Bard 11EER WA W18AB-A, Руководство пользователя для приложения

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Manual 7960-811
Page
2 of 13
Electronic Expansion Valve
Operation
This model employs an electronic expansion valve
(EEV) which meters the refrigerant to the evaporator.
The EEV is made of a stepper motor that is controlled
with a step output from the controller. The valve is
capable of 480 steps which drives a needle valve that
in turn regulates the flow of refrigerant. The EEV allows
for tighter control and better capacity management in
varying operating conditions than a standard TXV. The
EEV system consists of the electronic valve and stator,
control board, suction temperature sensor and suction
pressure transducer. The pressure transducer and
temperature sensor monitor the suction line to provide
real time data to the control board so that a real time
superheat can be calculated. This then determines the
EEV position. The controller is sent to maintain around
13° superheat.
EEV Instructions for Vacuuming, Reclaiming and
Charging Unit
The electronic expansion valve moves to a closed
position when there is no call to control. In order to
pull a complete vacuum, fully reclaim the system or
charge the unit, connections to both the suction and
discharge service ports need to be utilized or the valve
needs to be manually opened first. The valve can be
opened manually using the magnetic EEV service tool
(Bard Part # 2151-021) shown in Figure 1. 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).
Reapply the EEV stator coil and retaining nut once
complete. Upon powering the unit back up, the control
board will automatically drive the EEV back to the fully
shut position. Once the compressor starts, the control
board will again modulate the EEV position to control
the system superheat.
EEV Troubleshooting
The control board has two status LEDs.
• The green LED should be lit anytime that the board
has power and the control is functioning.
• The red LED is to show that an alarm is present.
See Table 1 for EEV troubleshooting. Refer to the
appropriate unit replacement parts manual for any parts
that are needed.
FIGURE 1
Electronic Expansion Valve (EEV) and Service Tool
EEV Service
Tool
EEV Stator
Coil
EEV