Carrying Out A Leak Test - Buderus Logano plus GB402 Installation And Maintenance Instructions For Contractors

10 Inspection and servicing

10.3.2 Carrying out a leak test

▶ Turn off appliance shut-off valve.
▶ Undo threaded plug on test nipple by two turns.
▶ Push the test hose of the U-tube pressure gauge onto the test nipple.
▶ Open the gas appliance shut-off valve and wait for the pressure to
stabilise.
▶ Note and record the pressure.
▶ Close the appliance shut-off valve and check the pressure again a
minute later.
▶ Calculate the pressure drop per minute from the differential.
Using the calculated pressure drop per minute and the test volume
(V ), refer to the following diagram ( Fig. 41) to see whether the gas
test
valve can still be used.
Fig. 41 Permissible pressure drop per minute for the internal leak test with gas pressure present
[1] "Valve tight" range = applies to new installations
[2] "Valve adequately tight" range = valve can be used without
restrictions
[3] "Valve leaks" range = valve may not be used
>> perform a test as described in the following
x Test volume in litres
y Pressure drop in one minute in mbar
Read-off example: test volume (V
4 mbar/min = range 3 "Tap leaking" = tap may not be used >>
carry out test as described below
If you detect a steep pressure drop of > 10 mbar/minute
at a test volume of (V
(V ). For this include the pipework up to the next
test
shut-off valve in the leak test and repeat the test using
the new test volume (V
If the read-off point for the test volume (V
minute lies within the "Valve leaks" range (see read-off example), you
must carry out the test described below.
DANGER: Risk of system damage due to short circuit!
▶ Never spray or let leak detection agent drip onto
cable entries, plugs or electrical cables/leads.
▶ Cover areas at risk before testing for leaks.
▶ Check all joints in the tested pipework section using a foaming leak
detection agent.
▶ If required, seal any leaks and repeat the test.
▶ If no leaks are found, replace gas train.
34
) 5 litres and pressure drop
test
) of < 1, increase the test volume
test
).
test
) and pressure drop per
test
Fig. 40 Checking internally for tightness
[1] Test nipple
Completing the leak test
▶ Remove hose.
▶ After completing the test, retighten the screw in the test nipple.
▶ Check the test nipple for leaks.
Logano plus GB402 – 6 720 820 700 (2018/01)