I've got an inexpensive Harbor Freight refrigeration style air dryer. It has worked pretty well since I got it. The day before yesterday I had an airline blow out (rubber whip) and the compressor was running continuously until I unplugged the whip. The air dryer had shut down. Thermal switch tripped. I wound up with moisture throughout all my lines. I was in the shop office working on a design and I don't know how long the unit was shut down due to the trip.
I didn't run the shop yesterday as we were surrounded by thunder storms most of the day, and I can not afford to lose a machine due to a lightning strike, or lose a job due to a power loss.
This morning I've been in the process of trying to clear all the moist air out and run dry air in, but the dryer does not seem to be working. I've got a filter separator on both the input and the output of the dryer. The fan has kicked on and the compressor is running, but I still keep getting moisture in the down stream separator. The auto drain is working, and there is no more than a little moisture accumulating in the auto drain float bowl.
I'm at a loss unless its just no longer working. The only other thing I can think of is that the humidity has been really high for the last couple days. (High for Yuma anyway.) On-line weather says we are sitting around 46%. This is our "monsoon" season. The rest of the year we tend to run 8-15%. Maybe this cheap dryer just isn't up to handling that much humidity.
Run out and buy an Ingersol Rand air dryer is not an option for today. Maybe next time I get a big job.
Throw away desiccant filters on the individual machines might be ok, but they use continuous air on the spindle nose air seals. I suspect I'd be replacing them every day if not sooner.