25
10.0
WATER CONNECTIONS
10.1
GENERAL
Adaptors are required to convert the NTP (male) thread on the heat exchanger to BSP (female). These
adaptors can be found in the packing carton. The BSP section of the adaptor is indicated with blue paint.
The requirements of minimum water flow are given in
Table 10.2
. Recommendations for the water circulation system
are given in
BS6644
and
CP 342
. The following notes are of particular importance.
1.
It is strongly recommended that a low velocity header be used to separate the primary circuit from the
secondary circuit.
2.
Circulating pipework not forming part of the useful heating surface should be insulated. Cisterns, expansion
vessels and pipework situated in areas exposed to freezing conditions should also be insulated.
3.
Drain valves must be located in accessible positions that will permit draining of the entire system including
the unit and the storage vessel.
4.
Tapping sizes for connection to the system are detailed in
Table 3.1
.
5.
Ideally, individual valves should be fitted to each unit to enable isolation from the system. The arrangement
must comply with the requirements of
BS6644
.
A suitably sized low velocity header is available from Lochinvar Limited as ancillary item.
10.2
OPEN VENTED SYSTEM ARRANGEMENT
The Lochinvar EcoKnight™ can be used in an open vented arrangement provided that a vent pipe in accordance with
CP 342
or
BS6644
as appropriate is fitted. The minimum static head requirement for an open vented system is 0.5
bar.
10.3
SEALED SYSTEM ARRANGEMENT
If a sealed system arrangement is required, a suitable pressurisation unit is available from Lochinvar Limited on
request. Sealed systems should incorporate a safety valve with a lift pressure no greater than the maximum pressure
rating of any component in the heating system. The maximum working pressure of the boiler is 11.0 bar. A suitably
sized expansion vessel should also be fitted to the system in accordance with
BS4814
.
10.3.1
EXPANSION VESSEL SIZING
The following information is based on a static head of 35 metres and a cold fill pressure of 3.8 bar. If the cold fill
pressure is to be different, please refer to
BS4814
.
V V = S V * e
0.45
Where:
V V
=
Vessel Volume
S V
=
System Volume
e
=
Coefficient of Expansion
(See Table 10.1)
Flow Temp.
C
30
35
40
45
50
55
60
e
0.005
0.006
0.008
0.010
0.012
0.015
0.017
Flow Temp.
C
65
70
75
80
82
85
90
e
0.020
0.023
0.026
0.030
0.031
0.033
0.037
TABLE 10.1
COEFFICIENT OF EXPANSION OF WATER AT 3.8 BAR COLD FILL PRESSURE
