Code of Practice to eliminate halocarbon emissions from refrigeration and air conditioning systems: chapter 4

4.0 Servicing

4.1 System Start-up

Before starting the system, the technician should be familiar with the manufacturer's installation, operating and maintenance manuals, this code of practice, and all applicable regulations and standards. The objective of the start-up is to verify that all components and controls are in working order through functional performance testing. The following are good practices:

Refer to Section 4.8-Charging and to the manufacturer's charging instructions to complete the commissioning. If the system is pre-filled, follow the manufacturer's instructions for start-up.

4.2 Preventative Maintenance

Developing and implementing a preventive maintenance plan for all the air conditioning and refrigeration assets will benefit the environment and prolong the life of the system. The following should be considered in developing and implementing a preventive maintenance plan:

4.3 Inspection

A frequent walk-around is a simple, cost-effective manner of minimizing cooling system failures and refrigerant releases. The following verifications on cooling systems should be considered as applicable to each particular system:

4.4 Leak Testing

While an annual leak test shall be done in accordance with the regulations, the manufacturer's recommendations should be considered as part of the organization's preventive maintenance plan. It is essential to perform a leak test at least once a year and in accordance with applicable regulations, policies and manufacturer's specifications. If the system has a history of leakage, more frequent leak tests should be considered. Small sealed packaged units like window air conditioners, water coolers, vending machines and domestic refrigerators do not need a regular leak-testing program.

When to perform leak tests

As prescribed in the Federal Halocarbon Regulations, 2003, leak tests must be carried out:

Leak-Testing Procedure

In a normal situation, the high and low sides of the system equalize on shutdown. The static pressure normally is enough to locate leaks.

On larger hot-gas type systems, the low-pressure side could be pressurized before leak-testing the evaporator, heat exchanger, thermostatic expansion valve or solenoid valve by short-circuiting hot gas to the low-pressure side. The pressure cannot exceed the pressure of the relief devices.

On sub-atmospheric systems, the evaporator water temperature can be raised a few degrees to facilitate leak testing.

Leak-testing procedure typically includes the following steps:

4.5 System Repair

Identify the location of the leak and carry out the leak-testing procedure using best practices. Before initiating a repair, consult the system's maintenance record to determine if there is a history of leaks, which could indicate that other measures have to be considered.

System repair procedure typically includes the following steps:

Note that if the leak cannot be repaired, the refrigerant has to be recovered and the system disposed of in accordance with applicable regulations.

4.6 Recovery, Reuse, Recycling and Reclaiming of Refrigerants

In accordance with applicable regulations, refrigerant removed from a cooling system may be:

It is prohibited to vent refrigerants to the atmosphere in Canada. The recovery equipment is expected to be in good working order before use. If applicable, the extraction efficiency has to meet the standards set for the jurisdiction in which the work is performed. In the absence of standards, remove as much refrigerant as possible. As a rule of thumb, 90% of the refrigerant can usually be recovered if the compressor is operational; otherwise, 80% could be recovered.

If not contaminated, the recovered refrigerant can be reused in the same system.

Refrigerant Recovery Methods

There are two acceptable methods of recovering refrigerants from cooling systems: active recovery and adsorption recovery. There are two types of active recovery: Type 1 active recovery equipment simply recovers the refrigerant. The refrigerant is returned to the same system or a similar system in the organization. Type 2 active recovery and recycle equipment recovers refrigerants and improves their quality by removing particulate matter, moisture and oil. The refrigerant is of superior quality to that removed by Type 1. This method usually will not remove ultraviolet dyes and sealants. The adsorption recovery method transfers the refrigerant to a container with resin, which is then sent to the supplier to reclaim the refrigerant.

Recovery Equipment

Select the appropriate recovery equipment for the planned work and consider the following best practices:

Refrigerant Recovery Containers

Recovery containers are grey and yellow, and when they are used to recover a refrigerant, they are labeled to identify the refrigerant they contain. Generally, they are not identifiable by the designated ASHRAE refrigerant colour. There are various types of containers: 1) Recovery drums are grey with a yellow cover and are used for liquid refrigerants; 2) Recovery cylinders are grey with a broad yellow band on the top and have a two-way liquid/vapour valve. 3) Ton tanks are also grey with a broad yellow band around the end and are used to recover larger quantities of refrigerant from cooling systems to facilitate the reuse of a refrigerant following servicing. 4) Molecular sieve or resin adsorption containers are not pressure cylinders and are approved by Transport Canada. Recovery containers may be exposed to contaminants that could compromise their integrity. The Transportation of Dangerous Goods Act has specifications for refrigerant recovery containers.

