udarrell wrote:

RP wrote:



udarrell wrote:

TURTLE wrote:

"jessica" wrote in message
oups.com...


We have decided to go with a 14 seer heat pump with back up propane.
Now the question is what size? Different contractors have said
anywhere from 3 ton to 4 ton. Only one contractor actually did a
Manual J. He determinded we need 41,000 BTU for cooling and 75,000
BTU
for heating. He recommends we go wtih a 4 ton unit. There are actual
BTU's and sensible BTU's, and given our area, we should size to 4 ton
to match the "sensible BTU's" Does this make sense? This contractor
has come with very good reviews. We just want to oversize the unit.

I live in southern maryland about 35 miles south of D.C. We have very
hot and humid summers.

Thank you!

Jessica





This is Turtle.

Go with the contractor that did the Manual J and go along with the 4
ton 14 seer / propane back up because some contractor have dought
about the Manual J reading and will up a 1/2 ton in there
recommendations to remove errors.

i just can't picture Southern Maryland being a hot area of the
country but could see a humid area.

TURTLE


Turtle, we know that they should size for the latent humidity load as
well as the sensible load.
That is especially true in a high humidity area like he lives in.
The latent load is a major critical factor toward efficiently
achieving the human comfort zone.

When the humidity is high the latent load will take a lot of BTUs
away from the sensible capacity of the evaporator; which will also
provide more needed run-time.
However, they should be careful not to oversize, --because it takes
adequate run-time to get the humidity percentage down.

If they have the blower speeds to do it,-- they could use a relay
operated by a dehumidistat to go to 350-cfm per ton airflow for a
colder coil, when needed until the dehumidistat is satisfied.
- udarrell


If it's a piston metered coil, then how are you going to charge the
system? In low or high speed?
What happens to superheat when the blower speed changes?
hvacrmedic

That is what the rule makers' should have eliminated instead of the
10-seer.
For those high humidity conditions we ought to pump the system down and
tear out the flow-rator-****er crappers and replace them with TXVs.

Well, we know what can happen with low temperature heatloads combined
with low CFM; freeze-ups and slugged compressors.
Some hot blooded babes that get all sweaty in bed doing it, run the
RM-TH at 68 or lower at night when it's real cool outside.

Of course, that provides us with more work. I always told her or him to
buy a big floor fan and run it on high if they were going to be doing it
most of the night. Some laughed and some got ****ed off but then usually
started laughing. One fine lady just rolled her big blue eyes blushed
then looked away. (That's all I'm saying here.)
- udarrell

I'm not touching that

hvacrmedic