HVAC Tools PT Chart - Gauge

Gauge is a field toolkit for HVAC and refrigeration technicians: a pressure-temperature chart for 10 refrigerants, superheat and subcooling calculators, troubleshooting checklists and a service call log with PDF reports.

PT CHART
- R-410A and R-22 free; R-134a, R-407C, R-404A, R-32, R-454B, R-290, R-438A and R-422D with Pro
- Look up the saturation temperature for a pressure, or the pressure for a temperature
- Scroll the full table from -40°F, with safety notes for the A2L (R-32, R-454B) and A3 (R-290) refrigerants

CALCULATORS
- Superheat: suction pressure and suction line temperature give the saturation temperature and the superheat
- Subcooling: liquid line pressure and liquid line temperature
- Temperature split: return and supply air
- Ohm's Law: enter any two of volts, amps, ohms and watts
- Pro: airflow (required CFM from BTU/h or tons and the temperature split), duct sizing (round and rectangular sizes from CFM and air velocity), capacitor check (measured against rated µF) and voltage drop (copper wire by AWG, one-way length, amps and supply voltage)
Superheat, subcooling, temperature split, capacitor and voltage drop results are color-coded against typical ranges, with what to check next.

SERVICE CALL LOG
- Customer or address, complaint, system type, make and model
- Suction and liquid pressure, superheat, subcooling, suction line, liquid line, supply and return air temperatures, compressor amps
- Your diagnosis, the work performed, refrigerant type and amount, parts, notes, cost and time on the job
- Free: up to 10 service calls. Pro: unlimited calls, search, and a PDF service report with your name and certification that you can share with the customer

REFERENCE
- Step-by-step checklists: AC not cooling (free), furnace not heating and heat pump not heating (Pro)
- Typical ranges for superheat, subcooling, temperature split and compressor amps
- Refrigerant facts: GWP, A2L or A3 safety class and phase-down status
- System types, a copper wire ampacity table and an EPA 608 overview (certification types and key rules)

AI ADVISOR (PRO)
Describe a symptom or a set of readings and get a short written answer from an AI model. It sends only the message you type and needs an internet connection. AI answers can be wrong: check them against your own readings and the equipment manufacturer's data.

GOOD TO KNOW
- Gauge works in US units: °F, psig, CFM, inches, feet, AWG and pounds
- The PT chart, calculators, reference and service log work without a connection

GAUGE PRO
Free: the PT chart for R-410A and R-22, the superheat, subcooling, temperature split and Ohm's Law calculators, up to 10 service calls, the AC checklist and the reference tables.
Pro adds the other 8 refrigerants, the airflow, duct sizing, capacitor and voltage drop calculators, unlimited service calls with search and PDF reports, the furnace and heat pump checklists and the AI Advisor.

In the US, Gauge Pro is $4.99 a month or $39.99 a year (US prices; other countries see their own price in the app). Subscriptions renew automatically unless cancelled at least 24 hours before the end of the period. Manage them in your App Store account settings.

Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/