Technical data

11
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 fully pumped
conventional indirect hot water systems utilising an indirect
double feed cylinder. This appliance is not suitable for use on
gravity systems.
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 must be made on the
same side of the boiler depending on the position of the boiler
within the Outdoor Pack.
9.3 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.
9.4 The pressure jet burner fitted to the appliance has full
automatic control and hence there is no requirement for heat
leak radiators.
9.5 The appliance is suitable for connection to open vent or
sealed primary systems.
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.
9.7 Drain cocks should be fitted on the lowest points on the
system to allow draining of the appliance and system.
9.8 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.
9.9 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.
NOTE: Exposed pipework should be properly insulated to
protect against frost damage.
Open Vent Primary System (See Fig. 8).
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 recommended 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. 8.
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. 9 and 10).
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
therequirements 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 a
sealed system:
1. Safety valve - 3 bar
2. Pressure gauge - 0 to 4 bar.
3. Expansion vessel
4. Automatic air vent.
9. Heating And Hot Water System
Primary
cold feed
(15mm min.)
Heating vent
(22mm min.)
Fig. 8. Typical fully pumped open vent system (Honeywell ‘Y’ plan).
Feed and
Vent Cistern
Diverting
valve
Pump
Radiator
S.H. – Minimum static head 1m (3ft)
measured from the highest point in the
heating system (top surface of the appliance
or highest point in the heating system) to the
water level in the feed and expansion tank
N.B. A drain cock should be
installed at the lowest point of
the heating circuit
Domestic hot
water cylinder
S.H.
S.H.
150mm max
Boiler
Automatic bypass valve to be fitted
where thermostatic radiator valves
are fitted on all radiators