5
below the level of the heater (this can be achieved by
attaching a hose to the drain tap outlet spigot).
EXPANSION VESSEL
The expansion vessel accommodates expansion
that results from heating the water inside the unit.
The expansion vessel is pre-charged at 3.5 bar.
The expansion vessel must be connected between
the expansion valve (see Fig. 2, page 4) and the
PremierPlus cylinder (see Fig. 6, page 10). The
location of the expansion vessel should allow access
to recharge the pressure as and when necessary,
this can be done using a normal car foot pump. It is
recommended that the expansion vessel is adequately
supported. An expansion vessel wall mounting
bracket is supplied for this purpose and should be
fitted.
SECONDARY CIRCULATION
If secondary circulation is required it is recommended
that it be connected to the PremierPlus cylinder as
shown in Fig. 3, page 5 via a swept tee joint into the
cold feed to the unit. A swept tee joint is available as
an accessory (order code no. 94 970 033).
The secondary return pipe should be in 15mm pipe
and incorporate a check valve to prevent backflow.
A suitable WRAS approved bronze circulation pump
will be required. On large systems, due to the increase
in system water content, it may be necessary to fit an
additional expansion vessel to the secondary circuit.
This should be done if the capacity of the secondary
circuit exceeds 10 litres.
NOTE: We do not recommend use of a secondary
circulation circuit on direct units.
Pipe capacity (copper):
15mm O.D. = 0.13 l/m (10 litres = 77m)
22mm O.D. = 0.38 l/m (10 litres = 26m)
28mm O.D. = 0.55 l/m (10 litres = 18m)
HOT WATER OUTLET
The hot water outlet is a 22mm compression
fitting located at the top of the cylinder. Hot water
distribution pipework should be 22mm pipe with
short runs of 15mm pipe to terminal fittings such as
sinks and basins. Pipe sizes may vary due to system
design.
Cold inlet
connection
Check
valve
Secondary
circulation
pump
Swept
tee
Cold
supply
Secondary
return
Fig. 3: Secondary circulation connection