Quote:
Originally Posted by Discseven
TY for comments Will.
Goal was to bring system to near optimal meaning it would operate near its freeze threshold here in Miami---ambient moisture taken into consideration. Given an earlier test comparing temp in outlet of AC blower to vent with +1 dF delta at vent, and core temp test with temp dropping below 32 (albeit with no blower positioned), and driving v-temp at 32+ dF (speed 2 at around 85 outside ambient)... seems safe to say evap is operating at near optimal now.
Once upon a time I had noisy AC that blew near cabin temp air. Improvement is understatement. Perfect not necessary. My toying further with system is for fine tweaks and better understanding.
Will system hold 32+ dF at vent when ambient is 95 dF during mid summer? Will system now be able to flush car of internal heat reasonably fast after car's been parked in direct sun for 30 scorching minutes? We'll see when next summer comes.
Speaking of summer, subject of Targa roof insulation was raised. Don't recall where discussion went on that---insulated...or not(?) With extra roof on hand, am planning to take it apart to find out (and rebuild it.) From what I know, there's exterior skin, then burlap, then metal, then headliner. Seems there's better insulate than burlap to use. Be good for Targa roof expert to chime in.
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It seems to be common knowledge that the first thing to suspect is wrong in the case of evaporator freeze up is, would be. low refrigerant charge, I don't have much of an idea how that might be but will post my theory below(***). Perhaps CG can chime in and explain why that is using his "book of knowledge".
But it seems to me that focussing on vent temps as the major target leaves one fully open to the possibility, probability, of a low refrigerant charge. For myself, having not the knowlegde to be exact, I would shoot for the lowest vent temperatures but with a limit of suction side pressure indicating P&T temps above freezing. Plus a high enough engine RPM in order to ascertain that at FULL load and perfromance the low side suction would remain in the "safe", non-freezing range.
Up to now I Have always relied on the inexpensive kit gauge for topping off systems. But now that I have a gauge set I think the next time I will shoot for the greatest Delta "T", intaking outside airflow, windows open, and with elevated engine RPM.
I suspect that procedure will put me in the exact same charge "ballpark" as using the low side gauge reading as the charge level target... awaiting the next HOT day.... next June?
*** MY theory...With low refirgerant charge, and/or engine RPM so low that "apparent" charge is low, the core area near the inlet gets plenty of cooling, while the mid to end points on the core doesn't sode the evaporative process is limited to the narrow area near the inlet.
Meanwhile the system is working as hard as it might therefore the inlet area quickly drops below freezing, freezes up, and now that freeze "front" slowly progresses across the core until all airflow is blocked.