Description Of The Product; General Description; Operation Principle; Main Components - Heatrae Sadia Megaflo Eco 70i Manual

4. Description of the product

4.1 General description

This product is a purpose designed unvented water
heater. The unit has a stainless steel inner vessel,
which ensures an excellent standard of corrosion
resistance. The outer casing is a combination of resilient
thermoplastic mouldings and pre-painetd corrosion
proofed steel. All products are insulated with CFC free
polyurethane foam to give good heat loss protection.
The unit is supplied complete with all the necessary
safety and control devices needed to allow connection
to the cold water mains. All these components are
preset and should not be tampered with.

4.2 Operation principle

The unvented cylinder is used to heat and store
hot water for use in domestic or light commercial
applications.
Depending on the model the water can be heated
directly using Immersion heater(s) or indirectly through
a coil in the unit using an indirect heat source.
To provide pressure to the tap or shower an unvented
unit uses the incoming mains water pressure. To do this
the cylinder is sealed and not vented. However, when
the volume of water is heated it expands and without
any room for expansion could cause the cylinder to
rupture and fail. The cylinder requires no separate
expansion vessel to accommodate this expansion as
they incorporate an internal air gap.

4.3 Main components

See Figure 3 on page 9

4.4 Standard delivery

The delivery includes:
Cylinder incorporating factory fitted immersion
`
heater(s) and thermal controls and factory fitted
temperature and pressure relief valve
Instructions (inc
`
checklist & service record)
Cold water control pack
`
Combination valve (inc pressure reducing valve,
`
pressure relief valve, check valve and isolating
valve)
Tundish
`
2 port zone valve (indirect only)
`
Wiring centre (indirect only)
`
T&P relief valve insulation set
`
Drain valve
`
10
benchmark commissioning

4.5 Storage and Handling

If the unit is to be stored before installation it must be
placed upright on a secure, level surface and be in a
dry, frost free environment. The support surface must
be capable of supporting the packaged weight of the
unit, the packaged weights are displayed on the carton
label.
Please take care when handling a packaged cylinder.
The units are heavy and must only be moved manually
using safe working practices. The package weights
of each unit are displayed on the carton label. Once
removed the units can be lifted by screwing the lifting
handle provided onto the outlet boss, but again take
note of the unit weights when deciding on a safe lifting
method. DO NOT use the factory fitted T&P relief valve
to lift or manoeuvre the unit.