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120L Indirect Slimline Internal Expansion Unvented Cylinder

Price: (Inc VAT)
£753.53 (inc VAT) £627.94 (exc VAT)
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Product Description

120L indirect slimline internal expansion unvented cylinder

These cylinders have a diameter of 475mm overall.

All Internal Expansion cylinders come with:
• 22mm threaded connections with compression fittings
• 90C/10 bar Temperature & Pressure relief valve
• Injected 50mm thick HCFC & CFC-free foam insulation
• Quiet & Long-life 3kW incoloy immersion heaters
• 25 year cylinder & 1 year parts transferrable warranty
• Full WRAS approval
• Comprehensive controls and unvented kit from leading suppliers

As water heats, it expands. In a vented system this heated water would cause the level in the header tank to rise, but would present no further problems. In an unvented setup, because no air enters or exits the system, it has to be accommodated for as part of G3 building regulations. Normally this would be solved by fitting an external expansion vessel (such as those supplied with our standard unvented range) into the cold inlet pipework. With these cylinders a “bubble” in the cylinder provides an internal chamber into which the water can expand, eliminating the need for an external vessel.

To create the stable air gap within the top of the cylinder, we have extended the hot draw off pipe further down into the cylinder. From there a moveable air to water composite plastic interface is fitted. This disc keeps an air bubble separate from the water being heated inside the cylinder. The baffle moves up and down with the expanding and contracting water level, allowing the unvented system to heat up safely.

In addition to improving SAP ratings when fitting into newbuild when compared to a standard unvented cylinder, the inerternal expansion unvented cylinders guarantee powerful performance through strong showers and fast-filling baths. Combine this with a 25 year warranty and you have a cylinder that keeps on giving.

The composite air to water baffle is manufactured from composite material fully compliant with BS6920 and is deemed by WRAS as suitable for internal thermal expansion. In addition to our own in-house test regime, the cylinder has been independently and successfully tested to WRAS 121117:1999.

These cylinders require a minimum of 1.50 bar mains pressure and 20 L/min flow rate to ensure that the cylinder meets its minimum capabilities. Higher mains pressure and flow rates will result in a higher performance from the cylinder.

All of our cylinders come with a 25-year cylinder and 1 year parts guarantee




Kit Supplied:


Technical Data:


 We usually have these in stock ready to ship next working day before midday but feel free to check stock levels by giving us a call on 0113 871 5 871.

Returns Policy:

Any faulty items are available for immediate replacement. Any orders incorrectly placed can be returned to the manufacturer with a re-stocking charge of 25% of the cylinder price or 35% if a collection is also required, assuming goods are in the same condition.

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