RefrigCharge

R-410A subcool 7°F vs target 10°F - undercharged or low airflow? Diagnoses subcool, superheat, and charge advice for 5 refrigerants. $4.99 one-time, no login.

Built for HVAC service techs and install crews who need subcool / superheat diagnosis on the roof - not a dashboard you log into.

WHAT IT DOES Computes measured subcooling and superheat from your gauge readings, compares them against per-refrigerant target windows, and tells you whether the system is undercharged, overcharged, or showing airflow issues. Charge adjustment advice differs for TXV vs. piston / cap-tube metering, matching the field workflow.

REFRIGERANTS SUPPORTED

• R-410A
• R-22
• R-134a
• R-404A
• R-407C

INPUTS

• Refrigerant type (picker)
• Metering device (TXV or Piston / Cap Tube)
• Liquid line temperature
• Condensing saturation temperature
• Suction line temperature
• Evaporating saturation temperature
• °F or °C toggle

RETURNS

• Measured subcooling vs. target (color-coded: green within ±3°F, red outside)
• Measured superheat vs. target (color-coded)
• Diagnosis: undercharged, overcharged, normal, or airflow issue
• Charge adjustment advice: ADD, REMOVE, or CORRECT
• Adjustment basis: subcool for TXV, superheat for piston

WHY THIS APP, NOT THE FREE ONES

• Math is shown - measured minus target, with the per-refrigerant windows visible.
• Status at a glance - color-coded so you do not have to do mental arithmetic on the ladder.
• Works offline - RF-shielded basements, attics, and roofs. Always available.
• No login. No ads. No telemetry. No subscription.

PRICING $4.99. Pay once, own it. Lifetime access on iPhone, iPad, and Mac via Family Sharing.

NOT A SUBSTITUTE FOR The manufacturer's charging procedure for your specific equipment. The equipment data plate's nameplate charge. Calibrated gauge sets. This app gives you a directional read - verify against the OEM service manual before adjusting.