First, I have 'never' seen 'SC data' on the equipment 'nameplate'.
On the technical 'data sheet'? YES, but then again... why would someone look for a basic measurement (such as SC) on an air conditioner?
Did you not get your answer in your other thread?
And, if you are just testing me, you better get a tougher question!
Im asking you because I dont know. What I got from the other post was 10 is the lowest. So whats the answer?
Here is more on your question...Because I'm in a generous mood. LOL
"Thermostatic Expansion valves will work perfectly at a full liquid supply to it at very low pressures, but capillary tubes are dependent not only on a full liquid flow but also the pressure of that flowing refrigerant. So the subcooling may go quite a bit higher on capillary or flow-restriction devices than it will on the TXV.
The amount of subcooling for TXV systems may range between 10 and 15 deg. F. and this is perfect for the successful flow of liquid at the TXV and it should function perfectly unless you have extra long refrigerant lines leading to the evaporator or it is extremely high in elevation above the condenser. Every fully charged system will have subcooling.
Capillary tube systems may have 15 to 30 degrees subcooling when they are working right. Remember they are also dependent on the pressure of the refrigerant to "force" the liquid through a restrictor. Determine the correct refrigerant charge on them by relying more on the SuperHeat once you are in-range with the SubCooling."
Thanks, I understand you should keep subcooling between 10 to 15. But what has me questioning is, I know Ive seen carrier units with required subcooling right on the nameplate. I belieave Ive seen some call for as low as 9 and some as high as 13. I guess I should of asked why one would call for 9 and another for 13. What determines the required subcooling?
NOw that you mention a 4 ton and a 5 ton together, did you adjust for the difference in coil size?
When installing York, which is by weight only, they give adjustments for orifice AND the charge change due to using other than spec coil.
So if you used an a/h with a condensor, the matching a/h might be 69 orifice and 0 charge adjustment, but a cased coil on same cond would be a 70 orifice and 5 oz charge adjust PLUS the lineset adjustment.
I'm still trying to find this factor on Trane's literature.
And an extra thrown in, York has in their binder that stays in office, a sheet that shows adjusting the orifice based on lineset length and rise/fall. I've seen the sam chart for Bryant,too.
Of course, you could ask your factory rep about this and see if they have more tech literature that would shed some light .
questions asked, answers received, ignorance abated