Bob M. wrote:

About 800 sq ft Cape Cod style house with forced warm air heat. Added 2-ton
York central A/C in 1989. Due to plenum shape, they put in a horizontal coil
rather than an A-shaped coil. Worked well once I blew insulation into the
house. Always felt very comfortable.

Replaced the furnace in 2000 with a Lennox gas unit, and they installed a
new Lennox A-shaped coil in the output plenum. Same 2-ton capacity. Same
York compressor unit. The system will cool the house down quite nicely, but
the humidity seems uncomfortably high at times, like over 50% even with the
temp down to 74F. On days when it's in the mid 90s the system will bring the
house down to the mid 70s and keep it there, cycling on and off as need be.
The condensation pump runs, but not nearly as often as it did with the old
setup. Cold air comes out of the ducts at about 58 degrees, so the system
seems adequate for "cooling" purposes.

The fan speed was factory set to the highest speed. I'm wondering: could
such a fast fan speed be literally blowing the air and moisture right off
the coolihg coil, and not giving it a chance to condense the moisture so it
drains out? I can lower the fan speed (I have 4 to choose from) but before I
get into that, I wanted to at least see if my theory made sense. I figure if
the air moves slower across the coil, the moisture will condense and drip
down and out. Never had this problem with the old horizontal coil.

Also, one of my upstairs rooms has its own 5000 BTU window A/C. When I run
that unit to cool the room down to 74, then leave it to go back into the
main floor, there's a noticeable increase in humidity and the room feels
clammy and uncomfortable. It's this comparison that's got me thinking the
central system isn't removing the humidity like it used to.

Any thoughts or suggestions? Is my analysis sound? I don't see any moisture
around the furnace, so I'm fairly sure the condensed water is going where
it's supposed to. When the thermostat shuts the system off, the condensate
pump usually comes on a few seconds later to pump the water out. That's why
I almost think it's saving it until the fan slows down or stops.

Thanks.
Bob M.
800 sq. feet and 2 tons seems like too much a/c for the building.......
if you dont want to turn the fan speed down then call out a tech and get
him to check it out and see whats wrong with it.. not the same guy who
put in the second unit for you... he will never find his own mistake...