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EHC 300L Compact All-in-One Electric System Boiler - Ultimate Package
The EHC Compact All-In-One Electric System Boiler — 300L Ultimate Package is a factory-assembled, fully electric heating and hot water system combining a 12kW or 15kW electric system boiler with a 300-litre indirect unvented stainless steel cylinder on an 800×800mm footprint at 1,930mm tall. Supplied fully pre-plumbed and pre-wired with EHC Pro 4 magnetic filter, Adey MC1+ inhibitor and MC3+ cleaner, twin channel programmer, room thermostat and wiring centre. Suited to 5+ bedroom homes and larger properties. No flue, no gas supply, no annual gas safety check. 7–10 working day lead time. Free UK delivery.
12kW / 15kW
Boiler Output Options
300L
Cylinder Capacity
1930mm
Height
Pre-Plumbed
Factory Assembled
Grundfos
Pump
No Flue
Fully Electric
Range Overview — All Compact All-In-One Sizes
| Cylinder | Boiler Outputs | Height | Footprint | Filled Weight | Typical Home |
| 150L | 8kW / 10kW / 12kW / 15kW | 1081mm | 800×800mm | 211 kg | 1–2 bed flat / house |
| 170L | 10kW / 12kW / 15kW | 1209mm | 800×800mm | 235 kg | 2–3 bed home |
| 200L | 10kW / 12kW / 15kW | 1399mm | 800×800mm | 265 kg | 3–4 bed home |
| 250L | 12kW / 15kW | 1711mm | 800×800mm | 320 kg | 4–5 bed home |
| 300L | 12kW / 15kW | 1930mm | 800×800mm | 375 kg | 5+ bed home |
All models: 800×800mm footprint. 7–10 working day lead time. Free UK delivery.
What's in the Ultimate Package
Electric System Boiler — 8kW / 10kW / 12kW or 15kW (6-stage modulating, stainless steel heat exchanger, Grundfos pump, expansion vessel, auto-bypass, auto-air vent, digital display)
Indirect Unvented Stainless Steel Cylinder — 150L / 170L / 200L / 250L or 300L (polyurethane insulated, 2× zone valves, combination valve, T&P relief valve, tundish, DHW expansion vessel — fully pre-plumbed)
EHC Pro 4 Magnetic Filter — Protects heat exchanger and pump from magnetite and debris
Adey MC1+ System Inhibitor — Corrosion inhibitor for long-term system protection
Adey MC3+ System Cleaner — Pre-commission flush cleaner to remove installation debris
Twin Channel Programmer — Independent scheduling for heating circuit and hot water cylinder
Room Thermostat — Hard-wired room thermostat for accurate ambient temperature control
Wiring Centre — Central wiring hub for fast, clean and safe electrical connections
Copper Press Fittings — Pre-fitted — secure, no-solder leak-free connections
Note: radiators, radiator valves and system pipework are not included. Installation must be carried out by a G3 competent person (for the unvented cylinder) and a qualified electrician (for all electrical connections).
⚠ Installation Requirements: The unvented cylinder must be installed by a G3 competent person. All electrical connections must be made by a qualified electrician. A dedicated radial circuit with a suitably rated MCB is required for the boiler element. Minimum clearance: 150mm above unit for lid access; 450mm for internal access. Not suitable for gravity-fed (tank) hot water systems.
Key Features
100% Electric — No Flue, No Gas Pipework, No Annual Gas Safety Check
The Compact All-In-One is a fully electric system. No flue penetration, no combustion, no Gas Safe registration for the boiler work. Suitable for any property regardless of gas availability — ideal for off-grid locations, new builds subject to the Future Homes Standard, and properties converting from gas. Electric boilers are 100% efficient at point of use — every unit of electricity drawn converts directly into heat.
No flue requiredNo gas supply needed100% efficient
Boiler Output Choice: 12kW / 15kW — Match to Your Radiator Count
Available in 2 output options — 12kW / 15kW. Rule of thumb: add 1.5 kW for each radiator in the home when calculating the required output. The 15kW option suits the largest properties in this cylinder's target range. The boiler uses 6-stage modulating output — it does not run at full power continuously, modulating down to reduce electricity consumption during lower demand periods.
