Chiller tons from GPM and ΔT

Estimate chiller or coil load in tons from water flow and temperature difference.

What this means

Load in tons equals flow times temperature difference divided by 24 for water. Comparing it with the chiller's capacity at the same conditions helps spot low flow, fouling or a sensor issue. Small errors in ΔT have a big effect, so use accurate thermometers.

Formula used

  • Tons = GPM × ΔT ÷ 24 (water)
  • 1 ton = 12,000 Btu/h
  • Metric: kW = 4.19 × L/s × ΔT (K)

Related tools

Hydronic GPM, BTU and ΔT calculator · Cooling tower range and approach · 4 to 20 mA and 0 to 10 V signal scaling

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