EPA 430-B-11-001 

 

GreenChill Best Practices Guideline 

Commercial Refrigeration 

Leak Prevention & Repairs 

U.S. Environmental Protection Agency 

Stratospheric Protection Division 

May 2011 
 

 i 

DISCLAIMER

This document does not address or assert compliance with the statutory requirements of Section 

608, Title VI of the Clean Air Act, as amended in 1990. Nor does this document address or assert 

compliance with the EPA Section 608 leak repair regulations, at 40 CFR Part 82, Subpart F. 

The authors of this Guideline, and the companies, agencies, and organizations to which they 

belong, do not assume responsibility for any omissions or errors, or assume liability for any 

damages, that result from the use of this Guideline. 

Always check with your equipment manufacturers for proper procedures for your equipment 

before undertaking any action that may affect your equipment. 
 

 ii 

TABLE OF CONTENTS

I. INTRODUCTION ..................................................................................................................... 1

Mission ....................................................................................................................................... 1

Purpose and Scope .......................................................................................................................... 1

Refrigerant Leaks from Supermarket Refrigeration Systems .......................................................... 2

II. WHY SYSTEMS LEAK ......................................................................................................... 3

Where Leaks Occur ......................................................................................................................... 3

Compressor Racks .................................................................................................................................. 3

Display Cases ......................................................................................................................................... 4

Remote Air-Cooled Condensers ............................................................................................................. 4

Walk-In Evaporators .............................................................................................................................. 5

Field-Installed Piping ............................................................................................................................. 5

Condensing Units ................................................................................................................................... 5

Remote Headers ..................................................................................................................................... 5

Causes of Leaks............................................................................................................................... 6

III. GETTING STARTED ........................................................................................................... 9

No-Tolerance Policy ....................................................................................................................... 9

Tracking Leaks ................................................................................................................................ 9

IV. PREVENTIVE MAINTENANCE PRACTICES .............................................................. 10

Clean Equipment ........................................................................................................................... 10

Leak Detection Alarm Systems ...................................................................................................... 11

Regular Leak Inspections .............................................................................................................. 11

V. LEAK REPAIRS .................................................................................................................... 12

Response Time .............................................................................................................................. 12

Thoroughness of the Check ........................................................................................................... 12

Follow Up Checks and Verification .............................................................................................. 12

VI. REDUCING LEAK POTENTIAL ..................................................................................... 13

Overcharged Systems .................................................................................................................... 13

System Component Upgrades ....................................................................................................... 13

Additional Recommendations ....................................................................................................... 13

APPENDIX A. SUPERMARKET WALK-THRU CHECKLIST ......................................... 15

APPENDIX B. MONTHLY REFRIGERANT RECEIVER LEVEL CHART 2011-2012 . 17
1 

I. Introduction 

Mission 

GreenChill’s mission in developing this document is to assist food retailers in reducing 

refrigerant leaks in their commercial refrigeration systems. 

Purpose and Scope 

The purpose of this Best Practices Guideline is to provide food retailers with information on best 

practices for reducing refrigerant leaks from commercial refrigeration systems. The Guideline 

only covers practices implemented during the design and operation of a refrigeration system and 

does not discuss leak prevention practices during the installation of equipment. Information on 

leak-tight installations can be found in GreenChill’s Best Practices Guideline: Ensuring LeakTight Installations of Refrigeration Equipment.

1

While GreenChill preferably encourages the adoption of advanced refrigeration as a means for 

reducing refrigerant emissions, the partnership also recognizes the importance of proper 

servicing and maintenance practices in refrigeration management strategies. This Guideline 

document focuses on practices largely relevant to traditional centralized direct expansion (DX) 

systems; however, most practices also are applicable to other system types such as distributed 

systems and secondary loop systems. Specifically, the Guideline provides information on the 

following: 

• Why systems leak; 

• Tracking refrigerant charges; 

• Preventative maintenance practices; 

• Responding to leaks; and 

• Reducing leak potential. 

This Guideline document does not address compliance issues associated with EPA regulations 

promulgated under Title VI of the Clean Air Act, as amended in 1990, including the regulatory 

leak repair provisions under Section 608 of the Clean Air Act. 

