Kung Fu Maintenance discusses the role and function of the filter drier in the air conditioner system.
OK. This particular part here is called a filter drier. When these are installed on traditional split system AC unit there is an arrow that points this way to show that the gas is running through this way and on the low side the gas is coming back through this way on the low side to the compressor there.
Filter Drier Function
What the filter drier does is it removes moisture from the system. Again moisture is bad for a system. If there is moisture in the line it will mix with the refrigerant and it will turn into an acid that will corrode the system. A new unit comes with a filter drier installed on the unit inside. You can see it there a little different style. This one has got three filter driers on it which is good. Keeping the moisture out of the system. Also any little particles that go through inside the system a lot of times will get caught in the filter drier. Which is good.
Anytime the system is opened for any reason you know replacing an evaporator coil, replacing a compressor, anything that opens the freon plumbing, you always want to replace the filter drier. Another important point on these filter driers. They absorb moisture which I told you already they absorb moisture. You don’t want to leave these points open. Even I have seen companies go and install a filter drier solder the end on and leave the end open while they are waiting for the crane to come and install the unit. If you can leave a cap on the other end after you’ve soldered your line so that the filter drier doesn’t just absorb moisture from the air. Because that is what it does. It has got a deal inside that absorbs the moisture from the air so we don’t want to absorb moisture from the air early on. We want it to absorb moisture from inside the system if there is any. You know we always want to again replace the filter drier anytime the system is opened and vacuum down the system to boil off any moisture that’s in the system.