FULTON VMP Series - LPG Gas Supply Installation (Propane;Butane)

VMP-IOMM-2018-2
Fulton Ltd
Page 13
INSTALLATION - 2
2.5.1.3  
LPG Boilers should be installed to the requirements of IGE/UP/10 March 2001 and only by
experiencedengineersfamiliarwithLPGring.AnL.P.gasboilerissimilarindesigntoanatural
gas boiler, the main differences are important and must be taken into account when installing the
boiler and ordering spare parts.
WheninstallinganL.P.gasboiler,thefeedfromthebulktanksupplymustbettedwithasupply
governor which is set to reduce the supply feed pressure to the boiler governor to between 50
mbar (min.) and 80 mbar (max.).
For PROPANE: Theboilergovernormustbeadjustedtogivearingpressureof25mbarat
the test point provided at the elbow on the gas train.
For BUTANE: Theboilergovernormustbeadjustedtogivearingpressureof20mbaratthe
test point provided at the elbow on the gas train.
Gas Pressure Alarm Indicator Light
For L.P.G. applications the inlet pressure switch is used to protect the system from over
pressure and should be set at 100 mbar.
Further information
Firing LPG fuels in a Fulton Vertical boiler is relatively straightforward, however the nature of the
fuelmakesitdifculttoensurethatthecorrectgasowrateisachievedwhencommissioningand
servicing the burner.
LPG is stored as a liquid at high pressure, which is vaporised as the pressure reduces through
the pressure regulator at the discharge from the tank. The storage tank pressure regulators
typically reduce the pressure down to 150 - 500 mbar, which is too high for the inlet to the gas
control valve on the Fulton burner. An intermediate or Service Governor is therefore required to
reduce the pressure further to below 80 mbar.
The siting of the LPG storage tank can be crucial particularly in environments where high ambient
temperatures may be experienced. The effect of world wide temperature changes such as caused
bysolargain,canresultinsignicantLPGsupplypressurechangeovera24hourperiod.
The consequences of temperature and pressure changes, is to vary the density of the gas
suchthataccurate,consistent,andmeaningfulmeasurementofthegasowrateisdifcult.
Calibrating,gasowmeterstoanydegreeofpracticalaccuracyisextremelydifcult.Atbestan
LPGgasmetergivesanapproximationofthegasowrate,howevertheinstallationofameteris
essential.
Wherenometeringisavailabletheonlyavailablecriteriatoassesstheowrateistheburner
inlet gas supply pressure at the test nipple on the last elbow prior to the gas entering the burner.
This pressure would normally be established during works testing after manufacture, however
LPGringisnotpossibleattheFultonBoilerWorksBristolfactory,forbothpracticalandsafety
reasons.
TheguresgivenintheOperationandMaintenanceInstructions,arecalculatedguresbased
onpublisheddatafortheSpecicGravityofstandardPropaneandButaneat15.6°C.Inpractice
temperature,pressureandgasconstituentsvariations,aresuchthatthecalculatedgureshould
only be used as a guide.
LPGfuelsgenerallyproducehigherametemperatures(Butanebeingthehighest)whichmakes
itvitalthattheburnersarenotoverred,orareoperatedwithanysignicantlevelsofCarbon
Monoxide (CO) in the exhaust gas, which could lead to overheating of the boiler pressure vessel.