Newell has told me if plugged in ,or generator is running, run the merge, or in my case emergency start switch. If you are storing your coach and you are on auto level the 12 v will not supply air to the leveling system. Newell told me to use a shop charger when storing if at all possible and then neither compressor on the coach is used.
I think using a stand alone compressor has some merit. One, they are easily obtainable at any Lowes or HD. Two, they are a lot cheaper than either the 110 or 12v replacements. Three, and most important for me, is water containment. My aux does not currently have a separator. I go back and forth on whether to mount one. In my limited experience, all separators eventually leak. If using a standard pancake style compressor, than you automatically have a tank that is very easy to drain.
Just overthinkin on a cold and snowy Black Friday morning, cause homeboy is NOT getting out in that madness.
When in storage for months at a time, I plug in the large shop compressor which has a water separator, set the output at 100 lbs, turn off both coach compressors to save them, and I am plugged into 50 amps. I leave the merge switch off since I have an Echo-charger. I am undecided whether to leave the coach in level or travel mode with the bags inflated.
I am with you Richard, not sure that a water separator is that valuable since the air needs to cool off before the Water will come out of the compressed air, this makes an external air compressor much more desirable in my mind.
When I was in the industry I used to make water traps by having larger pipe installed vertically in the air line run. The pipe would have a Petcock to allow drainage, surprising how much moisture can get collected. When moisture could become a real issue then refrigerated and/or desiccant dryers were used but then lubrication would become a problem.
Chester, I try to drive my coach at least once a month for about 25 miles, when I don't have a trip planned. I leave my coach air bags in travel mode and it hardly goes down during that time. My storage floor is level.
I cut on the merge switch for a couple of days about every two weeks. This seems to work for me. I also check the water in the batteries once a month.
We are merged whenever plugged in or parked with generator running and coach engine off for overnite. Unmerged if generator is not running for overnite or we are not plugged in to shore power. Always merged in storage or park while plugged in to shore power.
Learned a good deal from all these posts. I'm going to post in a new thread about slides in or out while stored.