Can I measure a Negative Subcooling When Checking the Charge? (Quick Tip)
- Craig Migliacco
- Jun 29, 2020
- 1 min read
Updated: Mar 2
The answer is no because the refrigerant rejects heat in the condenser so the pressure and temperature of the refrigerant should lower. The refrigerant starts off in the condenser as a superheated vapor and after it rejects heat, it changes from a vapor state to saturated. After it rejects enough heat, the refrigerant changes to a subcooled liquid. In this picture, we see a saturated temperature of 105°F and a line temp of 93°F.
105 - 93 = 12°F of Subcooling
It is possible for the refrigerant to stay saturated instead of subcooling if the system is extremely low on refrigerant. A system that is very low on refrigerant may read 0-3 degrees of subcooling. Typically, there will be at least a small amount of subcooling measured. If the refrigerant is rejecting heat at the condenser, there is no way for the pressure or temperature of the refrigerant to increase as it makes its way through the condenser. It will either exit the condenser as saturated (saturated is liquid and vapor refrigerant in the same location) in a low refrigerant scenario or the refrigerant will be subcooled (subcooling is the lowering in temperature of the liquid refrigerant). If you are measuring negative subcooling, make sure your measurement locations are correct, otherwise you may want to recalibrate your tools!
Be sure to check out the full Subcooling Charging Method Article here!
Articles: https://www.acservicetech.com/articles Quizzes: https://www.acservicetech.com/quizzes Calculators: https://www.acservicetech.com/hvac-calculators Quick Tips: https://www.facebook.com/acservicetech Ebook, Book, Workbook, Quick Cards: https://www.acservicetech.com/ac-book Book, Workbook, & Cards: https://www.amazon.com/shop/acservicetech Tool Lists: https://www.amazon.com/shop/acservicetech
.png)
Felicitaciones por mantener estándares tan altos de seguridad y atención al cliente. Es inspirador ver organizaciones que priorizan el bienestar de sus visitantes mediante acciones concretas. La transparencia siempre aporta valor, incluso en sectores distintos como lotería nacional, donde la confianza también es fundamental.
Excellent technical explanation. HVAC topics can sometimes be difficult to understand, but this article broke down the concept of negative subcooling in a very practical and accessible way. The troubleshooting insights and real-world context were particularly valuable. The clarity of the explanation reminded me of a discussion I recently encountered through https://gocollectiv.com/, where professionals were sharing different perspectives on system diagnostics. Content like this is extremely helpful for technicians looking to strengthen their understanding and avoid common mistakes.
The article I saw was interesting because of the presentation.
built-to-suit data center
Very clear explanation of subcooling and why negative readings usually mean measurement errors. I’ve made similar mistakes during HVAC practice, so this helped me a lot. It also reminds me of how five nights at epstein's fans analyze small details carefully.
This is an excellent explanation of why negative subcooling is impossible during a charge! It really clarifies the refrigerant's journey through the condenser. The "Quick Tip" format is fantastic for getting straight to the point. For more insightful articles like this, I highly recommend checking out the content at AI Clothes Changer – they also have some truly innovative features!