Installation Instructions
9
4.15 External Expansion Vessel
This smaller tank is connected to the cold-water inlet side of the vessel. Mount the tank according to separate manufacturer’s
instructions provided with the external expansion vessel.
A suitable expansion vessel is supplied with Element cylinders with external expansion. Pre-charge the expansion vessel to match
the pressure relief valve (PRV) pressure setting. If kept at factory setting, 4.5 bar models should be pre-charged to 4.5 bar and 6.0
bar models should be pre-charged to 6.0 bar.
The expansion vessel should be tee’d off between the pressure relief valve and the cylinder (see figure 2) and should always be
positioned with the entry point at the bottom. Installation should always be by means of a standard T connector ensuring no other
valve is between this and the cylinder. Ensure that the expansion vessel is pre-charged to match the pressure relief valve (PRV)
pressure setting.
4.16 Recommended Installation Schematics
Figure 3:
Installation Schematic - External Expansion
Hot water draw off
Primary
return
Primary
flow
Discharge pipe
to safe position
Cold mains
1
7
6
2
5
4
3
1) Temperature and pressure relief valve
2) Motorised valve
3) Tundish
4) Expansion vessel
5) Drain valve
6) Comination valve including:
- Non return valve (check valve)
- Expansion relief valve (safety valve)
- Pressure reducing valve
- Strainer
- Balanced cold water draw-off
7) Isolating valve
