Heating And Hot Water System; Electrical - Bosch WORCESTER DANESMOOR UTILITY 12/14 Installation And Servicing Instructions

9. Heating And Hot Water System

The heating and hot water system must be provided in accor-
dance with the current Building Regulations.
9.1 The appliance is suitable for connection to all conventional
indirect hot water systems utilising an indirect double feed cylinder.
9.2 The flow and return sockets are located at the rear of the
appliance, two at high level (flow) and two at low level (return).
Connection of the flow and return sockets can either be made on
diagonally opposite sockets or on the same side of the boiler.
9.3 Provision has been made for locating the circulating pump
within the appliance cabinet. If required, the socket located in
the top front of the boiler should be used and the flow pipe run
either side of the boiler (See Figs. 2 and 3).
9.4 On new installations it is recommended a room thermostat
or programmable room thermostat is used in the main zone and
thermostatic radiator valves are used in further heating zones.
On existing systems where a room thermostat is already fitted it
is recommended to fit thermostatic radiator valves at least in the
sleeping zones.
A automatic system bypass should be fitted on heating systems
when all of the radiators are fitted with thermostatic radiator valves.
9.5 The pressure jet burner fitted to the appliance has full
automatic control and hence there is no requirement for heat
leak radiators.
9.6 Any unused boiler tappings should be plugged prior to
filling. It should be noted that the flow tapping on the front of the
boiler requires plugging when not used.
9.7 The primary system should be flushed and treated in
accordance with the recommendations of BS 7593 before the
system is handed over to the user.
9.8 The pump should be set in accordance with the heating load
requirements to give a flow and return differential temperature
of 11°C under full load conditions.
Open Vent Primary System (See Fig. 12).
The following points are for guidance only. The system installation
should be carried out in accordance with BS 5449: Part 1.
1. System Pipework
The first metre of pipework from all appliance connections must be
in copper; afterwards copper or plastic pipe can be used. The
plastic pipe must be manufactued to BS 7291 and installed to BS
5955 part 8. It is important to protect the system components; the
plastic pipe specified must be resistant to the ingress of oxygen.
2. Feed and Expansion System
The feed and expansion pipes must rise continuously from the
appliance and must be of the minimum diameter shown in
Fig. 12.
The cistern must be arranged to provide a minimum static head of
1 metre above the top of the highest point in the heating circuit.
3. Filling and Venting
Air in the appliance is expelled through the vent pipe or
dissipated into the system. Manual air vents should be fitted at
any high points in the system.
Sealed Primary System (See Figs. 13 and 14).
The appliance is supplied with a manual reset high limit thermostat
and may therefore be fitted to a sealed heating system.
1. System Pipework
Copper pipework must be used when installing the appliance on
a sealed system.
2. General
The system should be installed in compliance with the
requirements of BS5449: Part 1. The boiler must be fitted with a
spring loaded safety valve set to operate at 3 bar (45 psi) and the
pipe connections made throughout the system must be capable
of sustaining a pressure of up to 3 bar.
The following is a list of major items which must be fitted to the
system:
1. Safety valve – 3 bar
2. Pressure gauge – 0 to 4 bar.
3. Expansion vessel
4. Automatic air vent
.

10. Electrical

(See Fig. 15).
10.1 The wiring between the appliance and the electrical supply
shall comply with current IEE wiring regulations (and any local
regulations which apply) for fixed wiring to a stationary appliance.
NOTE: It must be possible to completely isolate the appliance.
10.2 To gain access to the electrical terminal strip.
1. Isolate the mains electrical supply.
2. Remove the cabinet front panel by pulling forwards to
release the ball studs.
3. Pull the thermostat control knob forwards to remove from
its spindle.
4. Undo the facia retaining screws and remove the plate.
10.3 Mains Wiring
Mains supply - 230V AC ~ 50 Hz 5A External Fuse to
BS1362.
LIVE - Brown, NEUTRAL - Blue, EARTH - Green/Yellow
Mains Cable: 0.75mm 2
The supply to the boiler must be the only electrical supply to the
system. This ensures the safety of a single fused supply.
The mains supply cable should be connected into the terminals
marked L (Live), N (Neutral) and E (Earth) on the appliance
terminal strip and securely held in the cable clamp located in the
right-hand side of the electrical tray base. To secure the cable,
remove the clamp retaining screw and pull its inner body out to
allow the cable to be fed through. With the cable in position refit
the screw and fully tighten to grip the cable. Feed the cable
between the side panel and the boiler insulation jacket and route
to the connection point avoiding any hot surfaces.
The appliance must be earthed.
10.4 Programmer
A time clock or programmer may be added to the control system. A
two channel programmer will allow independent control of the central
heating and hot water.
NOTE: Under no circumstances should the timer be connected to
a separate electrical supply. Safety is assured from a single fused
supply to the boiler.
10.5 Safety Check
In the event of an electrical fault after the installation of the
appliance, the electrical system shall be checked for short
circuits, fuse failure or incorrect polarity of connections.
10.6 Pre-wired Remote Y Plan or S Plan System
(See Fig.16).
If the system is fully pre-wired at a junction box remotely from
the boiler it can be connected to the boiler. The diagram shows-
connection details of two popular proprietary systems
(Honeywell and Invensys), for these and other systems from
other manufacturers always use the boiler instructions in con-
junction with the system instructions.
10.7 Frost Protection
For full frost protection a frost thermostat should be fitted so
that both the boiler and the circulating pump circuits are
energised under frost conditions.
16
(24 x 0.20mm) to BS 6500 Table 16.