[qcj]

This might be a stupid question, but how do you know when to change the air dryer? You might say when one starts to get water in the air tanks, but doesn't the 120 volts compressor also get water in the tanks? I pull the lanyard on my rear tank about every two weeks and drain the front tanks when under coach. I also check the small tank in front of the rear wheels. The rear tank with the lanyard usually has a small amount of water in it. Never have water in small tank, but have had small amount of water in the tanks in front, but only check maybe every 5 or 6 months. So when do I change the air dryer?