 

1

 Available at http://www.epa.gov/greenchill/downloads/LeakGuidelines.pdf 
 2 

Table 1: ODP and GWP of Common 

Refrigerants 

Refrigerant ODP GWP 

CFC-12 1 10,900

R-502 0.25 4,646

HCFC-22 0.055 1,810

HFC-134a 0 1,430

R-404A 0 3,922

R-507A 0 3,985

R-407A 0 2,107

R-410A 0 2,088

R-744 (CO2) 0 1

Source: IPCC (2007), Montreal Protocol 

Refrigerant Leaks from Supermarket Refrigeration Systems 

Traditionally, supermarket refrigeration systems are characterized by large refrigerant charge 

sizes and potentially high leak rates, a combination that results in considerable refrigerant 

emissions. EPA estimates that a centralized DX system can emit as much as 25% of its 

refrigerant charge annually.2

 However, through best practices and the adoption of advanced 

technologies, GreenChill members have shown considerable success in reducing refrigerant leak 

rates. In 2008, GreenChill partners collectively reported an average corporate-wide annual 

emission rate of 12%.3

 Individual partners have also shown that greater leak reduction is 

possible, setting aggressive corporate emission targets of less than 7%. Furthermore, individual 

stores have proven that rates less than 5% are achievable and sustainable with the adoption of 

advanced refrigeration technologies in combination with best practices. 

To encourage supermarkets to reduce leaks, it is first 

important for supermarkets to recognize the negative 

impact refrigerants have when emitted into the 

atmosphere. Commonly used commercial 

refrigerants such as chlorofluorocarbons (CFCs) and 

hydrochlorofluorocarbons (HCFCs) contribute to 

deterioration of the stratospheric ozone layer. CFCs, 

HCFCs, and even the ozone-friendly 

hydrofluorocarbons (HFCs) contribute to climate 

change. Table 1 summarizes the ozone depletion 

potential (ODP) and global warming potential 

(GWP) of commonly used commercial refrigerants 

 

2

 See http://www.epa.gov/greenchill/downloads/EPASupermarketReport_PUBLIC_30Nov05.pdf 3

 The GreenChill partner emission rates described here are calculated according to the methodology in GreenChill's 

program guidance, which uses the ratio of emissions during one year to the system’s refrigerant charge. 

See http://www.epa.gov/greenchill/downloads/GreenChillStoreCertificationProgramGuidance.pdf . This differs 

from the definition of leak rate in 40 CFR 82.152 used to assess compliance with EPA’s regulations. The regulatory 

definition expresses leak rate in terms of the percentage of an appliance’s full charge that would be lost over a 12-

month period if the current rate of loss were to continue over that period. 
 3 

II. Why Systems Leak 

Where Leaks Occur 

Leaks can occur in a variety of locations throughout a supermarket. Figure 1 provides estimates 

from one regional supermarket chain of the portion of refrigerant leaks coming from specific 

sources. Each leak source is explained further below. 

Figure 1: Leak Sources for a Regional Supermarket Chain 

Compressor Racks 

A typical supermarket in the U.S. contains 2-4 parallel compressor racks, each with a number of 

rack-mounted components that are all potential leak sources. Components include 3-8 

compressors; suction, liquid, and discharge manifolds; suction control valves; 3-way valves; 

head pressure controls; suction filters; liquid driers and sight glasses; a liquid receiver; an oil 

separator; a suction accumulator; pressure controls; and numerous shut-off valves. Prime 

locations for leaks include: 

• Pressure controls and their control lines or cap tubes, from vibration, rub-through, or 

mechanical damage; 

• Rack-mounted valves, including 

o Brazed or mechanical fittings, flanges, and threaded pipe fittings on the 

receiver; 

o Valve stem packing, especially if the valve cap and/or cap seal is missing; 

o Control lines, especially high-pressure lines; and 

o Access ports; 

• Filter/drier assemblies, from deteriorated gaskets or loose flange bolts; 

• Manifold tee fittings that are improperly brazed from the factory and subject to vibration 

from the rack; 

• Receiver liquid level gage ports, which leak from deteriorated gaskets; 

• Schrader valves, through their cores, especially if the cap is missing; and 
 4 

• Steel components such as suction accumulators, suction filter shells, steel suction valves 

mounted on the suction line, and even receivers mounted below a suction manifold due 

to corrosion, as seen in Figure 2. 

