleaned in an open tower system dueto inducted contaminants.Local water conditions may cause excessive fouling or pit-ting of tubes. Condenser tubes should be cleaned at least once ayear, or more often if the water is contaminated.Proper water treatment can minimize tube fouling andpitting. If such conditions are anticipated, water treatmentanalysis is recommended. Refer to the System Design Manual,Part 5, for general water conditioning information.Isolate the supply and return water connections when re-moving piping to the condenser.Clean condensers with an inhibited hydrochloric acid solu-tion. The acid can stain hands and clothing, attack concrete,and, without inhibitor, can attack steel. Cover surroundings toguard against splashing. Vapors from vent pipe are not harmful,but take care to prevent liquid from being carried over by thegases.Warm solution acts faster, but cold solution is just as effec-tive if applied for a longer period.CAUTIONImproper phase sequence will cause scroll compressorfailure due to reverse rotation.Signs of miswire are:• Excessive noise• Reverse rotation of 3 phase indoor fan• Rapid temperature rise on suction tube• No pressure differentialCorrect immediately. Shut off power at disconnectand switch any 2 power leads at unit terminal block orpigtails.CAUTIONFollow all safety codes. Wear safety glasses and rubbergloves when using inhibited hydrochloric acid solution.Observe and follow acid manufacturer’s instructions.