Cylinder diameters are specified excluding port connections and insulation material. Only listed diameters are available.

For the total diameter of a cylinder including insulation, use the following formula; Insulation Depth x 2 + Cylinder Diameter = Total Diameter, or to find the replacement cylinder diameter , please refer to our online cylinder calculator.

Nominal 50mm insulation is recommended though custom depth can be specified between 35mm and 75mm

Uninsulated units are available upon request.

Material grade is important to consider especially in areas of hard or aggressive water quality, by designing a unit from thicker material can prolong the life of the unit.

This is one of the higher connections mounted on the side wall of the unit, and as there are a wide variety of connection sizes, its worth taking the time to read our Connection Size List before ordering a unit, if you are unsure then the simplest option is to specify the cylinder with 22mm or 28mm connections already attached to the unit, avoiding additional costs by having to use tank connectors.  All female connections are parallel BSP thread and taper fittings must not be used.

This can be specified rather than the use of an Essex flange and is generally positioned in the upper part of the cylinder and fitted with an internal air ingress prevention device. All compression fittings come with cap nut and olive, avoiding additional costs of tank connectors.

A secondary hot water return connection is generally specified on systems with long pipe runs to wash facilities.  Secondary return circuit provides hot water on demand and avoids wastage of cold water, eliminates dead legs in the system and reduces the risk of legionella. This system must be powered by a bronze circulating pump.

Boiler flow and return are connections that are fed from a heating appliance such as a boiler, wood burner or range type cooker. It is most important to specify 1" or 28mm connections and upwards for gravity flow and return circuits to ensure no airlocks occur within the internal coil of the cylinder (Please specify gravity flow and return in the additional information box if necessary).

The connection port is a ½" Female connection that allows for a screw in pocket that is supplied with the boiler control stat, usually specified as aqua control thermostat. This allows for more accurate control of the water temperature and is more efficient than the traditional strap on type control thermostat.

This is the valve positioned in the upper cold section of the unit and will require a 22mm hole for the ball valve connection to pass through. We can punch this hole as an option but generally no holes are punched in the cold section of the unit unless requested by the customer

The connection size for the mid entry immersion heater is 2¼" BSP female. An encoloy immersion is advised for use in hard water areas or for longevity. For particularly aggressive water conditions such as high chlorine or acidity, a titanium immersion heater is advised.

The connection size for the bottom entry immersion heater is 2¼" BSP female. An encoloy immersion is advised for use in hard water areas or for longevity. For particularly aggressive water conditions such as high chlorine or acidity, a titanium immersion heater is advised.

Direct flow and return connections were used with traditional solid fuel appliances in certain regions of the country and were specified with 1" Female or Male connections. They are generally not required anymore unless the cylinder is being replaced for use in an old system.

Self explanatory. Please avoid using a drain with a tapered thread or over packing with PTFE Tape.

This is the position specified looking down from above the cylinder as shown on the 'Plan View', 12 O'Clock being at the rear.

This is a screened warning overflow connector that allows for the expansion overflow, this requires a hole diameter of 27mm to pass through. We can punch this hole as an option but generally no holes are punched in the cold section of the unit unless requested by the customer