Refer to Section 4.10 - Handling and Storage of Refrigerants for more information on refrigerant containers.

Recovery Procedure

A recovery procedure typically includes the following steps:

Under the Federal Halocarbon Regulations, 2003, if the system will be disposed of, it has to be labeled to indicate that the refrigerant has been removed. If the recovered refrigerant is contaminated, the container should be sent to be reclaimed or disposed of in accordance with applicable regulations.

It is best practices to warm the system using the oil sump heater or with indirect heat to recover refrigerant from oil before it is removed. Open flame cannot be used. Oil in the crankcase can also be heated to vaporize residual refrigerant. For low-pressure systems, the evaporator temperature can be raised using hot water.

4.7 Cleaning

Repairing a system after it has been contaminated by a hermetic compressor failure or conversion of systems from HCFC/mineral oil to HFC/polyolester oil typically includes a thorough cleaning by flushing. Older servicing equipment may not be compatible with new refrigerants, and therefore new hoses, seals and O-rings may be necessary.

Generally, the procedure is as follows:

  1. Test for leaks.
  2. Remove refrigerant.
  3. Remove oil.
  4. Flush system.
    • Use procedures recommended by the manufacturer.
    • Use a non-ozone-depleting flushing agent approved for the refrigerant and oil being cleaned.
    • Use a liquid flushing agent from a pressurized container, since flushing agents in open containers can be contaminated with the moisture in the air. Biodegradable flushing agents with boiling points in the order of 85 to 90°C (185 to 195°F) work efficiently and thoroughly.
    • Flush system until the flushing agent is contaminant free. Note that flushing will remove both the refrigerant and oil.
  5. Remove flushing agent.
    • Draw a vacuum to 500 mm Hg (20 in Hg) to ensure that the entire flushing agent has been removed.
  6. Change components.
    • Conversion kits may be available, particularly for domestic systems. Dismantle the system one section at a time and change components as necessary. Consider replacing the filter-dryer. It is best practice to replace any removed gaskets with new ones that are compatible with the refrigerant and oil.
  7. Reassemble system.
  8. Test for leaks.
  9. Charge.
    • Charge the system immediately with refrigerant and oil using the approved procedures, or seal if not in use to prevent atmospheric contamination (refer to Section 4.8 - Charging).
  10. Test for leaks.
    • Run the system for the recommended time and perform another leak test.

      Small systems:

    • Recheck for leaks after 4 to 8 hours of operation.

      Other systems:

    • Recheck for leaks after 24 to 48 hours of operation (refer to Section 4.4 - Leak Testing).
  11. Document.

Other systems

Auxiliary receivers or specially approved ton tanks may be used to recover larger quantities of refrigerant from cooling systems to facilitate the reuse of the refrigerant charge after servicing. It is best to clean each section of a system separately. Consider taking the component to be cleaned off-site.

4.8 Charging

Generally, the procedure is as follows:

4.9 Sealants

When added to a refrigerant, a sealant may slow a leak in a system, but it will not completely fix it. The sealant will seep out of any small holes or cracks along with the refrigerant and, on contact with air, will solidify and seal the hole. Sealants only work when the system is operating.

Because a sealant will continue to do its job on subsequent small holes and cracks, it may conceal the deterioration of a component of a system and lead to a large leak in the future. Therefore, sealants should only be considered for the following:

Before using a sealant:

When adding a sealant:

4.10 Handling and Storage of Refrigerants

Various types of containers are used to store virgin or recovered refrigerants in the liquid or gas state. They vary in size, shape and pressure rating. Refrigerant containers can be colour-coded to identify which refrigerant or blend they contain. All refrigerant containers should meet the Canadian Transport Commission specifications under the federal Transportation of Dangerous Goods Act.

Containers for Refrigerants in the Liquid State

Drums can be used to store liquid refrigerants such as R-22. Some are returnable.

Containers for Refrigerants in the Gas State

A pressure vessel is a refrigerant container of a capacity of more than 28 litres (1 cubic foot). The designed maximum working pressure, carrying capacity and expiry of the pressure certification is stamped on the cylinder.

Refillable refrigerant cylinders can only be used by refrigerant manufacturers for virgin refrigerant and need to be visually inspected and re-qualified as stated in the applicable jurisdiction. Many of the refillable refrigerant cylinders sold in Canada are white with a label that is colour-coded and/or that indicates which refrigerant the cylinder contains. Disposable cylinders only have a one-way valve and are not appropriate for refrigerant in a gas state.

