You dont steam clean AC units..you chemically clean them, with a foaming
cleaner that gets into the coils and pushes out the crap in them.
But they seem to think that the cleaning process will take about a half
hour a unit.
For PTAC units, like you describe, that is prob about right to do it
properly.
The cleanings should be done with something other than Purple Stuff as
well...

You were right on almost all counts: Firstly they did what seems to have
been a good job for a fair price and most importantly for 24 year old units,
didnt try to sell me a new unit instead (they implied from an irregular
sound I COULD hear that a piston was going on one of the motors which might
need replacing on the next year or two: But on cleaning off the gunge from
the fans, - including some candle wax, - and reassembling the units, the
sound seems to have gone away even though they didn't oil anything).
Secondly the units appear to work properly now (except that I have no way of
telling how many BThUs they are putting out) but thirdly, they didnt do
anything to the coils except carefully brush and vacuum them and didn't seem
to intend to Nucalgon them (they didnt ask where they could properly clean
them, they just assumed they woudlnt need to). And all parts were included
in their price. These 12,500 BThU units have an eer of 8.1. How badly am I
doing on power use?