12kW / 15kW6-stage modulationMatch to rad count
Fully Pre-Plumbed and Pre-Wired — From Van to Done in Under 3 Hours
The Ultimate Package is supplied fully pre-plumbed and pre-wired. The cylinder arrives with zone valves, combination valve, T&P relief valve, tundish, DHW expansion vessel, wiring centre, programmer and room thermostat already connected and factory-assembled. EHC's headline claim is from van to done in under 3 hours for a qualified installer — significantly less than assembling and plumbing a boiler and cylinder separately.
Pre-plumbed + pre-wiredUnder 3 hours installUltimate Package
EHC Pro 4 Magnetic Filter — Protects the System From Day One
The EHC Pro 4 magnetic filter is included in the Ultimate Package — fitted inline to the system pipework to capture magnetite (iron oxide particles) and other ferrous debris before they reach the heat exchanger or Grundfos pump. Magnetite is the primary cause of premature pump failure and boiler heat exchanger blockage in electric and gas heating systems. Inclusion of the filter from the outset protects both the warranty and long-term performance.
EHC Pro 4 filterMagnetite removalProtects pump + HX
Adey MC1+ Inhibitor and MC3+ Cleaner — Professional System Treatment Included
The Ultimate Package includes both Adey MC1+ system inhibitor and Adey MC3+ system cleaner. MC3+ is used during commissioning to flush installation debris, flux residues and manufacturing oils from the new system. MC1+ is dosed into the system after flushing and provides long-term corrosion protection — a requirement of most boiler warranties. Having both chemicals in the package removes a common last-minute site sourcing issue.
Adey MC1+ inhibitorAdey MC3+ cleanerWarranty requirement
Twin Channel Programmer — Independent Heat and Hot Water Scheduling
The twin channel programmer controls the heating circuit and the hot water cylinder independently, allowing separate time schedules for each. In an S-plan configuration the homeowner can select heating only, hot water only, both, or neither — giving full control over energy use and comfort.
Twin channelS-plan readyIndependent heat + HW
Stainless Steel Unvented Cylinder with Polyurethane Insulation
The 300-litre indirect unvented cylinder is manufactured from stainless steel — corrosion-resistant and long-lasting. Polyurethane insulation minimises standing heat losses. Unvented design delivers mains-pressure hot water — suitable for power showers and modern high-flow fittings. Pre-fitted with 2× 22mm zone valves, combination valve, T&P relief valve, tundish and DHW expansion vessel.
Stainless steelMains pressure300L unvented
Grundfos Pump — Reliable Circulation, Quiet Operation
The system boiler incorporates a Grundfos circulation pump — the industry benchmark for reliability and efficiency in residential heating systems. Quiet operation makes it suitable for installations in kitchens, utility rooms and airing cupboards adjacent to living spaces.
Grundfos pumpQuiet operation
Built-In Diagnostics — Digital Display with Fault Code Readout
The system boiler features a digital display showing flow temperature, return temperature, system pressure and current kW output stage. The power stage indicator shows whether the boiler is operating at one-third, two-thirds or full output. In the event of a fault, diagnostic fault codes are displayed directly on the front panel — reducing call-out time for service engineers.