Refer to Section 4.6 - Recovery, Reuse, Recycling and Reclaiming of Refrigerants for information on refrigerant recovery containers.

Storage of Refrigerants and their Containers

Good practices for refrigerant containers usually include:

Storage, handling and servicing areas are:

In addition to general handling and storage practices, fire protection requirements for refrigerants that are flammable have to be incorporated, including the following:

Handling and Transfer of Refrigerants

Handle refrigerant containers carefully, avoiding dragging, dropping and denting, and secure containers into place. When not in use, close container valves and screw on the valve outlet cover nut or cap.

Use a pump and weigh scale when transferring refrigerant in order to prevent releases and to prevent overfilling the container. A pressure differential can be established between the containers using a pump or by heating the discharge container under controlled conditions. The discharge container can be indirectly heated by warm water or forced warm air to a maximum of 49°C (120°F). Do not use direct heating, with the exception of plug-in charging cylinders (dial-a-charge). Avoid mixing refrigerants in one container. Ensure the container is colour-coded and labeled accordingly.

Handling procedures for refrigerants that are flammable are similar to those for other flammable substances:

Storage and Shipping of Equipment

Consider storing and shipping systems with dry nitrogen or dry air (-40°C dew point) as a holding charge.

4.11 Release Reports

The Federal Halocarbon Regulations, 2003 and most Canadian jurisdictions have halocarbon release reporting requirements for cooling systems. Some require that releases over a certain weight, usually 10 kg(22 lb), be reported to the authorities.

4.12 Record Keeping

According to the Federal Halocarbon Regulations, 2003, owners have to maintain a service log to record the installation, servicing, leak testing, charging or other work on cooling system that could result in the release of a halocarbon. Records may also be kept on refrigerant storing containers. The service log has to be updated each time the system is serviced. Forms are available on Environment Canada's website. Ideally, an up-to-date service log would be kept close to the system. A copy can be attached to service contracts for background information on the history of servicing and preventive maintenance.

Consumption Reports

Some jurisdictions require annual reports of refrigerant consumption.

Record Retention

The Federal Halocarbon Regulations, 2003 and some jurisdictions require that owners keep, for a specified period of time, all service logs, notices, records and reports on the site where the cooling systems are located.

4.13 Conversion of a System to an Alternate Refrigerant (Retrofit)

One of the best ways to reduce the environmental impact of ozone-depleting substance releases is to convert the air conditioning or refrigeration system to a system that uses a refrigerant with a significantly lower, or zero, ozone-depleting potential.

Owners of multiple cooling systems should consider developing a long-term strategic plan to upgrade their air conditioning and refrigeration assets.

Ensure that a person knowledgeable in the cooling industry participates in the decision-making process. When deciding whether or not it is beneficial to retrofit a cooling system, owners can consider taking the following steps:

If it is determined that retrofitting the existing cooling system is the best alternative, consider the following in the selection of an alternate refrigerant and oil:

Conversion of a system operating with CFC/HCFC refrigerant to HFC refrigerant may lead to:

Conversion of a system operating with HFC refrigerant to hydrocarbons refrigerant may lead to:

A conversion kit may be available from the manufacturer to assist in the conversion of a system. It may even be specific to the model and application. Retrofitting a system may be an opportunity for using improved components, such as high-efficiency motors or more efficient condensers.

Retrofit steps to follow:

4.14 Shut Down

For a system greater than 19 kW(5.6 tR) that has to be shut down for more than six months, consider isolating the refrigerant in the system's receivers or removing it to approved storage containers.

Where a system has had its refrigerant removed, and that system may be used again in the future, it can be charged with dry nitrogen to help prevent its contamination. Note that ideally all the moisture would be remove from the nitrogen. Storing out of service small cooling systems inside a heated building should be considered.

4.15 Decommissioning

When decommissioning, putting out of service or disposing of equipment, the following steps need to be considered:

Domestic appliances (for example, refrigerators) that contain a refrigerant should be handled with care and they may have to be brought to a pre-assigned site for the recovery of the refrigerant and oil. In some cases, the refrigerant can be removed first, in accordance with applicable regulations.

4.16 Disposal of Refrigerant

When a refrigerant is contaminated and can no longer be used, return it to:

The oil has to be disposed of in accordance with provincial and territorial regulations. Note that blends can be returned to certain facilities.

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