phase (Test 2), the control unit inhibits burner startup and goes to lockout.
In that case, the lockout reset button lights up to indicate the fault.
Remote indication of the fault is also possible.
A program indicator, which stops whenever a fault occurs, indicates which
of the two valves is leaking.
Mode of operation
To carry out the first phase of the valve proving test, called "Test 1", there
must be atmospheric pressure in the length of pipe between the two val-
ves to be tested. In plants with a vent to the atmosphere, this pressure is
available if the valve proving test isconducted prior to or during the pre-
purge time. In plants without a vent pipe, atmospheric pressure is made
available as the control unit opens the valve on the burner side during the
time "t4". If the valve proving test is performed after the operation of the
burner, the valve on the burner side after the controlled shutdown can be
kept open until "t4" has elapsed, thus reducing the pressure in the test
space and making certain its gas content is burnt off in the combustion
chamber during the post-purge time. A prerequisite for this procedure is
an appropriate control program of the burner control as provided by Lan-
dis & Staefa burner controls type LFE..., LFL..., LGK.... or LEC.... The test
space is closed off after it has been evacuated.
During the first test phase (Test 1) which follows immediately, the control
unit checks if the atmospheric pressure in the test space is maintained
using the pressure monitor. If the valve on the mains side is leaking, cau-
sing the pressure to rise above the switching point of the pressure moni-
tor, the control unit initiates an alarm and goes to lockout.
The program indicator then stops and indicates "Test 1".
If the pressure does not increase because the valve closes correctly, the
control unit immediately programs the second test phase (Test 2). To do
this, the valve on the mains side is pressurized ("filling" of test space).
During the second test phase, the pressure may not fall below the
switching point of the pressure monitor due to a leak of the valve on the
burner side.
If it does, the control unit goes to lockout again, thus inhibiting burner star-
tup.
On the successful completion of the second test phase, the control unit
closes the internal control loop between terminals 3 and 6 (circuit path:
terminal 3 - contact "ar 2" -terminals 4 and 5 - contact III - terminal 6). This
control loop is usually included in the start control loop of the burner con-
trol.
After the control loop has been closed, the programming mechanism of
the control unit returns to its start position where it switches itself off.
During these "idle steps", the position of the control contacts of the pro-
gramming mechanism remains unchanged.
Program and lockout indicator
When the unit goes to lockout, the programming mechanism stops and
also the position indicator fitted to the spindle of the mechanism. The
symbol that stops above the reading mark not only indicates during which
test phase lockout occurred, but also after how many programming steps
within the test phase (1 step = 2.5 seconds).
Specifications
Mains voltage
AC 220 V -15 %...240 V +10 % AC 100 V
-15 %...110 V +10 % Mains frequency 50
Hz -6 %...60 Hz +6 %
Power consumption
- during the test
3.5 VA
- during burner operation
2.5 VA
Prefuse (externally)
T16/500 V
Unit fuse
T6,3H250 V to IEC 127
Radio interference protection
N to VDE 0875
Perm. input current at terminal 15 A continuous to VDE 0660 AC3
Environmental conditions:
Temperature
-50...+60 °C
Humidity
< 95 % r.h.
Mechanical conditions
class 2M2
Climatic conditions
class 3K5
Temperature
-20...+60 °C
Humidity
< 95 % r.h.
Condensation, formation of ice and influence of water are not permitted
Perm. current rating of control terminals4 A to VDE 0660 AC3
Required switching capacity of pressure switch "DW"1 A min.,
AC 250 V
Mounting position
optional
Degree of protection
IP40
Weight
control unit approx.
1000 g
base approx.
165 g
CE conformity
According to the directives of the Euro-
pean Community
Electromagnetic compatibility
EMC 89/336
EWG include. 92/31 EEC, Gas appliance directive 90/396 EEC
Emissions
EN 50081-1
Immunity
EN 50082-2
Start position = operating position
In plants without a vent valve: evacuation of test space
through opening of the valve on the burner side
Test 1
"Test 1" with atmospheric pressure (valve proving test on
the mains side)
Filling the test space through opening of the valve on the
mains side
Test 2
"Test 2" with gas pressure (valve proving test on the burner
side)
Idle steps until programming mechanism switches itself off
Operating position = start position for the next valve proving
test
In the event of lockout, all terminals receiving voltage from the control unit
are de-energized, except terminal 13, which is used for lockout indication.
After the unit has been reset, the programming mechanism automatically
returns to its
start position and immediately reprograms a new valve proving test.
Note: do not press the reset button for more than 10 seconds.
Control program after a power failure
A power failure prior to evacuating the test space does not cause the pro-
gram sequence to change.
If a power failure occurs after the evacuation, the valve proving test will
not be continued when power is restored, but the programming mecha-
nism first returns to its start position to reprogram the complete proving
test.
