InspectAPedia ^®

Air Conditioning & Heat Pump Refrigerant Leak Repair Procedures AirCondAPedia © Enter your search terms Submit search form   Search This Website - InspectAPedia.com How to diagnose & repair refrigerant leaks in the air conditioning or heat pump system Leak repair tips for the HVAC cooling coil or evaporator coil

This article discusses how to repair refrigerant leaks in air conditioning and cooling systems, using as an example, repairing a leaky or damaged air conditioning the cooling coil (evaporator coil) in the air conditioning air handler unit. Our photo at page top shows the cooling coil in the attic air handler component of a central air conditioning system.

If your air conditioning system has lost its cooling capacity or won't start see REPAIR GUIDE for AIR CONDITIONERS. See How to determine the cooling capacity of air conditioning equipment if the system seems to be working but is inadequate to cool your building. Contact us to suggest text changes and additions and, if you wish, to receive online listing and credit for that contribution. © Copyright 2008 Daniel Friedman, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use links at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

How To Repair HVAC Refrigerant Leaks

First we need an accurate diagnosis of the problem. If your air conditioning or heat pump system has lost cooling (or heating) capacity, there can be various causes besides loss of the refrigerant in the system.

1. First, see LOST COOLING CAPACITY to diagnose just why the system is not working.
2. If you know that the refrigerant level is low or zero, don't just re-charge the system. Find and fix the refrigerant leak. See REFRIGERANT LEAK DETECTION. While it's quick (and cheap) to just add refrigerant to a system, we were taught at HVAC school to scorn earning a living by developing a refrigerant gas delivery route.
   
   An air conditioning or heat pump system is normally completely sealed and should never "use" refrigerant. Refrigerant gases are not a substance which is "consumed" in an HVAC system. In an emergency, such as at a commercial establishment needing time to move frozen food, one might just add refrigerant, but the proper repair is to find and fix the refrigerant leak.
3. If the refrigerant gas leak is in a valve or access port, such as the service ports to which the HVAC technician connects her gauge set, the valves there may be able to be cleaned and salvaged, or the valves may need to be replaced.
   
   Replacing a refrigerant gas service port valve is a soldering job similar to what we describe just below. In our AC repair career we never had to replace one of these valves but we did have to install them on some systems where they were not already in place.
   
   Our photo at left shows refrigerant gauge access ports on a compressor/condenser unit.
4. If the refrigerant gas leak is in the air conditioning or heat pump copper tubing a repair should be easy - the damaged line is re-soldered using high silver content solder and a high temperature torch. (We used MAPP gas for silver soldering of copper fittings, some techs use Acetylene or other gases).
   
   A damaged section of refrigerant line may need to be cut out and replaced. The repair is about the same regardless of whether the leak was in the larger diameter suction line or the smaller diameter high pressure line.
5. If the refrigerant gas leak is in the condensing coil or in the evaporator coil, repair might be possible, but we're less optimistic that repair is possible, but it might be, as we explain just below.

Guide to Repairs of an Air Conditioning or Heat Pump Evaporator Coil or Condensing Coil

1. Review the coil inspection, diagnosis, and repair tips at COOLING COIL or EVAPORATOR COIL. We find that the terms "cooling coil" and "evaporator coil" are used as synonyms in most cases. Sketch at left courtesy of Carson Dunlop.
   
   Even if the cooling or condensing coil has a repairable leak, if the coil is badly damaged such as having all crushed fins, it may be best to replace it.
   
   Damaged cooling / evaporator coil fins over more than 10% of the coil surface, blocking air flow may be a reason to replace the coil.
2. If the cooling coil or condensing coil is in good physical condition but it's dirty, it needs to be cleaned before it can be repaired. Spray-on coil cleaners are used by lots of HVAC technicians.
   
   If the coil is dirty with moldy dust and debris and especially if the building is occupied by people at extra health risk, we don't like to see a coil cleaned by blowing it off with compressed air, as you're simply sending all of this moldy junk into the building. See DIRTY COOLING COIL and see Mold Growth in Air Handlers. You may also want to check out Leaks, Rodents In Air Handlers.
3. Next check the cooling coil or evaporator coil for visual evidence of refrigerant leaks. Visual evidence of a refrigerant leak on a coil may include stains from refrigerant oil left at the point of leakage. See REFRIGERANT LEAK DETECTION.
4. When the one or more places where the cooling coil or evaporator coil is leaking refrigerant gas have been found, it's time to decide if we can perform a solder repair of if the coil has to be replaced. We offer some suggestions just below at Guide to Evaluating Evaporator Coil or Condensing Coil Refrigerant Leaks
   

Guide to Evaluating Evaporator Coil or Condensing Coil Refrigerant Leaks and Deciding to Repair or Replace a Coil

• If the refrigerant leak is in copper tubing anywhere in the cooling or heat pump system that is not too close to an evaporator coil or condensing coil, it should be possible to solder a repair, then evacuate and recharge the cooling system.
• If the refrigerant leak is in thin copper tubing that just melts when you try to solder it, as suggested by one of our readers, your technician may fabricate a copper sleeve that slips over the damaged tubing and is then soldered in place.
• If the refrigerant leak is in copper tubing in or close to the cooling coil (or in a condensing coil) a solder repair is hard to complete because the heat of the soldering process tends to de-solder other nearby connections. It might be possible if the technician is very expert and if s/he knows how to keep nearby surfaces cooled (we've used a wet rag).
• If the refrigerant leak is in an aluminum part, soldering aluminum is more tricky and may not be feasible. Ordinary procedures using a torch, for example, just melt the aluminum. Expert welders use inert gas welding methods.
• If the refrigerant leak is due to severe corrosion anywhere in an HVAC system we're not optimistic that a solder repair is possible. The conditions that caused a corrosion-related leak are likely to have thinned and weakened other parts. The cost of an attempted repair may be wasted.

