Figure 6−9 Electronic Expansion Valve - Carrier 69NT40-561-201 Operation & Service Manual

Typically any aluminum oxide that becomes detached
from evaporator fan stators will be blown into the wet
evaporator 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. This document can be found at:
www.nucalgon.com/products/coil_cleaners_tripower.htm
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. Mix at a ratio of 5 parts water / 1 part 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:
a. Remove the upper evaporator access panel inside of
the unit.
b. Spray the surface with water before applying the
cleaning 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 solution
is 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 tightly
and dispose of properly.
6.16 ELECTRONIC EXPANSION VALVE
The electronic expansion valve (EEV) is an automatic
device which maintains required superheat of the refrig-
erant gas leaving the evaporator. The valve functions
are: (a) automatic response of refrigerant flow to match
the 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 and
Screen
a. Removing an EEV:
Always turn OFF the unit circuit breaker
(CB-1) and disconnect main power supply
before 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 the
brazed 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 remove
valve.
5. Clean the valve stem with mild cleaner, if necessary.
b. Installing an EEV
1. Reverse steps 1 through 4 above to install a new
valve. Install valve and screen with cone of screen
pointing into liquid line at inlet to the valve.
2. During installation, make sure the EEV coil is
snapped 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 valve
body. See Figure 6−9.
Coil
FLOW
DIRECTION
Figure 6−9 Electronic Expansion Valve
3. Replace filter drier.
4. Evacuate to 500 microns by placing vacuum pump
on liquid line and suction service valve.
5. Open liquid line service valve and check refrigerant
level.
6. Check superheat. (Refer to Section 2.2).
7. Check unit operation by running Pre−trip (Refer to
Section 3.7).
6−11
WARNING
Coil
Boot
Electronic
Expansion
Valve
T-364