R 454B Start Up/Commissioning Calculator / HVAC Calcs

Note: Verify airflow first, then let the system run ≥15 min or until pressures stabilize before using readings (R-454B stabilizes slower than R-410A).

Nameplate Tonnage (tons)

Target CFM per Ton

Airflow (CFM)

Delta T (°F)

Target Subcool (°F)

SC Tolerance (±°F)

Low-Side Pressure (psig)

High-Side Pressure (psig)

Suction Line Temp (°F)

Liquid Line Temp (°F)

Outdoor Ambient (°F)

Indoor Temp (°F)

Return RH (%) (optional)

Supply RH (%) (optional)

Target Airflow (CFM): —

Actual Airflow (CFM): —

CFM per nameplate ton: —

Subcooling (SC): —

Target SC: —

Superheat (SH): —

Evap Sat (°F): —

Cond Sat (°F): —

BTUh (sensible est): —

Estimated tons: —

CFM per estimated ton: —

CTOA (Cond Sat − OAT): —

Capacity Summary

Total

BTUs: —

BTU ton (total): —

CFM per total ton: —

Sensible

BTUs sensible est.: —

BTU ton sensible: —

CFM per sensible ton: —

CFM apportioned to sensible: —

Latent

BTUs latent est.: —

BTU ton latent: —

CFM per total ton: —

CFM apportioned to latent: —

Capacity Breakdown

Total BTUh (enthalpy): —

Latent BTUh: —

SHR (Sensible/Total): —

Suggestions

Enter values and press Calculate.

Airflow guidance is from ΔT. Charge guidance is by Subcooling to target. Superheat is safety/trim and can rise on heavier loads.