Replacement of the cooling coil (or condensing coil) is more often going to be recommended by your HVAC technician because of these difficulties.

Recharging the HVAC System after Refrigerant Leak Repair

In case you didn't realize it, in order to solder a repair in an air conditioner or heat pump piping, tubing, evaporator coil/cooling coil, or condensing coil, it will first be necessary to remove all of the refrigerant from the system.

Installing a Dryer / Filter Unit on the Air Conditioning or Heat Pump Refrigerant Line

Use links just below or at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

AIR CONDITIONING SYSTEMS
AIR CONDITIONER BTU CHART
AIR CONDITIONER COMPONENT PARTS
AIR CONDITIONER TYPES, ENERGY SOURCES
AIR CONDITIONER NOT WORKING
AIR FILTERS for HVAC SYSTEMS
AIR HANDLER UNIT
  ADDING A/C: RETROFIT SIZING
  BLOWER LEAKS, RUST & MOLD
  COOLING COIL DEFECTS
  DIRTY A/C BLOWERS
BACKUP HEAT for HEAT PUMPS
CLEANING & Legionella BACTERIA
COMPRESSOR & CONDENSING COIL
CONDENSATE HANDLING
CONTROLS & SWITCHES
COOL OFF HEAT Thermostat Switch
COOLING CAPACITY, RATED
COOLING COIL or EVAPORATOR COIL
  DAMAGED COOLING COIL
  DIRTY COOLING COIL
  DIRTY COIL CLEANING PROCEDURES
  FROST BUILD-UP
DATA TAGS on AIR CONDITIONERS
DUCT SYSTEMS
DUCTS - Asbestos
DUCT SYSTEM DEFECTS
DUCT INSULATION, Asbestos Paper
DUCTS, Asbestos Transite Pipe
DUST FROM HVAC?
FAN AUTO ON Thermostat Switch
INSPECTION CHECKLIST - OUTDOOR UNIT
INSPECTION LIMITATIONS
LOST COOLING CAPACITY
  What to check first
  Compressor failure diagnosis
  Duct & Air Handler diagnosis
MOTOR OVERLOAD RESET SWITCH
OPERATING COST
OPERATING DEFECTS
OPERATING TEMPERATURES
  Air Conditioning System Temperatures
  Instruments Used to Measure A/C Temperatures
  Procedures for Making Temperature Measurements
REPAIR GUIDE for AIR CONDITIONERS
REPAIR & DIAGNOSTIC FAQs for A/C
REFRIGERANTS
  REFRIGERANT LEAK DETECTION
  REFRIGERANT LEAK REPAIR
SEER RATINGS & OTHER DEFINITIONS
SYSTEM OPERATION
THERMOSTATS
THERMOSTATIC EXPANSION VALVES
CRITICAL DEFECTS
Air Conditioning "How To" Books
More Information
FURNACES WARM AIR HEATING SYSTEMS

Technical Reviewers & References

• Daniel Friedman - principal author/editor of the InspectAPedia ^TM Website
• Thanks to to Guy Benfante, Chesapeake, VA 8/26/07 for the photograph of an ice-blocked air conditioning system evaporator coil and for his suggestion that we provide an air conditioning system troubleshooting FAQ.
• Thanks to Mark Cramer, Tampa Florida, for assistance in technical review of the "Critical Defects" section and for the photograph of the deteriorating gray Owens Corning flex duct in a hot attic. Mr. Cramer is a Florida home inspector and home inspection educator.
• Thanks to Alan Carson and Bob Dunlop, Carson Dunlop, Associates, Toronto, for permission to use illustrations from their publication, The Illustrated Home which illustrates construction details and building components. Carson Dunlop provides home inspection education, publications, report writing materials, and home inspection services. Alan Carson is a past president of ASHI, the American Society of Home Inspectors.
• Thanks to Alan Carson, Carson Dunlop, Associates, Toronto, for technical critique and for providing a copy of Carson Dunlop Weldon & Associates Technical Reference Guide to manufacturer's model and serial number information for heating and cooling equipment ($69.00 U.S.).
• Thanks to reader Don Jackson for HVAC refrigerant leak soldering repair tips (Aug-Sept 2008).
• Wikipedia provided background information about the definition of HEPA and airborne particle interception.

More Information on Building Diagnostic Inspections and Repairs

InspectAPedia® Home & Site Map - Building & Environmental Inspection, Testing, Diagnosis, Repair, & Problem Prevention Advice: In-depth research & advice on diagnosing, testing, correcting, & preventing building defects & indoor environmental hazards. Unbiased information, no conflicts of interest.

The Mold Information Center: What to Do About Mold in Buildings, When and How to Inspect for Mold, Clean Up Mold, or Avoid Mold Problems

Use this simple, economical mold test kit by following our instructions on how to collect and mail mold samples to our lab

Environmental Inspection, Testing, & Diagnosis On-Site IAQ, Gas, Air Testing, Mold Investigation, Sick Building Diagnosis, Lab Services, & Remediation Plan Preparation - indoor air quality testing, problem source determination, supporting lab work, written remediation plan addressing removal of environmental and other hazards and prevention of their recurrence.

Building Inspection, Problem Diagnosis, Forensic Investigation & Testing, Repair Consulting

Contact Daniel Friedman for website content suggestions or for fee-paid consulting

	Enter your search termsSubmit search form
	Search InspectAPedia.com