I was wondering if anyone knows the basis for the 80% ROT, when upgrading an R12 refrigerent system to use R134?
What property necessitates the use of less charge?
JW
- posted
17 years ago
Refrigerent substitution
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- posted
17 years ago
IIRC, R134A is both somewhat less dense than R-12, and it boils at a higher temperature per a certain pressure.
In a CCOT system, that would normally only require reducing the size of the oriface tube, and _maybe_ reducing the charge so as not to cause a hydrostatic block on the liquid side. In a thermostatic expansion valve system, you might not have to do anything.
In a capillary tube system, it would require reducing the charge both to avoid hydro-lock, and to establish a lower pressure on the evaporator side.
LLoyd