Carrier 69NT40-561-201 Operation & Service Manual

6−11 T-364Typically any aluminum oxide that becomes detachedfrom evaporator fan stators will be blown into the wetevaporator coil where it will be caught and then flushedout of the unit during routine defrost cycles.However, it is still highly recommended that aftercarrying cargo subject to fumigation procedures, thatthe inside of the unit be thoroughly cleansed prior toreuse.Carrier Transicold has identified a fully biodegradableand environmentally safe alkaline cleaning agent(Tri−Pow’r® HD) for the unit. This will assist in helping toremove the corrosive fumigation chemicals anddislodging of the corrosive elements.This cleaner is available from the Carrier TransicoldPerformance Parts Group (PPG) and can be orderedthrough any of the PPG locations; Part NumberNU4371−88.As a general safety precaution, before using thisproduct, refer to and retain the Material Safety Data(MSDS) sheet. This document can be found at:www.nucalgon.com/products/coil_cleaners_tripower.htmPrior to Cleaning:− Always wear goggles, gloves and work boots.− Avoid contact with skin and clothing, and avoidbreathing mists.− When mixing, add water to the sprayer first, then thecleaner. Mix at a ratio of 5 parts water / 1 part cleaner.− ALWAYS provide for proper ventilation when cleaningindoor evaporator coils (rear doors must be open).− Be aware of surroundings − food, plants, etc., and thepotential for human exposure.− Always read directions and follow recommendeddilution ratios. More is not always better. Usingnon−diluted cleaner is not recommended.Cleaning Procedure:a. Remove the upper evaporator access panel inside ofthe unit.b. Spray the surface with water before applying thecleaning solution. This helps the cleaner work better.c. Liberally apply the prepared cleaner solution.d. Allow the cleaner to soak in for 5 to 7 minutes.e. Assess area for rinsing. Follow all local regulations re-garding disposal of waste water.f. Thoroughly rinse the cleaner and surrounding area,floor, etc. When rinsing where heavy foaming solutionis present, it is very important to take the time to thor-oughly rinse the equipment and surroundings.g. Always rinse the empty coil cleaner bottle, cap tightlyand dispose of properly.6.16 ELECTRONIC EXPANSION VALVEThe electronic expansion valve (EEV) is an automaticdevice which maintains required superheat of the refrig-erant gas leaving the evaporator. The valve functionsare: (a) automatic response of refrigerant flow to matchthe evaporator load and (b) prevention of liquid refriger-ant entering the compressor. Unless the valve is defec-tive, it seldom requires any maintenance.6.16.1 Replacing Electronic Expansion Valve andScreena. Removing an EEV:WARNINGAlways turn OFF the unit circuit breaker(CB-1) and disconnect main power supplybefore working on moving parts.1. Pump down the compressor (refer to paragraph 6.4)and frontseat both suction and discharge valves.2. Turn unit power off and remove power from the unit.3. Remove EEV coil.4. VALVE REMOVAL: The preferred method of remov-ing the valve is to cut the connection between thebrazed section and the valve, using a small tube cut-ter. Remove valve.Alternately, use a wet rag to keep valve cool. Heat in-let and outlet connections to valve body and removevalve.5. Clean the valve stem with mild cleaner, if necessary.b. Installing an EEV1. Reverse steps 1 through 4 above to install a newvalve. Install valve and screen with cone of screenpointing into liquid line at inlet to the valve.2. During installation, make sure the EEV coil issnapped down fully, and the coil retention tab is prop-erly seated in one of the valve body dimples. Also,ensure that coil boot is properly fitted over valvebody. See Figure 6−9.FLOWDIRECTIONCoilBootCoilElectronicExpansionValveFigure 6−9 Electronic Expansion Valve3. Replace filter drier.4. Evacuate to 500 microns by placing vacuum pumpon liquid line and suction service valve.5. Open liquid line service valve and check refrigerantlevel.6. Check superheat. (Refer to Section 2.2).7. Check unit operation by running Pre−trip (Refer toSection 3.7).