Originally Posted by 09 harley
Two additional points. Depending on how long your trip is you may have enough water to over flow the cup when you defrost. There may be a small vent plug in the end of the hose, keep it clean so water doesn't back up into fridge.
I had a four-door Norcold 1200 for ten years, with 7 years of that full time, and never saw the cup even close to overflowing. Even if it did there was a drain pan below it with a drain out the bottom of the coach. I did clean the dirt out of the plug a couple of times a year.