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12.3.2
EXPANSION VESSEL SIZING
The following information is based on an inlet pressure of 3.5 bar. If a different inlet pressure is to be used, please
consult BS6700.
V V = S V * e
0.45
Where:
V V
=
Vessel Volume
S V
=
System Volume
e
=
Coefficient of Expansion
Stored Temp.
Stored Temp.
12.3.3
COEFFICIENT OF EXPANSION OF WATER AT 3.8 BAR COLD FILL PRESSURE
12.4
DE-STRATIFICATION
If the hot water system does not include a constantly circulated building return, it is recommended that a de-
stratification pump is fitted, between the building flow connection and the drain connection of the storage vessel, to
ensure an even temperature distribution throughout the stored water. De-stratification pump kits are available as
ancillary items; please contact Lochinvar Limited for details.
12.5
CIRCULATING PUMPS
In order to ensure the correct flow rates through the water heater, the unit requires a bronze glanded pump sized to
overcome the resistance of the heat exchanger and a primary pipework loop. Lochinvar will supply a suitable bronze
glanded shunt pump with each water heater as shown in Section 12.5.1. The primary loop should be no longer than
14 metres plus the following fittings:
6 x 90 Elbows
2 x Unions
2 x Full bore lever ball valves
2 x Tee fittings (cold feed & building return)
For longer distances or a greater number of fittings, the pump may have to be resized.
The specification of this type of pump ensures that the bronze body and associated parts in contact with water are
suitable for potable use. A "glanded" construction is required to ensure that any scale in the system does not build up
within the pump and cause a resistance that can lead to a loss of water flow. Glandless (canned rotor) pumps are not
recommended due to the fact that in hard water areas, scale can build up within the rotor and failure can occur, not
only of the pump but also the heater itself. The warranty will be void if a failure of the heat exchanger occurs due to a
"glandless" pump being used.
Model
Differential (K)
EKW46CE
EKW61CE
EKW86CE
EKW116CE
EKW146CE
EKW176CE
EKW206CE
EKW236CE
12.5.1
FLOW RATES AND SHUNT PUMP SIZES
Lochinvar will supply a suitably sized pump with all EcoKnight™ water heaters based on the parameters shown
above, for projects outside these parameters the pump will have to be re-sized.
(See 12.3.3)
30
35
C
e
0.005
0.006
65
70
C
e
0.020
0.023
FLOW
(Litre/sec)
10.0
0.98
10.0
1.17
10.0
1.80
10.0
2.82
10.0
3.19
12.2
3.30
12.2
4.00
13.3
4.20
40
45
50
55
0.008
0.010
0.012
0.015
75
80
82
85
0.026
0.030
0.031
0.033
Total System Pressure
Loss (Meter- H
7.32
6.71
6.07
8.51
7.93
7.90
9.80
9.40
60
0.017
90
0.037
Shunt Pump supplied
0)
2
LM900151A
LM900151A
LM900141A
LM900140A
LM900140A
LM900140A
LM900149A
LM900149A
43
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