Figure 2: Excessive corrosion on rack components 

Display Cases 

An average-sized supermarket can contain over one hundred display cases. The potential for 

leaks from display cases is great, due to the large number of leak points in the evaporators and 

expansion valves. Evaporator coils are made up of small-diameter tubing and many soldered 

return bends, making them susceptible to leaks. 

The tubing is subject to physical abuse from thermal stress failure, improperly-brazed return 

bends, metal-to-metal contact from other display case parts, and chemical reactions from food 

acids, especially in service deli cases. Tubing can also be disturbed during the cleaning of a case 

or de-icing of a coil by an untrained employee. 

In older cases, expansion valves with flare nut connections have historically been a source of 

many leaks. Flare nuts are subject to loosening, especially near the evaporator where ice is 

present. Newer cases instead use brazed fittings, which have reduced - but not totally eliminated 

- expansion valve leaks. 

Other potential valve leak sources in a display case include check valves used in hot gas defrost 

systems and solenoid valves that are used for temperature control. Each of these valves can leak 

from the fittings or from the body of the valve itself. 

Remote Air-Cooled Condensers 

Leaks on remote condensers are most common in the finned tube area where the tubes pass 

through a condenser frame member. Manufacturers have tried to eliminate this problem by 

designing the tube sheet to be supported by non-refrigerant-carrying tubes or by using brass 
 5 

ferrules between the tubes and the frame. As a result of thermal expansion or improper rigging of 

the condenser during installation, the brass ferrules can fall out, causing the condenser tube to 

contact the condenser frame, which over time may create a leak. Brazed joints on return bends 

and manifolds are also a potential source of leaks. 

One major cause of significant refrigerant leaks on remote condensers is a failure of the motor 

mount/fan blade assembly. Most manufacturers have improved the design of the fan motor 

mounting to reduce this problem but not totally eliminate it. In many cases the motor mount 

failure is preceded by a failure of the fan assembly. Fan blades are often constructed using a steel 

hub assembly with multiple aluminum or steel fan blades riveted to the hub. Due to cycling of 

the fan motor, over time the rivets on the individual blades may loosen or the blade itself may 

begin to tear. If the fan assembly is not replaced, the blade may detach from the fan hub, causing 

a major imbalance of the fan motor assembly. This extreme vibration may in turn cause the 

motor support bracket to fail and the fan motor assembly to fall into the fin tube surface, 

resulting in major damage to the fin tube assembly and possibly a rupture of one or more 

refrigerant-carrying condenser tubes. 

Receivers mounted under condensers along with liquid drier shells, head pressure valves, and 

other components are subject to the same leaks as those mounted on the compressor racks. Such 

leaks are just more difficult to detect due to the remote outdoor location. 

Walk-In Evaporators 

An average supermarket contains only about sixteen walk-in evaporator coils. The leak points in 

the walk-in coil are similar to those in the refrigerated cases. Walk-in evaporators generally have 

more solenoid valves and check valves than display cases, resulting in a higher leak potential. 

Since walk-in evaporators are accessible and located in an enclosed space, however, leaks from 

these units are more readily detected with a leak detector. 

Field-Installed Piping 

Field-installed piping consists of all suction, liquid, and discharge piping that connects the 

compressor racks, display cases, walk-in evaporators, and remote air-cooled condensers. Leaks 

can occur at any one of the hundreds of brazed connections and thousands of feet of piping in a 

typical store. If care is not taken to isolate the copper piping from the steel support system, 

thermal expansion or vibration can create constant movement of the soft copper tubing against 

the harder steel supports, resulting in development of rub-through leaks over time. 

