1. Why should I monitor for leaks?
There are several reasons to install leak monitors.
- AHSRAE 15-2001 safety standards for refrigeration systems call for refrigerant monitoring systems to be installed in each refrigerating machinery room. Monitors must actuate air ventilation and visual and audible alarms inside and outside room entrances
- Many refrigerants do not have an odor, can displace oxygen and can generate toxic fumes if exposed to flame
- Many refrigerants are toxic at various concentrations and represent a possible threat to the environment
- Fast detection and repair protect HVAC/R systems
2. Are calibrated leak testers available to confirm monitor is calibrated correctly?
Ritchie Engineering does not sell calibrated leak testers, but gases for testing leak monitor installations are available through:
MSA Mine Safety Appliances
121 Gamma Drive
Pittsburgh, PA 15238-2919
3. What refrigerants will the leak monitors detect?
Leak monitors will detect most common CFCs, HFCs and HCFCs, as well as R-11, R-12, R-13, R-22, R-113, R-123, R-134a, R-404A, R-407C, R-410A, R-500, R-502 and R-507. Leak monitors are also available for ammonia and hydrocarbon- based refrigerants.
4. Can the leak monitor be calibrated for specific applications?
Yes, contact customer service for your specific need.
5. If the unit goes into alarm, can it switch on the fan? Can it turn off the system at the same time?
The leak monitor has a pair of dry, normally open/normally closed contacts that can handle 10 amps at 115 volts. When the sensor indicates a gas presence higher than the set point, it opens the closed contacts and closes the open contacts, which will turn equipment on or off.
6. After a unit goes into alarm and the contacts close, what can it be connected to?
The open contacts can shut the system down, call a phone number, turn on a fan or emergency light, etc.
7. How does the sensor work?
When the sintered metal oxide surface within the sensor absorbs gas molecules, electrical resistance is reduced in the surface allowing electrons to flow more easily. The system controller reads this increase in conductivity and signals an alarm. Metal oxide technology is proven for stability and performance.
8. What is the detection sensitivity level of YELLOW JACKET fixed monitors?
The dual sensitivity system has a low alarm level of about 100 ppm and a high alarm level of about 1000 ppm for most CFCs, HFCs and HCFCs. The high level for R-123 is an exception at about 300 ppm. Ammonia detection levels are about 100 ppm low and 150 ppm high. The alarm level of all YELLOW JACKET single level systems is about 100 ppm.
Detection levels are preset at the factory to cover most situations. If necessary, however, you can order a custom level, or adjust the set point on site.
9. What concentration must be detected?
A monitor with a detection threshold of about 100 ppm for any gas provides an early warning so that repairs can be made quickly.
10. Will the system need recalibration?
Factory calibration should be adequate for five-to-eight years. Routine calibration is unnecessary when used with intended refrigerants. YELLOW JACKET sensors are stable long-term and cannot be poisoned or show negligible drift. You should, however, routinely check performance.
11. Can there be a false alarm?
For monitoring mixtures, the semi-conductor must be able to respond to molecularly similar gases. With such sensitivity, false alarms can be possible. YELLOW JACKET monitors are engineered to help minimize false alarms:
- The two level system waits about 30 seconds until "certain" that gas is present before signaling
- At about 100-1000 ppm calibration level, false alarms are unlikely
To prevent an unnecessary alarm, turn off the unit or disable the siren during maintenance involving refrigerants or solvents. Temperature, humidity or transient gases may occasionally cause an alarm.
12. My central A/C unit has been leaking. The tech did a Nitrogen pressurization hold test, but did not find any lost. It's recharged and now, leaking again. What else can be done?
Some leaks don’t appear until they are exposed to the pressure, temperature, and vibration of a running system. The technician may need to add UV dye to find the leak.