Hamworthy Milborne 500 Series Design Installation, Commissioning And Operating Instructions page 18

Room Sealed Flue Installations Type C63
Figure 8.3 shows the twin pipe flue adaptation kit fitted to a Milborne 502 boiler. This allows the air supply and the
flue to be piped using separate ducts for room sealed applications.
It is most important that horizontal flue terminals are Figure 8.3
positioned at least to the minimum requirements, as
shown in Figure 8.5, from other features of the
building , i.e. opening windows etc.
Air supply inlets must be positioned at least 300 mm
from flue terminals to prevent flue gas recirculation.
We recommend that flue terminals are discharged
higher than air inlets.
For C53 twin type pipe installations the maximum
equivalent length of 30 metres includes both the
requirements for the air inlet pipe and flue pipe.
To comply with the requirements of the Clean Air Act 1956 a maximum of three (3) 50 kW modules may be
terminated with horizontal flue discharges.
Connection to a Flue Gas Header
The design of the flue system for the installation of several Milborne 500 Series boilers will be easier if a 125 mm
diameter, polypropylene flue gas header with male / female connections is used.
The header is designed to collect the flue gas
from the two 50 mm flue pipes of a Milborne
Figure 8.4
502, each of which contains a flue gas non-
return valve.
When using the flue gas header for up to
three (3) boiler assemblies connected in
series, the minimum distance required
between the assemblies (150 mm) must be
complied with; see figure 8.4.
In this way, the male end of one of the two
headers will connect more readily to the
female connection of the adjacent header.
Note: When using the 125 mm diameter flue
header the maximum number of 50kW
modules acceptable in a single flue system is
six (6), or 3 x 502 models.
Maximum equivalt flue length when using the
125 mm diameter flue header with 6 x 50kW
modules remains at 30 metres, with a 4
metres reduction for each 90° bend in the flue
system and 3 metres for each 45° elbow.
Maximum pressure available at flue
connection to an individual 50 kW module is
0.7 kPa (7 mbar)
Note: Air supply ducts must not be connected together when using room sealed applications. Only
individual air ducts for each module are acceptable.
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HAMWORTHY HEATING LTD MILBORNE 500 SERIES 500001130/A