Condensing Units 

A condensing unit comprises a single compressor, an air-cooled condenser, and a receiver. Like 

compressor racks, condensing units also contain valves, filter/driers, and pressure controls, all of 

which are potential leak sources. 

Remote Headers 

Remote headers are becoming more common in supermarkets to reduce the number of piping 

runs from a central point near the sales area back to the compressor room. In contrast to headers 

installed on compressor racks, remote headers are able to eliminate vibrations and the attendant 
 6 

risk of leaks. While less prone to leaks, they are usually less accessible and might not be checked 

as frequently as a central compressor room. 

Causes of Leaks 

Leaks are caused by the inevitable wear and tear on a refrigeration system as well as poor design 

and improper installation,4

 servicing, and maintenance practices, such as: 

• Poor brazing techniques. Leaks can result from improper brazing techniques such as 

improper cleaning of the joint prior to brazing, using the wrong brazing alloy, and failure to 

heat the joint uniformly or to the proper temperature before filling the joint with brazing alloy.

• Improperly tightened fittings. Leaks occur from threaded and flared fittings either when 

they are not tightened sufficiently or when they are over-tightened and crack.

• Valve caps and seals missing. To reduce leaks through valve stems and Schrader cores, all 

valve stems that are designed to be capped, and all access Schrader valves, must have the 

proper caps in place. Figure 3 provides an example of a Schrader valve without any caps. The 

caps must also have the proper seal or o-ring in place to ensure leak tightness.

Figure 3: Image of a Schrader valve with no caps 

• Material incompatible with oil or refrigerant. Seals exposed to HCFC refrigerants swell at 

a different rate than seals exposed to HFC refrigerants. If a system is being retrofitted from an 

HCFC to an HFC refrigerant, especially if it requires a change in oil from a mineral oil to a 

polyolester (POE) oil, gaskets or seals in the system may need to be replaced.

 

4

 Information specific to leak tightness during installation can be found in GreenChill’s Best Practices Guideline 

Ensuring Leak-Tight Installations of Refrigeration Equipment, available at 

http://www.epa.gov/greenchill/downloads/LeakGuidelines.pdf. 
 7 

• Vibration. Most vibrations in refrigeration systems occur on or near the compressor 

discharge lines and are caused by gas pulsations. If severe, discharge line vibrations can result 

in broken lines or fittings, as seen in Figure 4. 

Figure 4: Image of broken clamp caused by vibrations 

• Thermal expansion and contraction. Refrigeration systems change temperature, resulting in 

expansion and contraction of the refrigeration piping and associated components. For 

example, a 1000 F increase in temperature will expand a 100 foot copper line by over an inch. 

This temperature change is quite common in hot gas defrost suction lines. If the line is 

constrained from freely expanding, thermal stress forces on the pipe may cause it to break 

fittings at the support points. Properly engineered expansion loops are required to absorb 

these thermal stresses. Likewise, constant thermal expansion and contraction can, over time, 

adversely affect the sealing integrity of gaskets and seals used in refrigeration components. 

• Corrosion. Copper evaporator coils in contact with food acids such as vinegar may corrode 

over time and develop pinhole leaks, as seen in Figure 5. Corrosion leaks can also occur on 

compressor rack components from condensation forming or dripping on steel rack 

components. Incompatible or improperly used cleaning materials also cause corrosion. 

Technicians should only use cleaning agents that are compatible with the refrigeration 

components—especially the evaporators and associated piping. 
 8 

Figure 5: 3-year old uncoated service deli coil 

• Metal-to-metal contact of tubing. Copper tubing in direct contact with other tubing or 

harder steel supports or concrete can rub through the tubing wall and create leaks. 

• Improper support of tubing. Improperly supported copper tubing will sag between supports 

or at 90-degree turns, creating unwanted stress. This stress may lead to broken lines or 

fittings, eventually causing leaks. 
 9 

III. Getting Started 

No-Tolerance Policy 

Supermarket employees manage and run their business with the goal of meeting their customers’ 

needs. Although most companies understand the importance of minimizing leaks, competing 

responsibilities often get in the way of making refrigerant management a priority. Identifying 

leaks as a high priority is an important step in ensuring proper maintenance and repair of 

refrigeration systems. Companies should establish a corporate-wide no-tolerance policy for 

refrigerant leaks. Establishing a no-tolerance leak policy increases store managers’ and service 

technicians’ awareness of system maintenance and leak repair. Increased awareness reduces the 

likelihood that leak checks and tests will get overlooked and helps prevent unnecessary leaks. 

