Superheat & Subcooling Calculator — HVAC Charging

What should superheat be on a fixed-orifice system?

Target superheat on a fixed-orifice (piston) system depends on indoor wet-bulb and outdoor dry-bulb temperature — you read it from the manufacturer’s target-superheat chart rather than a single number. In mild conditions it can be 20°F or more; in hot, humid conditions it can drop near 5–10°F. Charge to the chart value at the current conditions.

Related questions

• What is a good subcooling number?
• Do I charge by superheat or subcooling?