Trane charts say 10 to 15 degrees, depending on type of system.
Don't go by rules of thumb, you will get a brown thumb. Get Trane &
Carrier charging charts and check those conditions again!
Take this same day, assume the power has been off and it's mid
afternoon. So, the DB inside is up, but specific humidity hasn't
changed, @ 58.6 grains ( same as it was in the above )
DB 90, grains 58.6, WB = 66 ( RH 28 % ) ( OA still 95, as above )
66 * 3 = 198
Trane charts say 10 to 15 degrees depending on type of system. Of
course other manufacturers will have slightly different superheats.
Get their charging charts instead of using a rule of thunb. Tour thubm
might get smashed.
198 - 80 - 95 = 23
23 / 2 = 11.5 degrees of SH, under this max-load hot-startup extreme
condition ??? Sorry, no way. That's like half or less of the SH you
RA 72 DB / 50 RH , WB = 60 , OA 95 ( hot normal day )
(60 * 3) = 180
180 - 80 - 95 = 5
5 / 2 = 2.5 degree SH ???? I don't think so !!!!! You're gonna have
Trane chart says 2 degrees - go fight with Trane, it is their charging
chart. Under these conditions a small amount of liquid will not hurt,
the hot motor windings will evaporate it!
RA 72 DB / 80 RH , WB = 67 , OA 70 ( cool rainy day, lots of
building leakage )
( 67 * 3) = 201
201 - 80 - 70 = 51
51 / 2 = 25.5 SH ???? I don't think so !!!!! ( this implies running
a MUCH warmer coil, which is the WORST thing to do in this condition !
With an old Trane system, the superheat should be 29 degrees, with a
New 11 SEER Trane system, the superheat should be 22 degrees, with a
Trane packaged system, the superheat should be 28 degrees.
depending on conditions, the superheat will vary from zero degrees to
over 35 degrees. that is actual systems with piston metering device.
If you want constant superheat, install a TXV. That is why a TXV is
better than a piston. For efficiency, dehumidification, comfort!
RA 72 DB / 30 RH , WB = 54 , OA 80 ( warm dry day )
( 54 * 3) = 162
162 - 80 - 80 = 2
2 / 2 = 1 SH ???? I don't think so !!!!!
Old Trane & Packaged Trane = 4 degrees, 11 SEER Trane = zero degrees.
Stop thinking and start measuring.
Get a trane charging slide rule and a Carrier charging slide rule and
see what the equipment manufacturers say. Or start using TXV on all
your jobs and charge by subcooling. This is why I use a lot of Lennox!
They use TXVs on almost everything split.
That would be an equation of my own derivation, posted to this NG. It
was suggested to me that I copyright it. OTOH, anything published is
automatically protected under copyright law as "intellectual
property". If you publish this equation in any form you must send me
10 U.S. dollars via pay pal for each copy generated. Valid email in
Damn ! You just struck it rich !
That's now been replicated on at least 100,000 computers !!!
Someone owes you $ 1,000,000 !!!!
Do you take Paypal ?????
Oh, what the hell - here's another $ 1,000,000 for you !!!!!
How've you been?
Did you just...yes you DID post it again! Shit, I think I'll start
shopping for that private aisle and yacht!
Don't worry Paul, if you do a search you'll find that I granted
universal permission to use it as desired. Not too smart, but then you
set the worst example of marketing with your pjmtherm :)
As best I recall, didn't you offer the source code for free as well?
Must be more savants out there than I suspected :) You've apparently
tapped into the pockets of the PBS and/or Swaggart Minstries audiences.
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