Electronic Expansion Valve (Eev); Eev Components; Electronic Expansion Valve; Low Pressure Transducer - Bard FUSION-TEC HR58APA Installation Support Materials

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.

Low Pressure Transducer

The unit has a low side pressure transducer installed
on the suction line between the evaporator coil
and compressor. The transducer is used for system
monitoring of low side system pressures. The sensor
is used with the suction temperature sensor to provide
a real time superheat calculation that determines the
EEV position.
This sensor can be verified and adjusted by:
1. Press MENU key to go to the Main Menu screen.
2. Press UP or DOWN keys and ENTER key to enter
USER password 2000.
3. Press UP or DOWN keys to scroll to I/O Config;
press ENTER key.
4. Press UP or DOWN keys to scroll to Suction Pr
Sensor (C11); press ENTER key.
5. Verify the measurement displayed on screen is
accurate (see Figure 2.11).
6. If the measurement needs to be adjusted, apply
an offset value by pressing ENTER to to scroll to
Offset.
7. Press UP or DOWN keys to adjust the offset.
8. The update will not take effect until the cursor is
moved out of the Offset parameter.
9. Once adjusted, press the ESCAPE key several
times to return to Main Menu screen.
FIGURE 2.11
Adjusting Low Pressure Sensor Values
Suction Temperature Sensor
The suction temperature sensor is used to calculate
superheat. The EEV uses this value to control the EEV.
The temperature is measured with a 10k ohm NTC
thermistor.
The suction temperature sensor measurement can be
verified and adjusted by:
1. Press MENU key to go to the Main Menu screen.
2. Press UP or DOWN keys and ENTER key to enter
USER password 2000.
3. Press UP or DOWN keys to scroll to I/O Config;
press ENTER key.
4. Press UP or DOWN keys to scroll to Suct Temp
Sensor (C9); press ENTER key.
5. Verify the measurement displayed on screen is
accurate (see Figure 2.12).
6. If the measurement needs to be adjusted, apply
an offset value by pressing ENTER to to scroll to
Offset.
7. Press UP or DOWN keys to adjust the offset.
8. The update will not take effect until the cursor is
moved out of the Offset parameter.
9. Once adjusted, press the ESCAPE key several
times to return to Main Menu screen.
FIGURE 2.12
Adjusting Suction Temperature Sensor Values

EEV Operation

EEV Superheat Control

The electronic expansion valve (EEV) will open or close
to maintain 10° of superheat while the compressor is
running. When the compressor is not running, the valve
will close.
Low superheat protection will be active once the
superheat value is at or below 5°F. At this point,
the control will aggressively close the valve so that
superheat is maintained.

EEV Instructions for Vacuum, Reclaim, Charge Unit

The electronic expansion moves to the 0 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.
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