Unical ALKON 50 kW - Determination of Primary Boiler Pump or Boiler Pump System

19
Instructions for the installer
The size of the pumps must be determined
by installers or technical engineers
according to boiler data and system
design.
The water side resistance curve of the
boiler is shown in the following diagram.
The pump is not an integral part of the
boiler.
It is recommended to choose a pump with
the rate and delivery head at about 2/3 of
its characteristic heating curve.
The boiler pump must have a delivery head which can ensure
the water flow rate as shown in the diagram “Water pressure
losses”.
The following table gives an indication of the pump’s flow rate
in function of the Ät of the primary circuit if the installation has
a mixing header
Power supply in kW
Max flow rate
demanded in l/h (
ΔΔ
ΔΔ
ΔT 15K)
Portata nominale
richiesta in l/h (
ΔΔ
ΔΔ
Δ T 20K)
49,3
2826
2120
ALKON 50
68,5
3927
2946
ALKON 70
0
200 400 600 800
1000
1200 1400
1600
1800
2000
2200
2400 2600
2800 300
0
3200 3400
3600
0
200
400
600
800
1000
0
1200
1400
1600
1800
2000
2200
2400
2600
2800
3000
3200
0
3400
3600
3800
4000
4200
4400
4600
4800
5000
5200
5400
5600
5800
6000
6200
6400
6600
6800
7000
7200
7400
7600
7800
8000
3800 4000 4200 4400 4600 4800 5000
ALKON 50
ALKON 70
3.8 - DETERMINATION OF PRIMARY BOILER PUMP OR BOILER SYSTEM PUMP
NOTE: The use of a mixing header fitted between the boiler circuit and the system circuit is
always advisable. It becomes INDISPENSABLE if the system requires flow rates superior to the
maximum permitted boiler flow rates, which is to say lower than 15K.
For a
ΔΔ
ΔΔ
ΔT 20 K, the max. water flow rate requested is 2120 l/h.
From the graph of the boiler’s pressure losses, it can be determined that the pump must be able
to guarantee a delivery head of at least 1,6 mH2O.
Pressure losses (mmH2O)
Q: water flow rate (l/h)
WATER SIDE PRESSURE LOSSES