Digital displayLive kW stageFault codes
Technical Specifications
| Package | |
| SKU Codes | CAIO12/300IND-U, CAIO15/300IND-U |
| Cylinder Capacity | 300 litres (indirect unvented) |
| Boiler Output Options | 12kW / 15kW |
| Boiler Type | Electric system boiler — 6-stage modulating |
| Physical Dimensions | |
| Height | 1930 mm |
| Width | 800 mm |
| Depth | 800 mm |
| Empty Weight (unit) | approx. 75 kg |
| Filled Weight (full installation) | approx. 375 kg |
| Boiler | |
| Heat Exchanger | Stainless steel |
| Circulation Pump | Grundfos |
| Expansion Vessel | Built-in |
| Auto-Bypass | Built-in |
| Auto-Air Vent | Built-in |
| Temperature Range | 20–85°C (adjustable) |
| Display | Digital — flow temp, return temp, pressure, kW stage, fault codes |
| Cylinder | |
| Material | Stainless steel |
| Insulation | Polyurethane |
| Zone Valves | 2 × 22mm (pre-fitted) |
| Combination Valve | Pre-fitted |
| T&P Relief Valve | Pre-fitted |
| DHW Expansion Vessel | Pre-fitted |
| Tundish | Pre-fitted |
| Ultimate Package — Additional Inclusions | |
| Magnetic Filter | EHC Pro 4 |
| System Inhibitor | Adey MC1+ |
| System Cleaner | Adey MC3+ |
| Programmer | Twin channel (heat + hot water) |
| Room Thermostat | Included |
| Wiring Centre | Included |
| Supply | |
| Electrical Supply | 230V AC / single phase |
| Lead Time | 7–10 working days from order |
| Delivery | Free UK delivery (pallet) |
Frequently Asked Questions
Related Products
EHC Compact All-In-One 150L Ultimate
1–2 bed flat / house — 8kW/10kW/12kW/15kW
EHC Compact All-In-One 170L Ultimate
2–3 bed home — 10kW/12kW/15kW
EHC Compact All-In-One 200L Ultimate
3–4 bed home — 10kW/12kW/15kW
EHC Single Boiler Pack
Accessories and controls for standalone EHC boilers
Select Boiler & Cylinder
From $1,780.42
Original: $5,086.91
-65%EHC 300L Compact All-in-One Electric System Boiler - Ultimate Package—
$5,086.91
$1,780.42More Images
EHC 300L Compact All-in-One Electric System Boiler - Ultimate Package
The EHC Compact All-In-One Electric System Boiler — 300L Ultimate Package is a factory-assembled, fully electric heating and hot water system combining a 12kW or 15kW electric system boiler with a 300-litre indirect unvented stainless steel cylinder on an 800×800mm footprint at 1,930mm tall. Supplied fully pre-plumbed and pre-wired with EHC Pro 4 magnetic filter, Adey MC1+ inhibitor and MC3+ cleaner, twin channel programmer, room thermostat and wiring centre. Suited to 5+ bedroom homes and larger properties. No flue, no gas supply, no annual gas safety check. 7–10 working day lead time. Free UK delivery.
12kW / 15kW
Boiler Output Options
300L
Cylinder Capacity
1930mm
Height
Pre-Plumbed
Factory Assembled
Grundfos
Pump
No Flue
Fully Electric
Range Overview — All Compact All-In-One Sizes
| Cylinder | Boiler Outputs | Height | Footprint | Filled Weight | Typical Home |
| 150L | 8kW / 10kW / 12kW / 15kW | 1081mm | 800×800mm | 211 kg | 1–2 bed flat / house |
| 170L | 10kW / 12kW / 15kW | 1209mm | 800×800mm | 235 kg | 2–3 bed home |
| 200L | 10kW / 12kW / 15kW | 1399mm | 800×800mm | 265 kg | 3–4 bed home |
| 250L | 12kW / 15kW | 1711mm | 800×800mm | 320 kg | 4–5 bed home |
| 300L | 12kW / 15kW | 1930mm | 800×800mm | 375 kg | 5+ bed home |
All models: 800×800mm footprint. 7–10 working day lead time. Free UK delivery.
What's in the Ultimate Package
Electric System Boiler — 8kW / 10kW / 12kW or 15kW (6-stage modulating, stainless steel heat exchanger, Grundfos pump, expansion vessel, auto-bypass, auto-air vent, digital display)
Indirect Unvented Stainless Steel Cylinder — 150L / 170L / 200L / 250L or 300L (polyurethane insulated, 2× zone valves, combination valve, T&P relief valve, tundish, DHW expansion vessel — fully pre-plumbed)
EHC Pro 4 Magnetic Filter — Protects heat exchanger and pump from magnetite and debris
Adey MC1+ System Inhibitor — Corrosion inhibitor for long-term system protection
Adey MC3+ System Cleaner — Pre-commission flush cleaner to remove installation debris
Twin Channel Programmer — Independent scheduling for heating circuit and hot water cylinder
Room Thermostat — Hard-wired room thermostat for accurate ambient temperature control
Wiring Centre — Central wiring hub for fast, clean and safe electrical connections
Copper Press Fittings — Pre-fitted — secure, no-solder leak-free connections
Note: radiators, radiator valves and system pipework are not included. Installation must be carried out by a G3 competent person (for the unvented cylinder) and a qualified electrician (for all electrical connections).
