A/C Drier Question

[John Allingham]

When I see a drier on an older central A/C system, does that mean the system has been worked on or do some units have driers from day one?

[Blaine Wiley]

Could be either.

[David A. Andersen]

As a matter of good practice all HVAC equipment should have a dryer. Package units will normally have dryers installed from the factory (some are very small and are part of the copper piping system).

These dryers should be changed whenever the refrigeration system has been opened. It is a policy for dryers to be installed after compressor failure. There are two types of dryers, one that goes on the small line in one a goes on the large line. The one on the large line (the suction line dryer) is designed to clean up a contaminated system after a compressor burnout. There are two refrigeration access valves on these dryers to determine a pressure drop across the device which would indicate that it should be removed/replaced. This test is restricted to EPA certified mechanical contractors. If you should happen to see frosting or ice on the unit side of the piping adjacent to the dryer and not on the other, this is an indication of a pressure drop as a result of a clogged dryer. Further evaluate by mechanical contractor.

[sparksnmore]

Normally if you see a suction line filter-drier it means someone suspected a burned out compressor might have contaminated the system with acid.

All A/C systems should have a liquid line filter-drier but many times they are hidden inside the high side unit.

{EDIT} oops I see Dave already ssid that and I skipped over it.

[John Allingham]

Thanks guys.