HAMWORTHY HEATING LTD
WESSEX-HE 200 BOILER
500001008/K
9
(unvented) Hot Water System.
In order to correctly size a Pressurisation Unit for any
Heating System certain parameters are required.
These are: -
1) Static height of highest component in system.
2) System volume - if not known a general rule of
thumb of 10litres/kW installed boiler power can be
used.
3) Maximum flow temperature, i.e. most systems run
at 82°C.
4) Maximum system hot working pressure, generally
given in bar gauge.
From the above information Hamworthy Heating can
size the pressurisation unit and also the expansion
vessel required.
Care must be taken in sizing expansion vessels to
ensure maximum acceptance factors are not
exceeded. Normally manufacturers of vessels
impose a limit of 0.5. This value must not be
exceeded at any time during the operation of the
boiler: this includes the over pressure condition
should a safety valve lift.
Consideration should also be given to sizing of the
safety valve(s) in the system. See
BS 6759 Part 1
(ISO 4126)
and
BS 6644
.
See also
BS 6880 Part 1
for design considerations.
9.0 ELECTRICAL SUPPLY
See
BS 6644
.
WARNING: THIS APPLIANCE MUST BE
EARTHED.
Wiring external to the boiler must be installed in
accordance with the IEE Regulations and any local
regulations, which apply. Wiring must be completed
in heat resistant 3-core cable. (Size 1.0mm
2
CSA)
Boilers are normally supplied for 230 volts. 50 Hz.
Internal fuse rating of each module is 2 Amperes.
External fuses should be 5 Amperes for all boilers.
The method of connection to the mains electricity
supply must facilitate complete electrical isolation of
the boiler module with a contact separation of at least
3mm in all poles. A mains isolator must be provided
adjacent to the boiler in a readily accessible position.
The supply should only serve the boiler. Further
details regarding connection to the electricity supply
are given in
BS 3456
(CEE 10 Part 1, CEE11 Part 1).
NOTE!
Volt free contacts electrical supplies must
also be isolatable when fitted (see note on fascia).
9.1 Mains Cable Connection
The path of the mains cable is shown in Figure No. 4.
The length of the conductors between the cable
anchorage and the terminals must be such that the
current carrying wires become taut before the earth,
should the cable slip out at the cord anchorage.
9.2 Boiler Wiring Diagram
The boiler-wiring diagram is shown in Figure No. 5.
This wiring diagram is also fitted inside each boiler
cover.
9.3 Indication Signals and Volt Free Contacts
If the boilers are to be wired to external indicator
lights or alarms, it is preferred that each module
should be fitted with a Volt Free Contact kit to divorce
any external wiring from the internal control wiring.
The kit (P No. 563605145) may be fitted prior to
delivery or on site, the mounting rail for the 3 relays
being pre-installed on each module. 3 signals can be
derived from the controls: -
a)
Normal run -
derived from terminal 11 on
main terminal rail.
b)
Overheat - derived from terminal 8 on main
terminal rail.
c)
Lockout - derived from terminal 7 on main
terminal rail.
Each of these 230V signals are wired to a separate
relay coil and the volt free change over contacts can
