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Procedure for valve check:
1. Use stethoscope module.
2. Touch downstream side of valve and listen through headset.
3. When necessary, if there is too much sound, reduce sensitivity.
4. For comparative readings, usually in high pressure systems:
a. Touch uptream side and reduce sensitivity to minimize any sound (usually bring the meter to
a mid-line "50 %" reading).
b. Touch valve seat and / or downstream side.
c. Compare sonic differentials. If the valve is leaking, the sound level on the seat
or downstream side will be equal to or louder than the upstream side.
Confirming valve leakage in noisy pipe systems
Occasionally in high pressure systems, stray signals occur from valves that are close by or from
pipes (or conduits) feeding into a common pipe that is near the downstream side of a valve. This
flow may produce false leak signals.
In order to determine if the loud signal on the downstream side is c oming from a valve leak or
from some other source:
1. Move close to the suspected source (i.e., the conduit or the other valve).
2. Touch at the upstream side of the suspected source.
3. Reduce sensitivity until the meter displays a mid-line ("50 %") reading.
4. Touch at short intervals such as every 15-30 cm (6 - 12 inches () and note the meter changes.
5. If the sound level decreases as you move towards the test valve, it indicates that the valve is
not leaking.
6. If the sound level increases as you approach the test valve, it is an indication of a leak in the
valve.
