Yank,
We just went through the same situation, (we have the same A/C,) last week. We had over 95 degrees and probably humidity to match.
Thanks to help from fellow MOC posters, my personal solution proved to be to shut off A/C’s main power breaker, (and I probably would have pulled the A/C’s DC power fuse if I could only read the scribbles under the fuses,) take the cover off the air inlet at the ceiling A/C panel, undo and redo the connections to the control box in that inlet, and tighten all the wire nuts running from the control box.
To give it a “shotgun blast,” (that wasn’t apparently necessary for us,) you might also unscrew the thermostat from the wall, and unplug and re-plug the phone wire-looking connector behind it, too.
Then, turn power back on and try the A/C again.
Hearing from others, it’s highly possible that an A/C will only chill the air some 20 degrees below ambient temperature. Ours has been doing that since the above was done. But before that, for a few days, it had only been blowing whatever room air temperature was.
We have the remote thermostat, so if there’s a detected freeze-up in ours, the green A/C LED Indicator would be blinking. If you don’t have any indication that’d warn you of that, then running it at high speed, as mentioned, is the best solution to that.
As those Duo-Therm Quick Cool units leave the factory, they have no way of having coolant added to them. But they do have a three-year warranty, and an additional three years can be bought on their website for about $130. (If you haven’t registered your unit yet, it’d be a good time to get its serial number in their system, because you’ll need it written down to prove you’re covered, and a print-out of your registration will suffice.)
The Duo-Therm/Dometic website is at:
http://dometicusa.com/
I hope you won’t have to get it serviced. It may mean a trip to a shop.
Steve