OM-07174
SUPER T SERIES
PAGE B - 4
INSTALLATION
FUEL TANK (LPG ONLY)
The amount of LPG fuel required for the engine is
measured in BTU (British Thermal Unit) per hour.
This unit requires 1,142,038 BTU/hr of LPG fuel
at 10 inches of water column.
The amount of fuel which must be stored at the in
stallation will be determined by the length of time
the engine must operate before refueling is neces
sary. Engine operating time is predicted on system
characteristics such as flow rates, pump capacity,
anticipated number and duration of power failures
in a given time period, programmed engine exer
cise periods, etc.
On LPG fuel systems, fuel consumption is mea
sured in British Thermal Units per Hour (BTU/HR).
This rate of consumption will vary according to en
gine speed and load. For purposes of determining
BTU consumption, assume that all engine operat
ing time will be at full load and at the speed re
quired for rated pumping capacity. (Engine speed
is shown on the performance curve on the Gor
man‐Rupp Specification Data Sheet for the pump).
Short periods of idle speed time need not be con
sidered, as fuel consumption at idle is negligible. If
extended periods of idle speed time are anticipat
ed, calculated fuel consumption should be in
creased accordingly.
Consult the local LPG supplier to determine the
size of fuel tank required. This determination will be
based on the BTU/HR consumption rate, total BTU
storage required, local climate conditions, BTU
content of the fuel to be supplied, and installation
parameters such as local code restrictions and
proposed tank location.
On all units, be sure to specify that the tank will be
used for vapor withdrawal. In this type of system,
fuel is taken from the top of the storage tank in the
vapor state, eliminating the need for a LP gas con
verter, which converts liquid fuel to the vapor re
quired by the engine fuel mixer. The vapor with
drawal system provides an adequate amount of fu
el for an engine the size of which is on the pump
unit. However, if fuel is used at a rate excessive for
the tank size and ambient temperature conditions,
freezing may occur in the tank. This problem can
usually be anticipated by the LPG supplier and
may require selection of a larger tank.
REGULATORS (NATURAL GAS)
The engine is equipped with a natural gas regula
tor designed to supply the engine with natural gas
gas at 6 inches of water column.
Gorman‐Rupp has provided a secondary natural
gas regulator. This regulator has a maximum inlet
pressure of 15 psi (1,0 bar) and an outlet pressure
range of 6 to 14 inches (152 to 356 mm) water col
umn. This regulator can be used to supply the 10
inches (254 mm) the engine requires when the gas
supplier can only supply a pressure greater than
0.5 psi (0,03 bar). The regulator is shipped loose
for field installation and should be located before
any fuel lock‐off valves in the gas supply line.
REGULATORS (LP GAS)
The engine is equipped with an LP gas regulator
designed to supply the engine with LP gas at 6
inches of water column. Gorman‐Rupp provides a
primary regulator and a secondary regulator with
the pump unit.
The pressure in an LPG storage tank with vapor
withdrawal will vary depending on temperature.
For example, the pressure of propane at 70°F
(21°C) is approximately 100 psi (6,9 bar), but this
pressure increases to 180 psi (12,4 bar) at 100°F
(38°C) and decreases to 18 psi (1,2 bar) at 10°F
(-23°C). The primary (first stage) regulator is ca
pable of accepting this wide range of inlet pres
sures while maintaining approximately 10 psi out
let pressure (see the note below) and should be lo
cated on or near the storage tank. The secondary
(second stage) regulator then reduces this 10 psi
(0,6 bar) pressure at its inlet to an outlet pressure of
10 inches of water column (see the note below).
This regulator should be located before any fuel
lock‐off valve in the supply line. If this regulator is
located after a fuel lock‐off valve the operation of
the regulator will be affected by sudden pressure
increase when the lock‐off valve opens. The regu
lators are sized to deliver the fuel flow required by
the engine during full load operation while main
taining pressures within specified limits.
NOTE
The primary regulator output pressure of 10 psi (0,7
bar) is used to illustrate a typical system. Actual
pressure may be higher or lower depending on
code requirements. The primary regulator supplied
