HAMWORTHY HEATING LTD
MILBORNE 500 SERIES
500001130/A
NOTE: In certain circumstances it is necessary
to fit a larger LPG orifice to the gas valve air
inlet port. If poor ignition is experienced after
commissioning the boiler then the larger orifice
may be fitted. It is important to commission the
boiler first, as correctly setting the gas valve
offset for clean combustion may overcome
initial poor ignition.
The alternative LPG orifice is sized at 6.75mm
internal diameter and is fitted in exactly the same
way as the 6.5mm diameter orifice. If fitting the
larger orifice then the 6.5mm diameter orifice must
first be removed.
Notes:
1. The procedure for modification and
adjustment of the parameters at the Master
Control Panel of the Milborne 501 and Milborne
502 Master Boilers is detailed in Section 19.0 of
this manual.
2. Once the boiler has been modified for LPG
firing it is essential to complete the full
commissioning procedure to all boiler modules
as detailed in Section 15.0
3. If after commissioning, the larger orifice has
to be installed then the full commissioning
procedure as detailed in Section 15.0 must again
be completed.
Figure 21.8
21.8 Reassembly Procedure
Ensure that all the components that have been
removed and modified are clean. Position the
venturi to the gas valve and refit 3 screws that were
previously removed in step 21.4. Ensure the 3
screws are securely tightened to prevent leaks at
the venturi to gas valve joint.
21.9 Modifying the Boiler Parameter, Master
Boiler Only
It is essential to modify the boiler parameter number
36 to identfy the type of gas being used. This must
also take account of the flue length as indicated in
the table below. To modify the parameter it is
necessary to reinstate the gas and electrical
supplies.
WARNING! As the boiler MUST NOT fire before
the parameter is modified ensure that there is no
demand for heat from any of the connected
circuits and time clock controls.
Parameter Description Range Default
Specification
36
Type of Gas
1-7
1
1= Natural Gas with equivalent flue length < 15m
2= Natural Gas with equivalent flue length > 15m
3= LPG with equivalent flue length < 15m
4= LPG with equivalent flue length > 15m
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