WHEN GOOD ACCUMULATORS GO BAD

Q. Good day to you, Jim! After searching the web, and asking several different people (all who had different answers) I am still not sure... so here goes – Do all heat pumps have accumulators? How can you tell when it’s bad? And most of all, when replacing a compressor should you also replace the accumulator? Some say yes and some say no, so I’m turning to the expert. Thanks, Nelson W., Rhoads Co.

A. Nelson, good to hear from you. This is what I know – virtually all HP units have suction line accumulators. Their function is to store liquid refrigerant and prevent it from returning to the compressor. During the reverse cycle heating mode the amount of heat that is being transferred drops as a function of the outdoor temperature. With less heat being absorbed by the refrigerant in the outdoor coil it’s possible (and probable) that all of the refrigerant will not boil off to vapor. The accumulator’s job is to insure that only vapor refrigerant is returned to the compressor, and it does so by returning refrigerant from the top of the accumulator where the vapor collects.

If a refrigerant component failure occurs and debris is generated in the system this debris will eventually make its way back to the accumulator. Being heavier than the refrigerant it will drop to the bottom. The problem arises when this debris then blocks the small oil return hole at the bottom of the accumulator suction loop. This hole is there to control the return of system oil that collects with the liquid refrigerant during the heating cycle. If this hole gets blocked oil is not returned to the compressor and could result in a lubrication failure. This system debris is also why we recommend that the reversing valve and TXV be replaced when replacing a compressor. You may try to clean up these parts but it’s impossible to see if they are really clean plus the cost of cleaning may exceed replacing with new. Hope this helps!

Because he asked such a great question, we’ll be sending Nelson some great FREE merchandise. Would you like to receive some free merchandise for yourself? Then send in those questions, and if I use them here, we’ll send you your very ownT otaline treat!

Jim Flynn
Totaline Aftermarket Training Manager