In supporting a no-tolerance policy, senior management must openly acknowledge and 

encourage the policy in order to reinforce the message throughout the company and among its 

employees. 

Highlighting savings in both refrigerant and servicing costs will help senior management get on 

board with a no-tolerance policy. Common commercial refrigerants cost between $6-10 per 

pound of refrigerant.5

 Based on these prices and assumed servicing costs, refrigerant leaks could 

cost a supermarket more than $10,000 each year. Clearly, refrigerant leaks are not only harmful 

for the environment but also are bad for a company’s bottom line. 

Tracking Leaks 

In addition to making leak prevention a priority, a supermarket should incorporate a leak 

tracking system into its refrigerant management program. A tracking system enables a company 

to easily quantify leaks, isolate leak sources, and manage refrigerant leaks across multiple stores 

and systems. It also lets a company benchmark its data against industry trends and set and meet 

leak reduction goals. A tracking system also lets a company hold individual stores accountable 

for their leaks and makes it possible to reward store employees, service technicians, or 

contractors for good practices. 

A supermarket can use either a manual leak tracking system or tracking system software. 

Tracking software – depending on the type used – can help automate the tracking of refrigerant 

inventories, servicing dates, system capacities, leak amounts and frequencies, and component 

failures. It can also generate automatic alerts if conditions warrant. 

 

5

 Range represents costs of R-22, R-404A, and R-507 on May 20, 2010 from http://www.r22.org/. 
 10 

IV. Preventive Maintenance Practices 

Clean Equipment 

A clean and uncluttered mechanical room provides a safe and accessible environment for service 

technicians and sends a strong signal about a store’s commitment to equipment maintenance and 

leak reduction. Dirty refrigeration compressor racks, air-cooled condensers, remote headers, and 

walk-in evaporator coils make it difficult for technicians to spot leaks and create the impression 

that a store is not concerned with the maintenance of equipment. Motivation of service 

technicians is key to the success of a leak reduction program. To instill a sense of pride in your 

service technicians, refrigeration racks as well as the entire mechanical room should be kept as 

clean as possible. Compressor racks and their components should be free of oil and dirt. 

Corrosion on steel components should be removed and components painted with a rust-inhibiting 

paint to help prevent future corrosion. Mechanical rooms should not be permitted to be used as 

storage areas by the store personnel - besides the obvious safety concerns, the clutter reduces a 

technician’s productivity, adds to his or her frustration, and increases maintenance costs. As a 

result, equipment and mechanical rooms should be cleaned at least annually. Oil spills and other 

substantial messes should also be cleaned as they occur. 

Figure 6: Clean Machine Room at a Farm Fresh Store 
 11 

Leak Detection Alarm Systems 

Each store should have a refrigerant leak monitoring and alarm system to ensure a response to 

major leaks that could develop between regular leak inspections. Leak detection systems are 

either direct or indirect. A direct detection system directly measures the refrigerant in an air 

sample taken near a refrigeration system or one of its components. An indirect system measures 

changes in receiver refrigerant levels, the weight of the condenser/receiver assembly, or system 

temperature. Often the first notification of a refrigerant leak comes from a temperature sensor 

that actuates a temperature alarm as the rack starts to run low on refrigerant. 

One low-cost alarm system that can be easily incorporated into most stores uses a system 

temperature sensor that measures the temperature of the system farthest from the compressor 

rack, which is the first location likely to be affected by a low refrigerant charge. This system 

should be programmed with an alarm temperature as close to set point as possible without 

triggering nuisance alarms. When this temperature alarm is activated, it should be treated as a 

refrigerant leak alarm. Regardless of the type of system chosen, the monitoring system needs to 

be tied to an alarm system that proactively notifies store management of potential leaks. 

