HAMWORTHY HEATING LTD
WESSEX-HE 200 BOILER
500001008/K
31
1.0 INTRODUCTION
The operation of the Wessex-HE 200 range of boilers
on LPG - Propane (3
rd
family)I
3P
gas is similar to that
on Natural Gas (2
nd
family)I
2H
and the design and
installation details described in the main body of the
Installer’s Guide should be followed. There are,
however, differences in the construction and setting
of the Propane fired boiler module which are as
follows: -
a) The pilot injector marked 200 for Natural Gas is
replaced with a smaller injector marked 35 for
Propane.
b) The main gas orifice (located and attached in the
first flange at the control valves common outlet -
see Figure No. 6) sized at 18mm DIA for Natural
Gas is supplemented by the addition of a smaller
orifice sized at 10mm DIA for Propane (located
between the flanges).
c) The bypass gas solenoid valve with an inactive
governor fitted for Natural Gas is replaced with a
gas solenoid valve with active governor for
Propane. Both main valves are therefore identical
when firing Propane and also identical to the
active governor valve used on Natural Gas with
no change of spring.
d) The nominal gas inlet pressure of the Propane
should be 37mbar.
e) The gas orifice pressure drop set at 2.6mbar
during commissioning for Natural Gas is
increased to 17.5mbar for Propane.
f) Relevant labels are replaced to indicate the
appropriate gas for which the boiler module is set
up to fire.
The following tables, paragraphs and figures, using
the same numbering system as the main Installer’s
Guide, highlight the different values and procedures
to be used when firing Propane and should be used
in conjunction with the main Installer’s Guide.
APPENDIX ‘A’ TO INSTALLER’S GUIDE FOR
WESSEX-HE 200 BOILER RANGE
INFORMATION RELATING TO PROPANE FIRING
NOTE!
LPG FUELS - IT IS STRONGLY RECOMMENDED THAT, ON LPG INSTALLATIONS, GAS DETECTION
EQUIPMENT BE FITTED. THIS EQUIPMENT SHOULD BE POSITIONED NEAR THE BOILER AND AT LOW
LEVEL. IT IS ALSO IMPORTANT THAT THE SPACE HOUSING THE BOILER IS ADEQUATELY VENTI-
LATED AT HIGH AND LOW LEVEL. REFER TO MAIN INSTALLER’S GUIDE.
2.2 Technical Data Table (Propane)
GENERAL DATA
Wessex-HE 200 Series
BOILER MODEL
Wessex-HE 200
Wessex-HE County
Boiler Input kW (Gross) - maximum
238
476
Boiler Input kW (Nett) - maximum
219.5
439
Boiler Output kW - maximum
200
400
FLUE DATA
Nominal Flue Spigot Internal Dia. (mm)
344
358
Approx. Flue Gas Temperature °C (Gross)
130
Approx. Flue Gas Vol. (0°C – 1013mbar)@ 9.0%
CO
2
(m
3
/h)
268
536
GAS DATA
Nominal Gas Inlet Press. (mbar)
37
Maximum Gas Inlet Press. (mbar)
45
Gas Flow Rate (m
3
/h)
8.9
17.8
Gas Setting Press. (mbar)
17.5
Differential Pressure Switch Setting (mbar)
1.2 (
Do not adjust
)
Orifice Dia. (mm)
10
Gas Inlet Connection Pipe Thread Size
Rp1
Pilot Injector Marking
35
