10
4.0 Technical Data
© Baxi Heating UK Ltd 2016
4.1
Promax 24, 28 & 33 Combi ErP
Flue Terminal
Diameter
100mm
Dimensions
Projection
125mm
Outercase Dimensions
Casing Height
- 780mm
Overall Height Inc Flue Elbow
- 940mm
Casing Width
- 450mm
Casing Depth
- 345mm
Central Heating Primary Circuit
Pressures
bar
Safety Discharge
3
Max Operating
2.5
Min Operating
0.5
Recommended Operating Range
1-2
DHW Circuit
bar
Pressures
Max Operating
8
Min Operating
0.15
Flow Rates
(24)
(28)
(33)
l/min l/min
l/min
DHW Flow Rate
@ 30
o
C Rise
11.43
13.3
15.7
DHW Flow Rate
@ 35
o
C Rise
9.8
11.5
13.5
Min Working
DHW Flow Rate
2
2
2
Pump
Available Head
See graph below
Connections
copper tails
Gas Supply
-
22mm
Central Heating Flow
-
22mm
Central Heating Return
-
22mm
Cold Water Mains Inlet
-
15mm
DHW Flow
-
15mm
Pressure Relief Discharge
-
15mm
Temperatures
C.H. Flow Temp
(adjustable)
25°C to 80°C
max
(± 5°C)
D.H.W. Flow Temp
(adjustable)
35°C to 60°C
max
(± 5°C)
dependent upon flow rate
0
200
400
600
800
1000
1200
0.5
1
1.5
2
2.5
3
3.5
4
Metre (wg)
Flow Rate (l/h)
Pump - Available Head
0
5
5.5
4.5
Clearances
Above Casing
175 mm Min
Below Casing
150 mm Min*
Front
450 mm Min
(For Servicing)
Front
5 mm Min
(In Operation)
L.H. Side
5 mm Min
R.H. Side
5 mm Min
(In Operation)
*This is MINIMUM recommended dimension. Greater
clearance will aid installation and maintenance.
Heat Output CH Pn
(Non-Condensing)
Max
Min
24 model
kW
20.6
6.8
28 model
kW
24.7
8.7
33 model
kW
28.9
9.4
Electrical Supply
230V~ 50Hz
(Appliance must be connected to an
earthed supply)
Power Consumption
(Watts)
24 - 85 W
28 - 120 W
33 - 125 W
Electrical Protection
IPX5D
Internal Fuse Rating
F2L
Appliance Category
CAT I
2H
Inlet Pressure
(Natural Gas - G20)
mbar
20
Injector
(Natural Gas - G20)
7.5mm (24 & 28 model) 12mm (33 model)
Appliance Type
C
13
C
33
C
53
Heat Output CH Pnc
(Condensing)
Max
Min
24 model
kW
21
7.4
28 model
kW
25.9
9.5
33 model
kW
30.3
10.2
Heat Output DHW
Max
24 model
kW
24
28 model
kW
28
33 model
kW
33
Max Gas Rate
(Natural Gas - G20)
(After 10 mins)
24 model
m
3
/h
2.6
28 model
m
3
/h
3.1
33 model
m
3
/h
3.6
Condensate Drain
To accept 21.5mm (
3
/
4
in) plastic waste pipe
Heat Input CH Qn Hs
(Gross)
Max
Min
24 model
kW
22.7
7.8
28 model
kW
27.4
10
33 model
kW
32.1
10.8
Heat Input DHW Qnw Hs
(Gross)
Max
24 model
kW
27.4
28 model
kW
32.1
33 model
kW
37.7
External Fuse Rating
3A
SAP 2009 Annual Efficiency
24 & 28 - 89.0 %
33 - 88.9 %
This value is used in the UK Government’s Standard
Assessment Procedure (SAP) for energy rating of
dwellings. The test data from which it has been
calculated has been certified by 0085.
Product Characteristic Database
(SEDBUK)
Weights (kg)
(24)
(28)
(33)
Packaged Boiler Carton 45.5
45.5
47.0
Installation Lift Weight
40.2
40.2
41.7
NOTE:
All data in this section are nominal values
and subject to normal production tolerances.
IMPORTANT:
Where Low Flow Taps or Fittings are
intended to be used in the DHW system connected it is
strongly recommended that the DHW flow rate DOES
NOT fall below 2.5l/min. This will ensure reliable
operation of the DHW function.
Expansion Vessel
-
(For Central Heating only.
Integral with appliance)
bar
Min Pre-charge Pressure
0.5
(24 & 28)
(33)
litre
litre
Max Capacity of
CH System
125
125
For greater system capacities an additional
expansion vessel MUST be fitted
.
Primary Water Content
of Boiler (unpressurised)
2.5
2.8
NOx Class
5
