Leak Testing

One key element is the Proper Leak Testing Procedure. Here it is:

Venting Prohibited

You must eliminate the practice of venting any regulated refrigerant. In addition, it is mandatory to leak test by not adding any regulated refrigerant(s), including all ozone depleting and most climate change designated refrigerants (see Manitoba Ozone Depleting Substances and Other Halocarbon Regulation – MR 103/94 for the designated list). It is common industry standard to use nitrogen and/or soap & water. Other methods are acceptable (see below).

Please note that it is also good practice to recover un-regulated refrigerants. Some of these substances are potentially harmful as greenhouse gases and/or may be harmful to human health or the environment.

Separate recovery units are required to contain different refrigerants. Cross contamination of refrigerant gases may cause air conditioning equipment damage if it is replaced in a unit. Mixing of refrigerants is contrary to the Regulation.

Approved Leak Testing Methods

Under the Manitoba Regulation 103/94, no person shall recharge or top-up equipment that contains an ozone depleting substance (ODS) unless the person first conducts a leak test and repairs the identified leak permanently.  Technicians may choose one or more of the following leak test methods to ensure a units system is/will work effectively after any ODS is added following the system’s repair.  The following is the prescribed leak test procedure and list of acceptable leak testing methods recognized by Manitoba Environment.  They are subject to change.

Prescribed Leak Test Procedure:

  1. If the system still contains a regulated refrigerant, proceed to #3.
  2. If the system has lost its charge and no longer contains an regulated refrigerant, it must fist be pressurized to a minimum of 150 psi (1034 kPa) or such a pressure as not to rupture the system using dry nitrogen.
  3. Use one of the appropriate method(s) indicated under “Acceptable Leak Testing Methods” to detect the presence and location of the leak(s).
  4. If no leak is detected after fully and thoroughly leak checking, you may recharge the system with the appropriate or manufacturer designated refrigerant.
  5. If a leak is found, isolate that component(s), if possible.  Recover any refrigerant from the component or system.
  6. Once any remaining refrigerant has been recovered, repair or replace the component or system.
  7. Perform another leak test method to confirm that the leak has been repaired.  If any leaks are found, repeat #1-7 until all leak(s) have been repaired.
  8. Evacuate the system in accordance with the manufacturer’s recommended evacuation/dehydration levels. When the manufacturer’s information is unavailable evacuate to 29.87 in Hg. (550 microns) and hold for a minimum of 10 minutes (as described in the “Acceptable Leak Testing Methods” Standing Vacuum Test).
  9. The system has now been evacuated and dehydrated. The system must now be recharged using the accordance with the Manufacturers Certified Installation, Specifications and Service Manuals and the Environmental Code of Practice for the Elimination of Fluorocarbon Emissions from Refrigeration and Air Conditioning Systems (published by Environment Canada). These items are subject to the Minister’s approval and amending and updating.
  • An ozone depleting substance (i.e. HCFC-22, HFC 134a or any other) must not be added to nitrogen or dry air for use as a trace gas. However, you may use the remaining (remnant) gas that was in the system to immediately check for leaks.

 

Acceptable Leak Testing Methods

There are many different techniques for leak testing, with varying degrees of accuracy depending on the system being tested. The following guidelines are acceptable procedure for leak testing on various stationary refrigeration and air conditioning systems.

The following techniques have been identified by MOPIA and are acceptable by the Minister of Conservation. The most appropriate leak test method for the circumstance should be chosen and performed by a Manitoba certified individual (“trained service technician”).  The completing of a leak test is not a guarantee against leaks in the future, and therefore is not meant to replace any existing preventative maintenance program.

1.         Electronic leak detection
2.         Halide flame leak detection
3.         Soap and bubble test
4.         Ultrasonic leak detection
5.         Fluorescent dye leak detection
6.         Standing Vacuum test
7.         Standing nitrogen pressure test

Note: Any additional leak testing technologies that are developed and find acceptance within the refrigeration and air conditioning industry may become acceptable and added to these guidelines.  They must first be approved by the Minister of Conservation.  It is recommended that you periodically check with MOPIA for the latest list of acceptable leak test procedures.

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