⚠ Installation Requirements: The unvented cylinder must be installed by a G3 competent person. All electrical connections must be made by a qualified electrician. A dedicated radial circuit with a suitably rated MCB is required for the boiler element. Minimum clearance: 150mm above unit for lid access; 450mm for internal access. Not suitable for gravity-fed (tank) hot water systems.
Key Features
100% Electric — No Flue, No Gas Pipework, No Annual Gas Safety Check
The Compact All-In-One is a fully electric system. No flue penetration, no combustion, no Gas Safe registration for the boiler work. Suitable for any property regardless of gas availability — ideal for off-grid locations, new builds subject to the Future Homes Standard, and properties converting from gas. Electric boilers are 100% efficient at point of use — every unit of electricity drawn converts directly into heat.
No flue requiredNo gas supply needed100% efficient
Boiler Output Choice: 12kW / 15kW — Match to Your Radiator Count
Available in 2 output options — 12kW / 15kW. Rule of thumb: add 1.5 kW for each radiator in the home when calculating the required output. The 15kW option suits the largest properties in this cylinder's target range. The boiler uses 6-stage modulating output — it does not run at full power continuously, modulating down to reduce electricity consumption during lower demand periods.
12kW / 15kW6-stage modulationMatch to rad count
Fully Pre-Plumbed and Pre-Wired — From Van to Done in Under 3 Hours
The Ultimate Package is supplied fully pre-plumbed and pre-wired. The cylinder arrives with zone valves, combination valve, T&P relief valve, tundish, DHW expansion vessel, wiring centre, programmer and room thermostat already connected and factory-assembled. EHC's headline claim is from van to done in under 3 hours for a qualified installer — significantly less than assembling and plumbing a boiler and cylinder separately.
Pre-plumbed + pre-wiredUnder 3 hours installUltimate Package
EHC Pro 4 Magnetic Filter — Protects the System From Day One
The EHC Pro 4 magnetic filter is included in the Ultimate Package — fitted inline to the system pipework to capture magnetite (iron oxide particles) and other ferrous debris before they reach the heat exchanger or Grundfos pump. Magnetite is the primary cause of premature pump failure and boiler heat exchanger blockage in electric and gas heating systems. Inclusion of the filter from the outset protects both the warranty and long-term performance.
EHC Pro 4 filterMagnetite removalProtects pump + HX
Adey MC1+ Inhibitor and MC3+ Cleaner — Professional System Treatment Included
The Ultimate Package includes both Adey MC1+ system inhibitor and Adey MC3+ system cleaner. MC3+ is used during commissioning to flush installation debris, flux residues and manufacturing oils from the new system. MC1+ is dosed into the system after flushing and provides long-term corrosion protection — a requirement of most boiler warranties. Having both chemicals in the package removes a common last-minute site sourcing issue.
Adey MC1+ inhibitorAdey MC3+ cleanerWarranty requirement
Twin Channel Programmer — Independent Heat and Hot Water Scheduling
The twin channel programmer controls the heating circuit and the hot water cylinder independently, allowing separate time schedules for each. In an S-plan configuration the homeowner can select heating only, hot water only, both, or neither — giving full control over energy use and comfort.
Twin channelS-plan readyIndependent heat + HW
Stainless Steel Unvented Cylinder with Polyurethane Insulation
The 300-litre indirect unvented cylinder is manufactured from stainless steel — corrosion-resistant and long-lasting. Polyurethane insulation minimises standing heat losses. Unvented design delivers mains-pressure hot water — suitable for power showers and modern high-flow fittings. Pre-fitted with 2× 22mm zone valves, combination valve, T&P relief valve, tundish and DHW expansion vessel.
Stainless steelMains pressure300L unvented
Grundfos Pump — Reliable Circulation, Quiet Operation
The system boiler incorporates a Grundfos circulation pump — the industry benchmark for reliability and efficiency in residential heating systems. Quiet operation makes it suitable for installations in kitchens, utility rooms and airing cupboards adjacent to living spaces.
Grundfos pumpQuiet operation
Built-In Diagnostics — Digital Display with Fault Code Readout
The system boiler features a digital display showing flow temperature, return temperature, system pressure and current kW output stage. The power stage indicator shows whether the boiler is operating at one-third, two-thirds or full output. In the event of a fault, diagnostic fault codes are displayed directly on the front panel — reducing call-out time for service engineers.
