T-340
7–18
aluminum parts within the container. If left untreated over time, it may build up in thickness and eventually flake as a
light-weight white powder.
The surface corrosion of aluminum is brought about by exposure to chemicals such as sulfur dioxide and possibly
other fumigants that are commonly used for fumigation and protection of some perishable cargo such as grapes,
for example. Fumigation is the process by which a chemical is released into an enclosed area to eliminate infesta
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tions of insects, termites, rodents, weeds and soil-born disease.
Typically any aluminum oxide that becomes detached from evaporator fan stators will be blown into the wet evapo
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rator coil where it will be caught and then flushed out of the unit during routine defrost cycles.
However, it is still highly recommended that after carrying cargo subject to fumigation procedures, that the inside of
the unit be thoroughly cleansed prior to reuse.
Carrier Transicold has identified a fully biodegradable and environmentally safe alkaline cleaning agent (Tri-
Pow’r® HD) for the unit. This will assist in helping to remove the corrosive fumigation chemicals and dislodging of
the corrosive elements.
This cleaner is available from the Carrier Transicold Performance Parts Group (PPG) and can be ordered through any
of the PPG locations; Part Number NU4371-88.
As a general safety precaution, before using this product, refer to and retain the Material Safety Data (MSDS) sheet.
Prior to Cleaning:
• Always wear goggles, gloves and work boots.
• Avoid contact with skin and clothing, and avoid breathing mists.
• When mixing, add water to the sprayer first, then the cleaner.
• ALWAYS provide for proper ventilation when cleaning indoor evaporator coils (rear doors must be open).
• Be aware of surroundings - food, plants, etc., and the potential for human exposure.
• Always read directions and follow recommended dilution ratios. More is not always better. Using non-diluted
cleaner is not recommended.
Cleaning Procedure:
1. Remove the upper evaporator access panel inside of the unit.
2. Spray the surface with water before applying the cleaning solution. This helps the cleaner work better.
3. Liberally apply the prepared cleaner solution (5 parts water and 1 part cleaner).
4. Allow the cleaner to soak in for 5 to 7 minutes.
5. Assess area for rinsing. Follow all local regulations regarding disposal of waste water.
6. Thoroughly rinse the cleaner and surrounding area, floor, etc.When rinsing where heavy foaming solution is
present, it is very important to take the time to thoroughly rinse the equipment and surroundings.
7. Always rinse the empty coil cleaner bottle, cap tightly and dispose of properly.
7.17 Electronic Expansion Valve (EEV)
The electronic expansion valve (EEV) is an automatic device which maintains required superheat of the refrigerant
gas leaving the evaporator. The valve functions are: (a) automatic response of refrigerant flow to match the evapo
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rator load and (b) prevention of liquid refrigerant entering the compressor. Unless the valve is defective, it seldom
requires any maintenance
7.17.1
Removing an EEV
1. Pump down the compressor (see
) and frontseat both suction and discharge valves.
2. Turn unit power off and remove power from the unit.
3. Remove coil.
4. Remove the valve. The preferred method of removing the valve is to cut the connection between the brazed
section and the valve, using a small tube cutter. Remove the valve.
Alternately, use a wet rag to keep valve cool. Heat inlet and outlet connections to valve body and
remove valve.
5. Clean the valve stem with mild cleaner, if necessary.
