Refrigerant monitors are useful as a maintenance aid and in many applications are required as a safety device.
This page is written to help the user support an existing system, whether it be quarterly PM or troubleshooting a suspected faulty monitor.

When in doubt, call SenTech Technical support for help.  The most important information on this page is our phone number:

  1. Keep your monitor running well - Perform quarterly preventative maintenance:

    Inspect the filters at the ends of sample and reference air tubes.  These are sintered brass filters that will tarnish with age.  Tarnish will not affect the performance.  Replace these filters when they get dusty or dirty.  These should last 2-3 years on an IR-SNIF-MCD and should last about a year on an IR-SNIF-1,2,3. 

    On an IR-SNIF-MCD, inspect the internal five micron filter.  This is a white ceramic cartridge inside the clear polycarbonate bowl.  It is clean when it is 'paper-white'.  When it goes off-color or gray, replace it.  This should last 6-12 months.  

    Give the monitor a 'bump test' with a deminimus release of refrigerant or aerosol.  Note that as of 2019, most keyboard dusters are still pure refrigerant.  Look for the ingredients tetrafluoroethan or difluoroethane.  If the montior does not seem to detect refrigerant, contact SenTech technical support for help.  Do not give it more refrigerant... all that accomplishes is to saturate your lines with refrigerant and waste resources.  
  2. Evaluate a suspect Monitor - Assess a monitor that you suspect is alarming when there is no leak:

    First, the easiest answer is to call SenTech for techncial support.  We can walk the user through step by step troubleshooting and quickly asses the health of your monitor.  

    Is the monitor new?
      Look for a mistake in the installation.  The most common problem with a new monitor is damage caused by using a hole saw to cut conduit holes in the monitor.  We are revising our monitor to include precut conduit holes to eliminate this potential problem.  If damaged, the monitor will usually fail the end-to-end system test.  If your monitor fails the end-to-end test, call SenTech for technical suport.  

    If a new monitor responds to refrigerant, but doesn't turn on audible or visual alarms, look to see that the alarm wiring is correct.  Some installers make the mistake of thinking that the alarm relay provides power to the alarms.  Remember, a relay is just a light switch.  Jumper power to one side of the relay, and then run switched power from the other side of the relay to the alarm.  

    Is the monitor alarming only in one area?  The most simple explanation for this is that there truly is a leak in the room.  Many installers are surprized when their monitor detects refrigerant in a room that has never had a monitor.  

    Is the monitor an existing installation?  We can assume that the problem is not caused by the specifics of the installation, and simple troubleshooting can help.

    Trouble alarm?  Does the monitor energize the middle alarm first, and does it show the word "'Trouble" on the third line of the display? This is an indication that there is a fault in the monitor.  the most common trouble alarm occurs after 3 or 4 years, and indicates a failed diaphragm pump.  Press the reset button on the front of the monitor. The display should show any refrigerant alarms or will show "no more alarms, check for trouble alarms".  From this screen press the right arrow button to display the specific trouble alarm.  If the pump has failed, the monitor will say so, and when the right arrow is pressed again, the monitor will tell every area that has a flow failure.  This second screen is helpful in case only one sample area has a blocked or damaged tube.

    Alarms and the user is sure there is not a leak?  The most common cause of an alarm when there is not a leak is that refrigerant or used oil is being stored in the room.  An oil leak on a machine can easily cause a 100 ppm alarm in a room.  Another item to consider is that a small leak might not be considered significant, but will still cause an alarm in the room.  The goal of using a refrigerant loss monitor as a maintenance tool is to keep finding and fixing smaller and smaller leaks to tighten up the equipment until even 'small' leaks are fixed.
  3. Call for help:  As stated above, sometimes the first, easiest troubleshooting is to call SenTech for technical support:  317-596-1988 or 888-248-1988

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