MEGAFLO Commercial 1000, Product Manual

Page: 17 / 40

Unvented Hot Water Cylinder
17
INST
ALLA
TION AND
COMMISSIONING (2)
Branches to drinking water outlets should be taken before the Pressure Relief Valve to avoid the
possibility of warm expanded water being drawn from the tap.
Drain valve
It is recommended that the drain valve (supplied) be incorporated into the cold water inlet system,
Fig 08. It is recommended that the outlet point of the drain pipe work be at least 1 metre below the
level of the heater (this can be achieved by attaching a hose pipe to the drain valve outlet spigot).
Outlet Pipe work
Ideally the pipe work from the Megaflo
Commercial
to the outlet fittings should be in 2” pipe,
smaller bore pipe can be used but it could impact on the performance of the unit. Small bore pipe
can also be used to suit some taps, but runs should be of minimum length. Pipe sizes may vary due
to system design.
Secondary Circulation
If a secondary circulation system is required it is recommended that it be connected to the Megaflo
Commercial
as shown in Figure 8. The secondary return pipe should be in 28mm pipe and incorporate
a check valve to prevent back flow. A suitable WRAS approved circulation pump will be required.
On large systems, due to the increase in system water content, it may be necessary to fit additional
expansion volume to the secondary system by fitting an external expansion vessel to the circuit. This
should be done if the capacity of the secondary circuit exceeds 10 litres.
De-stratification kits
The correct size of de-stratification kit must be used with your cylinder to ensure the volume can be
circulated in 1 hour. The pump instructions will need to be reviewed for information on the correct
setting. Please follow the installation schematic (fig 8) for guidance. When the system circulates it
needs to be specified by the installer to ensure water is not drawn off during the de-stratification
process. If a hot water demand is required during this period cold water may be discharged from
the hot outlet. It is recommended that a check valve be installed before the pump to stop any risk
of cold water draw off through the pump when it is not in use. For guidance on installation please
refer to figure 8.
Pipe capacities (copper)
22mm o/d = 0.38 litres per metre run (10 litres = 26m)
28mm o/d = 0.55 litres per metre run (10 litres = 18m)
35mm o/d = 0.83 litres per metre run (10 litres = 12m)
42mm o/d = 1.23 litres per meter run (10 litres = 8m)
Warnings
1. Under no circumstances should the factory fitted Temperature /Pressure Relief Valve be removed
other than by authorised Heatrae Sadia personnel. To do so will invalidate any guarantee or claim.
2. The Cold Water Combination Valve must be fitted to the mains water supply to the Megaflo
Commercial unit.
3. No control or safety valves should be tampered with or used for any other purposes.
4. Water may drip from the discharge pipe of the pressure relief device (Expansion Valve) and this
pipe must be left open to atmosphere. The discharge pipe should not be blocked or used for any
other purpose.
5. The tundish must be installed so that it is visible to the end user.
6. The tundish, drain valve and motorised valves must be installed away from any electrical
components.
7. No valve should be fitted between the 8 bar or 13 bar pressure relief valve and the Megaflo
Commercial unit.