FORMULAS & FACTS
GPH (Gas) =
(BTU/H Input X % Eff.) divided by
(temp. rise x 8.25)
GPH (Electric) =
(KW x 3413) divided by
(temp. rise x 8.25) or (KW x 414)
divided by (temp rise.)
KW required =
(GPH X 8.25 X temp. rise)
divided by 3413 or
(GPH x Temp. rise) divided by 414
1KW =
3413 BTH = 4.1 GPH @ 100°temp.
rise or 4.6 GPH @ 80°temp. rise
Meters =Inches x .0254
Centimeters =Inches X 2.54
mm (millimeters) = Inches x 25.4
One boiler horsepower (BHP)=
33,475 BTU
One cubic foot of Natural Gas
contains about 1000 BTU of heat.
One “therm” is equal to
100,000 BTU (100 CU. FT.)
One cubic foot of Propane Gas
contains about 2500 BTU of heat.
One gallonof Propane gas contains
about 91,250 BTU of heat.
One poundof Propane gas contains
about21,600 BTU of heat.
One pound of gas pressure
is equal to 27.7 inches water
column pressure
Inches of Water Column
x.036091 = PSI
Inches of Water Column
x.073483 = Inches of
Mercury(Hg.)
One pound per sq. in.
=16oz per sq. in.
Water expands
approximately 2% in volume
for a 100°Ftemperaturerise
(from 40°F to 140°F)
Water confined
to a storage tank or piping
system, when subjected
to a temperaturerise of 10°F
(increasing from 75°to 85°),
increases pressure from
50 psi to 250 psi.
TUBING SIZE 1⁄23⁄411
1⁄223
g/ft type L .012 .025 .044 0.92 .161 .354
Water capacity of copper tubing per foot
TC-092
FORMULAS & FACTS