
- Incorporates built-in cold water storage (feed tank)
- Available to a bespoke specification for connection positioning and sizes
- Ideal solution for limited (or none) loft space
Combination Cylinders (also known as a Combi Cylinder) are designed as a space-saving unit by incorporating a built-in cold water storage tank at the top of the unit. This removes the need for a separate header tank, which is useful where there is little to no loft space. The external tank is pre-installed on the unit and connected with feed pipes reducing installation time.
As with many of our other units, we can manufacture a combination cylinder to a bespoke specification, allowing for the positioning of connections, connection sizes as well as additional heat sources such as solar, boiler and heat pump.
Although the unit sacrifices hot water storage volume for cold water storage volume, we can manufacture up to 600mm in diameter combination cylinders. This allows for a hot water storage volume sufficient for most domestic properties.
Size Guides
DIRECT COMBI SIZE GUIDE
Size | Hot | Cold |
---|---|---|
900×400 | 67 Litres | 16 Litres |
1050×400 | 91 Litres | 16 Litres |
1200×400 | 91 Litres | 32 Litres |
1500×400 | 114 Litres | 32 Litres |
1800×400 | 166 Litres | 32 Litres |
2000×400 | 210 Litres | 32 Litres |
900×450 | 85 Litres | 20 Litres |
1050×450 | 115 Litres | 20 Litres |
1200×450 | 115 Litres | 40 Litres |
1500×450 | 160 Litres | 40 Litres |
1800×450 | 210 Litres | 40 Litres |
2000×450 | 250 Litres | 40 Litres |
1500×500 | 180 Litres | 60 Litres |
1800×500 | 240 Litres | 60 Litres |
2000×500 | 260 Litres | 60 Litres |
1500×600 | 280 Litres | 80 Litres |
1800×600 | 320 Litres | 80 Litres |
2000×600 | 360 Litres | 80 Litres |
INDIRECT COMBI SIZE GUIDE
Size | Hot | Cold |
---|---|---|
900×400 | 67 Litres | 16 Litres |
1050×400 | 91 Litres | 16 Litres |
1200×400 | 91 Litres | 32 Litres |
1500×400 | 114 Litres | 32 Litres |
1800×400 | 166 Litres | 32 Litres |
2000×400 | 210 Litres | 32 Litres |
900×450 | 85 Litres | 20 Litres |
1050×450 | 115 Litres | 20 Litres |
1200×450 | 115 Litres | 40 Litres |
1500×450 | 160 Litres | 40 Litres |
1800×450 | 210 Litres | 40 Litres |
2000×450 | 250 Litres | 40 Litres |
1500×500 | 180 Litres | 60 Litres |
1800×500 | 240 Litres | 60 Litres |
2000×500 | 260 Litres | 60 Litres |
1500×600 | 280 Litres | 80 Litres |
1800×600 | 320 Litres | 80 Litres |
2000×600 | 360 Litres | 80 Litres |
Direct Combination Cylinder Specification
- 50mm Insulation
- 3/4″ Hot Draw Off
- 2 1/4″ Bottom Entry Immersion Heater Boss
- 1/2″ Drain
- Ball Valve & Float
- Aluminium Lid with Rolled Safety Edge.
Indirect Combination Cylinder Specification
- 50mm Insulation
- Boiler Coil with 3/4″ Male Connections
- 1″ Female Direct Connections
- 3/4″ Hot Draw Off
- 2 ¼″ Bottom Entry Immersion Heater Boss
- 1/2″ Drain
- Aluminium Lid with Rolled Safety Edge.
Example Specification

Like a standard vented system, a combination cylinder relies on gravity to supply hot water (potable) to a building’s outlets. The cold water cylinder (or tank) is located directly above the hot water tank. As a result of this, the generated ‘head’ of water pressure is relatively low.
An indirect combi cylinder, also known as an indirect cylinder or tank, utilizes an internal coil connected to a boiler or central heating system. This internal coil acts as the primary heat source to heat the water stored in the cylinder. In case of any issues with the primary heating system, there is a backup immersion heater available for heating purposes.
A fortic cylinder is an alternative name for a combi cylinder.