Furthermore, levels of redundancy or checks in the alarm system procedure should be in place to 

ensure that the alarm is not ignored. 

Unfortunately, direct central leak detection systems are not ideal in highly-vented locations due 

to the rapid dilution of the refrigerant sample in the ambient air. Since remote air-cooled 

condensers are located outdoors, refrigerant loss from such units can only be detected using an 

indirect leak detection system or during preventative leak checks. Similarly, it can be challenging 

to apply direct central refrigerant leak detection to condensing units with unit-mounted air cooled 

condensers, due to the volume of air changes the condensers require. As a result, regular leak 

inspections are extremely important and should not be overlooked. 

Regular Leak Inspections 

On a regular basis service technicians should check receiver levels, compare refrigerant levels to 

data from the previous visit, and walk through the store with portable device. The GreenChill 

Checklist for a Walk-Thru Leak Check of a Supermarket and the Receiver Refrigerant-Level 

Chart, in Appendix A and Appendix B, respectively, should be used for this purpose. Checks 

should be done every one to two months, based on the size of the system and the system type. 

Large central DX systems need to be checked more frequently while secondary systems with 

mechanical room refrigerant monitoring may be checked less often. 
 12 

V. Leak Repairs 

Response Time 

A supermarket company should establish a corporate policy for responding to a refrigerant leak 

alarm. It should establish both a maximum response time and a process for finding and repairing 

the leak once a service technician is on site. The response time should be as short as reasonably 

possible, normally two to four hours in most areas. In the event of a major leak, large quantities 

of refrigerant can leak out of a system in a short period, so a fast response time could prevent a 

considerable amount of refrigerant from leaking to the atmosphere. 

Under no circumstances should a leaky system be left prior to the identification and repair of the 

leak. If a major component that is not readily available is leaking and needs to be replaced, that 

component should be isolated from the system or given a temporary repair, if possible. Simply 

adding more refrigerant to the system (i.e., topping off the system) is not considered a viable 

solution to addressing a leak. 

Thoroughness of the Check 

In many cases the first refrigerant leak found in a leak check may not be the only leak in the 

system. In fact, it might not be the leak responsible for most of a refrigerant loss. Therefore, each 

technician should understand the correlation between the quantity of refrigerant charge lost and 

the leak rate of the leak found. If the leak found is too small to leak the quantity of refrigerant 

lost, the technician should assume there is another leak in the system and continue the leak 

search. 

Follow Up Checks and Verification 

Once the repair is made, the system should be checked to verify it is leak-free. The verification 

should include a check of the repaired area as well as the receiver level to ensure that no 

additional refrigerant was lost. A drop in receiver level is an indication that there could be more 

leaks in the system. 
 13 

VI. Reducing Leak Potential 

Overcharged Systems 

A refrigeration system may require a “winter charge,” in which more refrigerant is used in the 

winter to permit flooding of the condenser to maintain a minimum operating system head 

pressure. This charge should be kept as small as possible by using split-condenser valves, fan 

cycling, and floating head pressure control. System charges can also vary significantly if the rack 

is piped to a heat recovery coil or uses a gas-type defrost. The total annual refrigerant charge is 

the charge required to feed expansion valves with saturated liquid refrigerant at the time when 

the system charge requirement is at its maximum, and no more. This total annual charge may 

only be needed for a relatively few hours a year and is stored the rest of the time in the system’s 

receiver. As a result, a system could have an excess refrigerant charge in the receiver over 90% 

of the time. 

If a leak occurs during this 90% period, it might be possible to lose the entire receiver charge 

before the refrigerant loss begins to affect case temperatures. To minimize the potential for such 

loss, it is important to document the receiver levels during winter and summer conditions as well 

as when the system is in defrost or heat recovery mode. These levels should be posted on the 

refrigeration rack or in some other convenient location that is readily available to any service 

tech who would be charging the system after a leak. It is common practice for service technicians 

to charge additional refrigerant to a system as a safety buffer. This buffer refrigerant will add to 

the potential loss, and a policy should be instituted to avoid this practice. 

