The Story
The EHC Neptune 200L Direct Unvented Stainless Steel Cylinder (NDIR200L) heats stored water entirely via its own twin 3kW Incoloy immersion elements, with no external boiler connection required. Constructed from Duplex stainless steel for corrosion resistance, it is designed for fast, safe, mains-pressure hot water delivery even in properties with lower incoming water pressure, making it a straightforward standalone hot water solution.
Controlled Service — Competent Person Required
Unvented cylinders are a controlled service under Building Regulation G3 (England & Wales), Technical Standard P3 (Scotland), or Building Regulation Part F (Northern Ireland), and must only be installed and commissioned by a competent, G3-qualified installer. The commissioning record must be completed and left with the householder for future reference.
No External Heat Source Required
Unlike an Indirect cylinder, this Direct model needs no connection to a boiler's primary circuit — both immersion elements independently heat the full 200L volume, making it a simple retrofit option where a wet heating boiler either isn't present or isn't intended to provide hot water.
Model-Specific Performance Data Not Published
EHC's current documentation confirms this cylinder's capacity (200L) and cased dimensions (1120mm height x 580mm diameter), but does not publish model-specific reheat time or empty/full weight figures for this exact 200L Direct SKU. Please contact EHC directly or request the current data sheet before specifying if these figures are required for a design calculation.
Duplex Stainless Steel Construction
The inner vessel is TIG welded from Duplex stainless steel and factory pressure-tested to 15 bar, giving strong corrosion resistance for long service life.
Twin Immersion Elements
Two independent 3kW Incoloy elements allow boost and economy heating modes, giving flexibility over how quickly and how much hot water is generated.
High-Performance in Low-Pressure Areas
Factory pre-adjusted controls are selected to combine high flow-rate performance with minimum pressure drop, helping the cylinder perform well even where incoming mains pressure is poor.
No Boiler Coil to Plumb
With no internal coil or primary circuit connection required, installation pipework is simpler than an equivalent Indirect cylinder.
Environmentally-Friendly Insulation
CFC- and HCFC-free polyurethane foam insulation reduces standing heat loss while avoiding ozone-depleting refrigerant gases in manufacture.
Rust-Resistant Steel Casing
The outer case is manufactured from rust-resistant steel, protecting the insulated inner vessel from external corrosion in typical domestic plant room or cupboard environments.
| Cylinder — Dimensions & Capacity | |
| Model / MPN | NDIR200L |
| Cylinder capacity | 200 litres |
| Cased height | 1120mm |
| Cased diameter | 580mm |
| Cylinder — Construction | |
| Construction | Duplex stainless steel, TIG welded |
| Factory pressure test | 15 bar |
| Insulation | CFC- and HCFC-free polyurethane foam |
| Regulatory status | Controlled service – England & Wales Building Reg. G3 / Scotland Technical Standard P3 / N. Ireland Building Reg. Part F |
| Cylinder — Pressure Specifications | |
| Max. inlet mains water pressure | 12 bar |
| Operating pressure | 3.0 bar |
| Expansion vessel charge pressure | 3.0 bar |
| Expansion valve opening pressure | 6.0 bar |
| Max. operating pressure | 7.0 bar |
| T&P relief valve opening | 7.0 bar |
| Cylinder — Immersion Heaters | |
| Immersion elements | 2 x 3kW, 240V, Incoloy (upper boost / lower economy) |
| Warranty | |
| Cylinder warranty | 2 years parts & labour from commissioning, subject to registration |
| Stainless steel inner vessel | 25-year guarantee (domestic installations) |
Details & Craftsmanship
Every detail has been carefully considered to bring you the perfect product.
Description
The EHC Neptune 200L Direct Unvented Stainless Steel Cylinder (NDIR200L) heats stored water entirely via its own twin 3kW Incoloy immersion elements, with no external boiler connection required. Constructed from Duplex stainless steel for corrosion resistance, it is designed for fast, safe, mains-pressure hot water delivery even in properties with lower incoming water pressure, making it a straightforward standalone hot water solution.
Controlled Service — Competent Person Required
Unvented cylinders are a controlled service under Building Regulation G3 (England & Wales), Technical Standard P3 (Scotland), or Building Regulation Part F (Northern Ireland), and must only be installed and commissioned by a competent, G3-qualified installer. The commissioning record must be completed and left with the householder for future reference.
No External Heat Source Required
Unlike an Indirect cylinder, this Direct model needs no connection to a boiler's primary circuit — both immersion elements independently heat the full 200L volume, making it a simple retrofit option where a wet heating boiler either isn't present or isn't intended to provide hot water.
Model-Specific Performance Data Not Published
EHC's current documentation confirms this cylinder's capacity (200L) and cased dimensions (1120mm height x 580mm diameter), but does not publish model-specific reheat time or empty/full weight figures for this exact 200L Direct SKU. Please contact EHC directly or request the current data sheet before specifying if these figures are required for a design calculation.
Duplex Stainless Steel Construction
The inner vessel is TIG welded from Duplex stainless steel and factory pressure-tested to 15 bar, giving strong corrosion resistance for long service life.
Twin Immersion Elements
Two independent 3kW Incoloy elements allow boost and economy heating modes, giving flexibility over how quickly and how much hot water is generated.
High-Performance in Low-Pressure Areas
Factory pre-adjusted controls are selected to combine high flow-rate performance with minimum pressure drop, helping the cylinder perform well even where incoming mains pressure is poor.
No Boiler Coil to Plumb
With no internal coil or primary circuit connection required, installation pipework is simpler than an equivalent Indirect cylinder.
Environmentally-Friendly Insulation
CFC- and HCFC-free polyurethane foam insulation reduces standing heat loss while avoiding ozone-depleting refrigerant gases in manufacture.
Rust-Resistant Steel Casing
The outer case is manufactured from rust-resistant steel, protecting the insulated inner vessel from external corrosion in typical domestic plant room or cupboard environments.
| Cylinder — Dimensions & Capacity | |
| Model / MPN | NDIR200L |
| Cylinder capacity | 200 litres |
| Cased height | 1120mm |
| Cased diameter | 580mm |
| Cylinder — Construction | |
| Construction | Duplex stainless steel, TIG welded |
| Factory pressure test | 15 bar |
| Insulation | CFC- and HCFC-free polyurethane foam |
| Regulatory status | Controlled service – England & Wales Building Reg. G3 / Scotland Technical Standard P3 / N. Ireland Building Reg. Part F |
| Cylinder — Pressure Specifications | |
| Max. inlet mains water pressure | 12 bar |
| Operating pressure | 3.0 bar |
| Expansion vessel charge pressure | 3.0 bar |
| Expansion valve opening pressure | 6.0 bar |
| Max. operating pressure | 7.0 bar |
| T&P relief valve opening | 7.0 bar |
| Cylinder — Immersion Heaters | |
| Immersion elements | 2 x 3kW, 240V, Incoloy (upper boost / lower economy) |
| Warranty | |
| Cylinder warranty | 2 years parts & labour from commissioning, subject to registration |
| Stainless steel inner vessel | 25-year guarantee (domestic installations) |
