HVAC Procedure and Performance Guide

Clean system after burnout

Training for this procedure can be found in these courses:

                         131 – Oil Heat l  and  161 – Boilers l


Refrigeration system must be clean after compressor burnout.  Special manufacturer’s instructions must be adhered to in cleaning system.  All carbon deposits, moisture and acid must be cleaned from system.  Compressor must be replaced.  System must be operated for prescribed length of time to complete cleaning.  Applicable safety procedures must be followed.  EPA regulations regarding discharge of refrigerants to atmosphere must be satisfied.


  1. Review job order and manufacturer’s specifications.
  2. Determine type, voltage requirements and capacity for compressor.
  3. Collect tools, equipment and materials.
  4. Put on safety and protective equipment and apparel.
  5. Perform electrical tests on suspect compressor and determine if burnout has actually occurred.
  6. Perform acid test and inspect compressor oil to determine severity of burnout.
  7. Classify burnout as MILD or SEVERE.
  8. Consult EPA regulations on discharge of refrigerants to atmosphere before performing the following procedures.  Recover refrigerant if required by regulations.
  9. Perform clean-up:

a. If MILD burnout (oil shows no acidity):

1)  Replace burned-out compressor.

2) Install an oversized filter-dryer in liquid line.

3) Evacuate system and recharge according to manufacturer’s specifications.

4) Place system in operation and check performance according to manufacturer’s recommendations.

5) Leave system in required operating status.

b. If SEVERE burnout (acidic oil with carbon deposits):

1)  Replace burned-out compressor.

2) Install suction line filter-dryer ahead of compressor with isolation and access valves on each side.

3) Install oversized filter-dryer in liquid line with isolation valves and install liquid line moisture indicator.

4) Disassemble and clean or replace expansion valves, four-way valves, etc. according to manufacturer’s requirements.

5) Evacuate system using triple evacuation method.

6) Recharge system through access valve on suction line filter-dryer.

7) Place system in operation and measure pressure drop across suction line filter-dryer for first hour.

8) If pressure drop exceeds manufacturer’s specifications, shut system down and replace filter-dryer.

9) Repeat Steps b7 and b8 as many times as necessary.

10) Take follow-up sample after 24 hrs. of operation.

11) If oil is acidic or dirty, shut system down, discharge refrigerant, replace both suction line and liquid line filter-dryers and evacuate and recharge system.

12) Allow system to operate for 2 weeks and retest oil.

13) Repeat Step b10 as required for further cleaning.

10. Leave equipment in required operating status.

11. Remove safety and protective equipment and apparel.

12. Gather tools, equipment and leftover materials and leave work site clean.