9
Inspection and maintenance
Logano plus GB402 - Subject to technical modifications!
42
9.3.2
Carrying out the leak test
B
Close the main fuel shut-off valve.
B
Undo threaded plug on test nipple by two turns.
B
Push the test hose of the U-tube pressure gauge onto
the test nipple.
B
Open main fuel shut-off valve, read off pressure and
note it down.
B
Close main fuel shut-off valve and read off the pressure
again after one minute.
B
Calculate the pressure drop per minute through the
differential.
Using the calculated pressure drop per minute and the
test volume (V
test
), refer to the following diagram
(
Æ
Fig. 41) to see whether the gas valve can still be used.
Fig. 40 Checking internally for tightness
1
Test nipple
Fig. 41 Permissible pressure drop per minute for the internal leak test with gas pressure present
x
Test volume in litres
y
Test volume in mbar within one minute
1
Range “Valve tight
”
= applies to new installations
2
Range “Valve adequately tight
”
= valve can be used
without restrictions
3
Range “Valve leaks
”
= valve may not be used
>> check as described in the following
Read-off example
: test volume (V
test
) 5 litres and
pressure drop 4 mbar/min = range 3 “Valve leaks
”
= valve
may not be used >> check as described in the following
If the read-off point for test volume (V
test
) and pressure
drop per minute lies within the range “Valve leaks” (see
read-off example), carry out the test described below.
B
Check all sealed points in the tested pipework section
using a foaming leak detection agent.
B
If required, seal any leaks and repeat the test.
B
If no leaks are found, replace gas valve.
Completing the leak test
B
Remove hose.
B
After completing the test, retighten the screw in the
test nipple.
B
Check the test nipple for leaks.
If you detect a steep pressure drop of
> 10 mbar/minute at a test volume (V
test
)
of < 1, increase the test volume (V
test
). For
this, include the pipework to the next shut-off
valve in the tightness test and repeat the test
using the new test volume (V
test
).
CAUTION:
Risk of system damage due to short circuit.
B
Never spray or let leak detection agent drip
onto cable entries, plugs or electrical
cables/leads.
B
Cover areas at risk before testing for leaks.
