Radiator Installation Manual

Flow rates for a Pensotti steel panel radiator system are based on the calculated heat loss of each
heating zone. Using the calculated heat loss, determine the Btu load of each individual zone. The
following formula will be used to calculate the flow rate from the Btu load of the individual zones.
Flow Rate (GPM) = Heat Loss (Btu/h) / 499.8 x Delta T (F)*
Delta T is the temperature difference between the supply and return of the radiators in each zone.
The following table provides several divisors for the above formula to make calculations quicker and
easier.
Delta T (F)
Divisor
10
5,000
15
7,500
20
10,000
25
12,500
30
15,000
35
17,500
40
20,000
45
22,500
50
25,000
Flow Rate (GPM) = Heat Loss (Btu/h) / Divisor (above chart)
Example 1:
Calculated Heat Loss of 23,500 Btu/h
20 Degree Delta T
Flow Rate (GPM) = 23,500 / 20 = 10,000 (above chart)
GPM = 23,500 / 10,000
GPM = 2.35
Example 3:
Calculated heat Loss of 31,250 Btu/h
35 Degree Delta T
GPM = 31,250 / 17,500
GPM = 1.786
FLOW RATE