Alpha E-Tec Plus 28NX Design, Installation And Servicing Instructions page 7

3.2 TECHNICAL PERFORMANCE DATA - LPG - PROPANE GAS (Cat I3P 3P - G31 37 mbar)
Heat input gross - DHW
Heat input gross - CH
Heat input minimum gross
Gas supply pressure nominal (minimum)
Gas burner injector
CO2 at maximum DHW output
CO2 at minimum output
Gas rate at maximum output
SAP/SEDBUK seasonality efficiency 2005
SAP/SEDBUK seasonality efficiency 2009
CO (maximim)
Flue mass at maximum output
Flue mass at minimum output
Flue temperature at maximum output
Flue temperature at minimum output
Note: OtherTechnical data is the same as NG data.
3.3 FLUE LENGTHS
A 500 mm or 1000 mm Easy-Flue terminal kit with 90° bend or horizontal terminal is available.
CD 750 mm and 1000 mm flue extensions are available.
Length of Flue Required:-
Rear Flue = wall thickness + 180 mm (includes terminal).
Side Flue = wall thickness + distance between wall and side of boiler + 265 mm (includes terminal).
Vertical Flue = distance from top of boiler side panel to required roof position minus 1000 mm for vertical terminal assembly.
Maximum horizontal flue length = 12 m.
Maximum vertical flue length including terminal is 14 m.
Each additional CD 90° Bend is equivalent to 1.3 m of flue length.
Each CD 45° Bend is equivalent to 0.9 m of flue length.
The CD Vertical Flue terminal assembly is equivalent to 1 m of flue length.
3.4 PUMP
The boiler is equipped with a variable speed low power consumption pump.
During the DHW mode, the pump always runs at the maximum speed.
During the CH mode, three different functioning modes of the pump are available, Proportional, Fixed and Constant T.
Proportional - The pump speed is controlled automatically in order to give a proportional pump head, the pump speed
varies based on the heat output supplied by the burner - the greater the heat output the higher the pump
speed. See parameter A.4 in Section 6.14.
It is possible to adjust the pump speed range in the boiler parameter menu.
Fixed - The pump runs at a constant speed by setting the same minimum and maximum speeds. See parameters
A.2 and A.3 in Section 6.14.
Constant - The pump speed is controlled to give a set T. See parameter A.4 in Section 6.14.
The boiler is factory set to Constant - to achieve a T of 15°C (parameter A.4 is set to 15)
By-pass Regulation - The boiler leaves the factory with the by-pass open.
If necessary, the by-pass can be adjusted to the system requirements from maximum (by-pass open) to minimum
(by-pass closed). Adjust using a flat head screwdriver, turn anticlockwise to close the by-pass, and clockwise to open.
With the by-pass in the closed position the system must have a continuous open circuit.
If zone valves are used in the system an external by-pass must be fitted.
When the pump is running, the symbol
When the pump power supply on, the symbol
If the pump detects an alarm, the symbol
E-Tec Plus 28NX
kW 31.2
kW 26.6
kW 4.9
mbar 37 (32)
mm 3.70
% 10.2 (10.0 - 10.4)
% 9.7 (9.5 - 9.9)
kg/h (g/s) 2.23 (0.62)
% 90.8
% 89.5
ppm 250
Kg/h 48
Kg/h 8
°C 69
°C 56
flashes with green light.
is steady with green light.
is steady with red light.
Alpha E-Tec Plus 28NX, 33NX and 38NX - Technical Data
E-Tec Plus 38NX
E-Tec Plus 33NX
35.5 41.3
31.1 35.5
5.4 6.5
37 (32) 37 (32)
4.20 4.90
10.0 (9.9 - 10.3)
10.3 (10.1 - 10.5)
9.6 (9.4 - 9.8) 9.4 (9.1 - 9.5)
2.54 (0.71) 2.95 (0.82)
90.7 90.6
89.4 89.3
250 350
54 64
9 11
79 85
61 64
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