My Home A/C Compressor Makes Noise on Startup

Warning

• A homeowner should not attempt to repair a compressor or open the unit to inspect for loose parts. He also should not attempt to remove the housing from the unit so he can stand back to watch and listen as the equipment starts. A visual inspection could help isolate the problem, but the risk of injury is too great. People who are inexperienced with HVAC repair could suffer electrical shock, cuts and other injuries while attempting to service the unit.

Possibilities

• Start-up noises may be traced to a loose bolt left in the appliance during installation. Rattling could be from the aluminum tubes containing refrigerant touching other parts in the unit. Simply removing the loose bolt or bending an aluminum tube could solve the problem. A broken spring or some other easily replaced part also may cause noise. Another factor is that some air conditioners become noisier overall as they age.

Diagnosis

• The problem is probably minor if the unit continues to cool the home effectively despite noises as it starts. Thumps and clunks coupled with the appliance's declining effectiveness, however, are clear indications that the problem may be serious.

Solution

• Having a reputable HVAC technician address the air conditioner's noise is the best way to solve the problem. In most U.S. states, HVAC technicians are licensed or certified by county or state officials. Reputable technicians show their license or permit willingly. Investigating an HVAC company before scheduling an appoint with one of its technicians is wise, as is getting references about HVAC companies from friends and neighbors and checking with the Better Business Bureau for possible complaints lodged against all companies considered for the job. The goal is to avoid an unethical company that may try to sell a new outside unit. Such an expense could total a few thousand dollars, depending on the current equipment.

Observation

• Asking about possibilities such as loose parts or bent tubing causing the noise lets an HVAC service technician know you did your homework. Stand outside while the technician examines the unit, and have the technician explain his findings.