System Component Upgrades 

System components should be replaced with parts that are more leak-resistant or have a reduced 

number of potential leak sources. For example, discharge-piloted evaporator pressure regulating 

(EPR) valves may be replaced with suction stepper valves, which eliminate the high-side control 

line, provide better temperature control, and are generally more reliable. Suction and liquid 

manifolds may be replaced with loop piping systems or remote manifolds to reduce the number 

of fittings subject to rack vibration. During major remodels, you may also want to consider 

replacing centralized DX racks with distributed systems, secondary loop systems, or CO2

systems to further reduce leak potential. 

Additional Recommendations 

A store can further reduce the leak potential of its existing refrigeration system by following 

these recommendations: 

9 Replace flared connection components with brazed connection components. 

9 Replace valves with bolted connections with hermetic one-piece valves with no mechanical 

joints. 

9 Replace valves with control lines with valves that don’t require control lines. 
9 Ensure the proper cap is in place on all valve stems designed to be capped, as well as 

access Schrader valves. The caps should also have the proper seal or o-ring in place to 

ensure leak tightness.

9 Replace fragile cap tube-type control lines with steel lines or armored flexible lines. 

9 Tighten bolts on flanges used to connect valves and filter-drier covers to the proper torque 

and use a new gasket in reassembly. 

9 Eliminate liquid hammer by mounting a sealed vertical tee ahead of the solenoid valve.

9 Use an approved thread sealant to prevent leakage from threads or from corrosion around 

threads. 

9 Conform installations to pipe support spacing recommendations specified in the 2008 

ASHRAE Handbook – HVAC Systems and Equipment.6

9 Protect tubing by creating a space separation or using a cushioning material. 

9 Ensure equipment located in vulnerable environments has epoxy or phenolic coatings on 

fin-tube surfaces, refrigerant piping, or other components that are subject to corrosion. 

Vulnerable equipment may include service deli cases that are in contact with vinegarcontaining products and rooftop condensers that are located near the coastline or a 

chemical plant.

9 Ensure chemical compatibility of cleaning agent with components and materials. 

 14 

 

6

 2008 ASHRAE Handbook – HVAC Systems and Equipment 45.7, Table 6: Suggested Hanger Spacing and Rod 

Size for Straight Horizontal Runs. Adapted from MSS Standard SP-69-2003. 
15 

Appendix A. Supermarket Walk-Thru Checklist 

This checklist should be used to routinely check your store for refrigerant leaks. To complete the leak inspection, 

you will need a hand-held electronic leak detector capable of measuring refrigerant leaks of 1⁄2 oz per year. The leak 

detector should be checked and calibrated at least once a year and preferably more often. Remember, the only way 

to solve refrigerant leaks is to repair them; topping-off your system is not a viable solution! 

1. _______ Receiver Levels: Identify and log the refrigerant level of the receiver of each 

refrigeration system using the GreenChill Monthly Refrigerant Receiver Level Chart (see 

Appendix B). Be sure the refrigeration systems are not in heat reclaim, gas defrost, split 

condenser, or winter flooding mode, or any other condition that could affect receiver level. 

Compare the current refrigerant level with levels logged during previous checks. A drop in 

the receiver level from a previous reading it may indicate a leak in the system. 

**REMEMBER** A significant drop in refrigerant level must be the result of a significant 

leak. Do not stop at the first leak found, especially if it is a seeping connection or valve stem 

leak. Continue searching until a significant leak is found. 

2. _______ Oil Seepage: Visually check the compressor racks, piping, and valves in the 

mechanical room for any oil seepage. If oil seepage is identified, use soap bubbles or an 

electronic leak detector to identify any refrigerant leak and pinpoint the exact location. 

3. _______ Mechanical Room: Using an electronic leak detector at its most sensitive setting, 

slowly move the probe over all components in the mechanical room. Temporarily turn off the 

mechanical room ventilation to reduce air movement. If the detector indicates a leak within 

the space, slowly reduce the sensitivity and progressively move to the leak location until 

found. 

