If an ultrasonic leak detector works in outer space in the hands of an astronaut, can it do the job on the ground when operated by an HVACR service technician? Yes, said a Westminster, MD-based manufacturer whose small, handheld leak detector has been used in both applications.

CTRL Systems has developed the CTRL UL101, which last summer was sent, via the Space Shuttle Atlantis, to be used on board the International Space Station. According to the manufacturer, the detector was quickly put to work.

NASA’s Johnson Space Center in Houston, TX, reported a possible leak in an air lock at the space station where astronauts don spacesuits. Astronauts activated the detector and turned around in the air lock, scanning the volume to pinpoint the leak using a conically shaped “Concentrator” attachment. They then relayed information to ground personnel.

The solution in this case was to close a valve and leave the connection unrepaired. The crew worked around that situation and projects stayed on schedule.


In more conventional uses, the CTRL UL101, which is 9.2 inches long, is connected with a wire to an industrial-grade headset worn by a technician. The unit converts ultrasonic signals to audible sounds.

Bob Roche, CTRL’s CEO, said training for the device “is quick, but there is a learning curve.” He said that the key is to distinguish between the ultrasonic sounds of a good piece of equipment and those of a faulty one. “For example, have a technician listen to a good ball bearing and then listen to a bad one. Having a technician listen to both will imprint the melody into the brain. The sound differences are huge. Once you hear the sound of a normal bearing, an abnormal one will stand out.”

HVACR applications for which the manufacturer said the detector can be used include cooling system leaks, steam traps, condensers, refrigeration and heating systems, vacuum leaks, valves and fittings, hoses, and piping and lines. The manufacturer said the detector can be used as an early warning device to fend off possible costly repairs and downtime.

Said Roche, “The UL101 uses the properties of ultrasound to improve the speed and accuracy of component condition assessment and leak detection. It detects ultrasound produced by operating systems and converts it into readily recognizable sounds.”


He added that the unit can work in extremely noisy environments, “allowing you to isolate and differentiate current and potential defects prior to their becoming recognizable to the human ear. Downtime, repairs, and preventive actions may be scheduled in order to minimize cost and production losses.”

The detector has various attachments that improve its performance in different circumstances. One attachment, the Mini-Concentrator, allows the UL101 to pinpoint problems and failures further away, narrows the angle of reception of the ultrasound, and blocks out competing audible and ultrasound noises, according to the manufacturer.

“Once ultrasonic emissions have been detected with the Mini-Concentrator,” said Roche, “our Acoustic Tip attachment can then be used to pinpoint the exact source of the ultrasonic emission. One example is detecting leaks in a piping system. The operator can pinpoint the leak to a one-quarter- to one-half-inch area by attaching the Acoustic Tip to the receiver, and moving it along the length of the piping.”

He added that the configuration helps detect ultrasonic emissions from pressure and vacuum leaks, including steam and gas leaks and electrical arcing.

Another attachment, the PowerBeam 300, can be used to test at a farther distance. This component can detect ultrasound up to 300 feet away and is convenient for testing components that are in difficult-to-reach locations, the company said.

For more information, contact CTRL Systems at 410-876-5676 or www.ctrlsys.com (website).

Sidebar: Justifying The Price Of Ultrasonic Leak Detectors

Cost justification of any detection device or tool is always an important issue. Ultrasonic leak detectors normally carry a higher price tag than other methods, such as soapsuds and gas sniffers. CTRL Systems suggests that contractors and technicians take a look at the advantages of ultrasonic technology and weigh those in leak detector purchasing decisions.

Here are some excerpts from a technical paper prepared by the CTRL Systems on the topic.

“An ultrasonic detection device is a tool that provides added capabilities, complementing (and sometimes replacing) methods such as soapsuds and gas sniffer testing. It often ‘hears’ and locates leaks that can’t be detected (with other methods) because of gas saturation or air movement in the area of inspection. Ultrasonic technology complements existing leak testing methods, but provides added benefits.

“An ultrasonic detector can perform even when there is gas saturation or in windy conditions found on rooftops. With an ultrasonic detector, a technician can scan the entire system within minutes and detect any leaks strong enough to create ultrasound. An obvious rushing sound is an indication of a strong leak to atmosphere.

“Other leaks to atmosphere, especially under high pressure, may reveal themselves with a ‘snap, crackle, and pop’ sound similar to static. These leaks can then be traced with a detector to its source to identify the nature of the sound and repairs needed. Leaks as small as 1/2-ounce per year have been successfully located with an ultrasonic detector.

“An ultrasonic detector can also be used to test nonpressurized components such as a filter-drier when used in conjunction with an ultrasonic transmitter. Testing would be performed in the following manner:

“1. Open the housing and remove the filter cores.

“2. Insert the activated transmitter and close the housing.

“3. Using the detector, scan all brazed joints and the shell casing to detect the highest intensity ultrasound in order to pinpoint the location of the leaks.

“4. After any leaks are found and repaired, the component can be tested again to confirm that the repair is complete.

“An ultrasonic detector can also be used to detect vacuum leaks in the same method as when detecting leaks to atmosphere.”

Publication date: 08/05/2002