Daisy,
I chose the Carrier for a lot of reasons. One; is they are a good maker
still...I hope, Two; is I have Coleman, DuoTherm and Dometic and I've a few
model issues I don't like, such as DuoTherm's delay controller which I just
hate, Three; I never had a Carrier which was the late-comer to roof air, and
Four; Carrier is the only one with powered oscillating fore and aft vents
and a center cold air down-draft vent that they call something like "Blast
of Air". I really like that, Five; The shroud cover is really made well. The
unit also can come ducted and remote controlled. It had the best low pricing
of all of them.
Pluses: All the newer ones are scroll compressors with high EER's. All are
lighter weight and operate just above 10 amps instead of the 20 amps. All
have a LRA of about 20 amps instead of 40 amps. All have a lower profile.
All will perform almost the duties of what two usually were needed. All will
freeze you out. All work so well you don't need to spend the money for the
15000 BTU models, the smaller work great. On my motor coaches the generators
4 kw and up can easily pull the load of two on simultaneous start and it
required a 7 kw generator to pull two of the old piston type. The generators
don't labor and struggle as before.
Downside: Coleman still can't make a good shroud that will last and last.
None have full auto-shut down. All are cheapy exposed Styrofoam air handler
construction on the cheapest made structure and mount points which makes
handling without damaging during installation difficult. None have three
levels fan speed selection like all the old ones. I miss that. All have
better ceiling fixtures now.
Your old Armstrong probably would get quieter with new compressor rubber
feet and a tear-down cleaning of the squirrel cage fan. The rubber feet are
generic and real inexpensive. New feet are simple to install. That's a lot
of work to get the fan out and clean that blower but if removed and run thru
the dishwasher it not only will clean the scuppers and make it balanced
again, it will blow a lot more air. If you get help for taking it apart to
clean the blower you might as well clean the condenser (hot air fan) fan
thru the dishwasher while your at it. Dirt on fans makes them vibrate and
significantly reduces the air volume they produce. Good filters are a must
do to prevent squirrel cage dirt build up. There is nothing you can do for
the condenser fan, but it doesn't get that dirty.
Off season and seldom use allows dirt dabbers which just love a fan. One big
old dirt dabber nest on a fan will make a lot of racket. It never totally
breaks off. Make the dabbers really angry when you turn it on.
-Eddie-
Houston, TX