A.O. Smith BFC - 28 - Manual (Page 23)

Installation diagram
Release R.1.3 UK 23
is
Table 3.6 Gas data
3.5 Installation diagram Figure 3.3 shows the water and gas connection diagrams for unvented and
vented installations. The following paragraphs, describing the connections in
detail, make reference to these diagrams
Gas category data II
2H3+
Unit BFC 28 BFC 30 BFC 50 BFC 60
Data for natural gas 2H: G20-20 mbar
Orifice diameter mm 4.90 5.10 7.00 7.10
Nominal load (upper value) kW 32.1 34.5 52.6 63.2
Nominal capacity kW 30.3 32.8 48.6 59.6
Supply pressure mbar 20 20 20 20
Burner pressure mbar 8.5 8.5 8.5 11.5
Gas consumption (1) m 3 /h 3.1 3.3 5.0 6.0
Data for LP gas 3+
General
Orifice diameter mm 2.50 2.60 3.40 3.80
Restrictor diameter mm n.a. n.a. n.a. n.a.
G30-30 mbar (butane)
Nominal load (upper value) kW 30.7 32.8 50.6 59.4
Supply pressure mbar 37 37 37 37
Burner pressure (2) mbar 37 37 37 37
Gas consumption (1) kg/h 2.2 2.4 3.7 4.3
G31-37 mbar (butane)
Nominal load (upper value) kW 29.0 30.9 50.3 59.1
Supply pressure mbar 37 37 37 37
Burner pressure (2) mbar 37 37 37 37
Gas consumption (1) kg/h 2.1 2.2 3.6 4.2
(1) Based on 1013.25 mbar and 15 o C.
(2) If using a flat sealing plate instead of a burner pressure regulator, it is assumed that the burner pressure is equal to the supply pressure.
In practice however, the burner pressure will be lower.