Manual 2100-749
Page
17 of 68
Electronic Expansion Valve (EEV)
EEV Components
Electronic Expansion Valve
The electronic expansion valve is a stepper motor that
is controlled with a step output from the controller. The
valve is capable of 480 steps represented by a 0-100%
signal on the controller. The motor drives a needle valve
that regulates the flow of refrigerant.
EEV Instructions for Vacuum, Reclaim, Charge Unit
The electronic expansion valve moves to the 40% open
position when the unit is not actively cooling. The
valve may need to be manually positioned for service or
troubleshooting. The valve can be positioned by using a
menu override.
To manually override the valve:
1. Turn the unit off using the TEC-EYE. See
Unit On/
Off
on page 13 for instructions on how to turn unit
off using the TEC-EYE.
2. Press MENU key to go to the Main Menu screen.
3. Press UP or DOWN keys and ENTER key to enter
TECHNICIAN password 1313.
4. Press UP or DOWN keys to scroll to
I/O Config
;
press ENTER key.
5. Press UP or DOWN keys to scroll to
Manual EEV
;
press ENTER key.
6. Press UP or DOWN keys to scroll to
EEV Circuit 1
C6-1
or
EEV Circuit 2 C6-2.
7. Press ENTER key to scroll to
Service Pos
(see
Figure 22).
8. Press UP or DOWN keys to adjust to the desired
value.
9 Press ENTER key to scroll to
Enable.
10. Press UP or DOWN key to change
Off
to
On
.
11. Press ENTER key to save.
After the service or troubleshooting is completed,
use TEC-EYE to disable the EEV manual positioning
override and turn unit back on.
The valve can also be opened or closed using the EEV
service tool (Bard Part # 2151-021). This magnetic EEV
service tool (shown in Figure 23) is used to manually
open the EEV. To do this, remove the EEV stator coil (red
color with retaining nut on top), slide the magnetic tool
over the shaft where the stator was removed and turn in
a clockwise direction to open the valve to the full open
position (directional arrows are provided on the tool).
Opening the valve to the full open position will aid in the
refrigerant reclamation and evacuation processes.
With the stator removed, the resistance should be 40
ohms +/- 10%. There are two sets of three wires that
will have this resistance.
After removing the EEV service tool, reapply the EEV
stator coil and retaining nut. Upon powering the unit
back up, the control board will automatically drive the
EEV back to the fully shut position, and then back to
the 20% open position prior to starting the compressor
back up. Once the compressor starts, the control board
will again modulate the EEV position to control the
system superheat.
FIGURE 22
Overriding EEV Output
FIGURE 23
Electronic Expansion Valve (EEV) and Service Tool
EEV Service
Tool
EEV Stator
Coil
EEV
FIGURE 21
Adjusting Heating Differentials
