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TROUBLE SHOOTING:
1. Use the contact (stethoscope) module.
2. Touch test area(s): listen through headphones and observe the meter.
3. Adjust sensitivity until mechanical operation of the equipment is heard clearly.
4. Probe equipment by touching various suspect areas.
5. To focus in on problem sounds, while probing, reduce sensitivity gradually to assist in
locating the problem sound at its’ loudest point. (This procedure is similar to the method out-
lined in LEAK LOCATION, i.e., follow the sound to its loudest point.)
NOTE: In diagnosing any type of mechanical equipment, it is important to understand how that equip-
ment operates. Being able to interpret sonic changes is dependent on a basic understanding of the op-
erations of the particular equipment being tested. As an example, in some reciprocal compressors, the
diagnosis of a valve problem in the inlet manifold is dependent on recognizing the distinctive clicking
sound of a good valve vs. the muffled click of a valve in a „blow-by“ mode.
In gearboxes, before missing gear teeth may be detected as an abnormal click, the normal sounds of
gears must be understood. In pumps, certain pumps will have surges, which may confuse inexperienced
operators by the constant shifting of the intensity levels. The surge pattern must be observed before a
lower, consistent bar graph reading can be recognized as the true reading.
Locating faulty steam traps
An ultrasonic test of steam traps is a positive test. The main advantage to ultrasonic testing is that it iso-
lates the area being tested by eliminating confusing background noises. A user can quickly adjust to
recognizing differences among various steam traps, of which there are three basic types:
mechanical, thermostatic and thermodynamic.
When testing steam traps ultrasonically:
1. Determine what type of trap is on the line. Be familiar with the operation of the trap. Is it
intermittent or continious drain?
2. Try to check whether the trap is in operation (is it hot or cold? Put your hand near, but do not
touch the trap, or, better yet, use a non-contact infrared thermometer).
3. Use the contact (stethoscope) module.
4. Try to touch the contact probe towards the discharge side of the trap. Press the trigger and lis-
ten.
5. Listen for the intermittent or continuous flow operation of the trap. Intermittent traps are usually
the inverted bucket, thermodynamic (disc) and thermostatic (under light loads). Continuous
flow: include the float, float and thermostatic and (usually) thermostatic traps. While testing in-
termittent traps, listen long enough to gauge the true cycle. In some cases, this may be longer
than 30 seconds. Bear in mind that the greater the load that comes to it, the longer period of
time it will stay open.
In checking a trap ultrasonically, a continuous rushing sound will often be the key indicator of live steam
passing through. There are subtleties for each type of trap that can be noted.
Use the sensitivity levels of the Sensitivity election Dial to assist your test. If a low pressure system is to
be checked, adjust the sensitivity UP toward 8; if a high pressure system (above 100 psi) is to be
checked, reduce the sensitivity level. (Some experimentation may be necessary to arrive at the most
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