4. _______ High-Pressure Control Lines: Check the control line temperature of all highpressure switches about 12 inches from the compressor connection. If the temperature is 

above the mechanical room ambient temperature, it may indicate a small leak in the control 

line, fitting or control bellows. 

5. _______ Pressure Relief Valves: Check the pressure relief valves of each system for 

refrigerant release. Each relief valve should have a balloon, blow-off cap, or other telltale 

way to signal that a relief valve has discharged. Under normal conditions, a relief valve 

should never discharge. If it has, the cause must be found and corrected and the relief valve 

replaced as they are only designed for one release and may seep refrigerant if left in place. 

6. _______ Air-Cooled Condensers: Visually check all air-cooled condensers for oil seepage 

underneath unit on finned coil surfaces. Check return bends and manifold assemblies for oil 

seepage. If a view of return bends is blocked by a cover, either remove the cover to inspect or 

use an electronic leak detector to probe the area under the cover. If the condenser is 

suspected of leaking, the refrigeration system should be turned off temporarily along with the 

condenser fans so the leak may be pinpointed using soap bubbles or an electronic leak 

detector. 

7. _______ Condenser Fan Blades and Motor Mounts: Check condition of condenser fan 

blades for cracking or tearing of the metal, especially at the point on the assembly where the 

fan blade is riveted to the hub. If cracking or tearing is present, disconnect the motor and 
replace the blade as soon as possible. Check motor mounts of each fan motor assembly for 

signs of deterioration and replace or repair immediately. 

8. _______ Sales Area: Walk through the sales area of the store with an electronic leak 

detector at its most sensitive setting. Probe the entire length of the discharge air stream of 

each refrigerated case. If a leak is detected, unload the case and check the evaporator coil, all 

valves, connections, and interconnecting piping until the leak is pinpointed. 

9. _______ Refrigerated Walk-Ins & Prep Rooms: Check each walk-in cooler, freezer, and 

refrigerated prep area in the store with an electronic leak detector at its most sensitive setting. 

If the leak detector indicates a leak, slowly reduce the sensitivity and progressively move to 

the leak location until found. 

10. _______ Underground Refrigerant Piping: Check sub-surface refrigeration access pits 

starting with the riser pits with an electronic leak detector at its most sensitive setting. If 

refrigerant is detected, reduce sensitivity to determine whether the leak is in that pit. If it is 

the leak is not in that pit, move to the next pit in the underground piping network. A drop in 

the leak detector reading may indicate that the leak is in the piping between the two pits. If it 

increases, continue checking each pit in the piping network until the leak is pinpointed in a 

pit connection or it is determined that the leak is in the interconnecting piping between two 

pits. If the leak is found to be in the interconnecting piping and the piping is not accessible, 

turn off each system that has lines passing though the pipe duct, one by one. This will 

increase the pressure in the suction lines and should trigger an increased leak rate reading on 

the electronic leak detector when the offending system is turned off. If this does not provide 

positive results, the next step is to pump down each system one by one. This will decrease 

the pressure in the liquid lines and should result in a decreased leak rate reading on the 

electronic leak detector when the offending system is turned pumped down. If the above 

steps do not yield positive results and there is a high degree of confidence that one of the 

systems in the pipe duct is leaking, it will be necessary to isolate each individual line and 

pressure test each to 300 psig using dry nitrogen for 24 hours. Once the leaking line is found, 

it will be necessary to replace the line or reroute the line overhead. 

11. _______ Overhead Refrigerant Piping: Check accessible overhead refrigeration lines by 

following the path of the lines using an electronic leak detector set at its most sensitive 

setting. If the lines are insulated, it may be necessary to probe under the insulation to pinpoint 

the leak. Be sure to properly reseal the insulation to preserve its integrity. 

 16 
17 

Appendix B. Monthly Refrigerant Receiver Level Chart 2011

Store #______________________ Rack #________________________ 

Refrigerant Receiver Level 

100% 

90% 80% 70% 60% 50% 40% 30% 20% 

10 % 

J-11 F-11 M-11 A-11 M-11 J-11 J-11 A-11 S-11 O-11 N-11 D-11 J-12 F-12 M-12 A-12 M-12 J-12 J-12 A-12