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Xstream’s edge

The most important part of a hot water cylinder is the inner tank. It must perform under pressure at high temperatures and survive an extremely aggressive chemical environment. We use epoxy vinyl ester resin and glass in the construction of our inner tanks, thereby eliminating known causes of inner tank failures associated with traditional metal tanks. Non-ferrous materials (like those used by us) cannot corrode (a major reason for tank failures) nor can any galvanic reactions (where dissimilar materials are interconnected) occur - our tanks are totally corrosion free, no metal is used in the construction thereof.

Design features


For the installer

• All the fittings are positioned on one side of the tank for ease of connections and less pipe work.

• The tank is lightweight, easy to handle and install, less labour required.

• Drain- and safety valve factory fitted.

• Rear 22 mm connection port allows for easy interconnection of tanks.


For the home owner

• The tank can be manufactured in any colour in order to blend in with the environment.

• Can be installed either in- or outside.

• The tank is solar ready – a solar absorption panel can be connected at any future time.

• Low overnight heat losses as non-ferrous materials do not transfer heat, saving you on your electricity bill.

• Maximum hot water draw-off due to our efficient baffle/spreader, that prevents internal mixing of hot and incoming cold water.

• Second element position allows for improved energy efficiency control in that not all water is heated using electricity.

• 300 litre option available at lower stress points on roof structures – weight distributed over larger roof area.


Design aspects

Material selection is crucial as mentioned before. Our non-ferrous tanks are:

• Totally corrosion free – they will never rust.

• No galvanic reactions will occur in our tanks.

• Made from non-ferrous materials with uniform expansion rates (expansion caused by hot and cold cycles inside the inner tank) that totally eliminates the need for protective linings of any sort – (protective linings are used as protection against corrosion in metal tanks, but these can crack or delaminate in use, triggering corrosion in metal tanks).

• Ideal for in-series interconnections for increased volume.

• Designed so that, with both elements fitted a shortened reheating time will be possible for certain specialised requirements.

How the Mainstream Dual works

Our Mainstream dual tank range consists of closed vent tanks with a pressure rating of 400 kPa.


Referring to these tanks as “high pressure tanks” what is meant is that these are closed-vent tanks – as you open the hot water tap cold water basically pushes the hot water out, thus the tank can be positioned at a point lower than the draw-off point. In order to prevent the hot and cold water mixing inside the tank a diffuser is installed, keeping the incoming cold water at the bottom of the tank where the electric element is positioned in order to reheat the incoming cold water.


The tank is basically a storage tank of thermal energy (hot water). Once heated the tank’s purpose is to keep the water hot for later usage. Various heating sources can be used with the Xstream tank – electricity (element), solar panels or tubes or heat pumps.The tank is factory fitted with the necessary in- and outlet ports to accommodate these connections at any future time. The additional port and element cater for more specialised applications and allow for easy interconnection of tanks. This is the product for you if you want to do your own specialised design. Our interconnected tanks are widely used in vertical stack system applications.


It is therefore very important to weigh up all the options when replacing or installing a storage tank – the better it is insulated the longer the water inside the tank will remain hot and the less electricity will be used in maintaining the temperature inside the tank. 

Typical Xstream Mainstream Dual® interconned tanks for 300ℓ or 400ℓ capacity.

Various heating sources can be used with the Xstream Mainstream Dual tank as it is standard solar adaptable.

The Xstream Mainstream Dual range is factory fitted with: 

Xstream hard water incalloy element – good for any water condition (fitted with anode - increased element life-span).  

TSE 11 thermostat.

Cobra temperature and pressure safety valve (T&P).

Cobra drain valve fitted with lock nut.  

Other Accessories