Technical data

Table Of Contents
FAULTS
6 720 803 687 (2012/11) 75
CONTROL SIGNAL SWITCHING PATTERN
The switching pattern of the control signals changes as follows, if the
valve:
• should open: 1 2 3 4 5 6 7 8 1
should close: 8 7 6 5 4 3 2 1 8
All outputs 1 to 4 will be switched off if the current valve position is to
be maintained.
In the case of an error in the output signals, for example if an output is
missing or signals are sent permanently, the valve drive cannot open or
close evenly. Movement will be jerky and vibrations can be heard and
felt.
FUNCTION AND OPERATION
On switching the power supply on, an opening signal of 700 pulses will
be sent to ensure that the valve is in position [5]. The signal remains
active for approximately 20 seconds. The LEV normally operates free of
noise and vibrations. Increased noise can be heard from the valve if it is
blocked or is being moved from [6] to [5].
No noise can be heard if the drive is faulty or has a wiring fault.
Fig. 66 LEV function diagram
[x] Complete closing (200 pulses)
[1] Level of opening of the LEV (top open, bottom closed)
[2] LEV pulses (fully open at 500 pulses)
[3] Valve closes
[4] Valve opens
[5] Position 1
[6] Position 2
The extent to which the linear expansion valve opens
depends on the number of pulses that are supplied by
the PCB drive circuit to the LEV drive.
Output (phase)
Signal pattern
1 2 3 4 5 6 7 8
1 ONONOFFOFFOFFOFFOFFON
2 OFF ON ON ON OFF OFF OFF OFF
3 OFF OFF OFF ON ON ON OFF OFF
4 OFF OFF OFF OFF OFF ON ON ON
Table 46 Control signal switching pattern
To ascertain whether the valve is making any noise, hold
the tip of a screwdriver against the valve body and listen
with your ear against the screwdriver handle.
1
5
6
2
x
3
4
6 720 646 970-117.1ITL