Digital displayLive kW stageFault codes
Technical Specifications
| Package | |
| SKU Codes | CAIO12/300IND-U, CAIO15/300IND-U |
| Cylinder Capacity | 300 litres (indirect unvented) |
| Boiler Output Options | 12kW / 15kW |
| Boiler Type | Electric system boiler — 6-stage modulating |
| Physical Dimensions | |
| Height | 1930 mm |
| Width | 800 mm |
| Depth | 800 mm |
| Empty Weight (unit) | approx. 75 kg |
| Filled Weight (full installation) | approx. 375 kg |
| Boiler | |
| Heat Exchanger | Stainless steel |
| Circulation Pump | Grundfos |
| Expansion Vessel | Built-in |
| Auto-Bypass | Built-in |
| Auto-Air Vent | Built-in |
| Temperature Range | 20–85°C (adjustable) |
| Display | Digital — flow temp, return temp, pressure, kW stage, fault codes |
| Cylinder | |
| Material | Stainless steel |
| Insulation | Polyurethane |
| Zone Valves | 2 × 22mm (pre-fitted) |
| Combination Valve | Pre-fitted |
| T&P Relief Valve | Pre-fitted |
| DHW Expansion Vessel | Pre-fitted |
| Tundish | Pre-fitted |
| Ultimate Package — Additional Inclusions | |
| Magnetic Filter | EHC Pro 4 |
| System Inhibitor | Adey MC1+ |
| System Cleaner | Adey MC3+ |
| Programmer | Twin channel (heat + hot water) |
| Room Thermostat | Included |
| Wiring Centre | Included |
| Supply | |
| Electrical Supply | 230V AC / single phase |
| Lead Time | 7–10 working days from order |
| Delivery | Free UK delivery (pallet) |
Frequently Asked Questions
Related Products
EHC Compact All-In-One 150L Ultimate
1–2 bed flat / house — 8kW/10kW/12kW/15kW
EHC Compact All-In-One 170L Ultimate
2–3 bed home — 10kW/12kW/15kW
EHC Compact All-In-One 200L Ultimate
3–4 bed home — 10kW/12kW/15kW
EHC Single Boiler Pack
Accessories and controls for standalone EHC boilers
Product Information
Product Information
Shipping & Returns
Shipping & Returns
Description
The EHC Compact All-In-One Electric System Boiler — 300L Ultimate Package is a factory-assembled, fully electric heating and hot water system combining a 12kW or 15kW electric system boiler with a 300-litre indirect unvented stainless steel cylinder on an 800×800mm footprint at 1,930mm tall. Supplied fully pre-plumbed and pre-wired with EHC Pro 4 magnetic filter, Adey MC1+ inhibitor and MC3+ cleaner, twin channel programmer, room thermostat and wiring centre. Suited to 5+ bedroom homes and larger properties. No flue, no gas supply, no annual gas safety check. 7–10 working day lead time. Free UK delivery.
12kW / 15kW
Boiler Output Options
300L
Cylinder Capacity
1930mm
Height
Pre-Plumbed
Factory Assembled
Grundfos
Pump
No Flue
Fully Electric
Range Overview — All Compact All-In-One Sizes
| Cylinder | Boiler Outputs | Height | Footprint | Filled Weight | Typical Home |
| 150L | 8kW / 10kW / 12kW / 15kW | 1081mm | 800×800mm | 211 kg | 1–2 bed flat / house |
| 170L | 10kW / 12kW / 15kW | 1209mm | 800×800mm | 235 kg | 2–3 bed home |
| 200L | 10kW / 12kW / 15kW | 1399mm | 800×800mm | 265 kg | 3–4 bed home |
| 250L | 12kW / 15kW | 1711mm | 800×800mm | 320 kg | 4–5 bed home |
| 300L | 12kW / 15kW | 1930mm | 800×800mm | 375 kg | 5+ bed home |
All models: 800×800mm footprint. 7–10 working day lead time. Free UK delivery.
What's in the Ultimate Package
Electric System Boiler — 8kW / 10kW / 12kW or 15kW (6-stage modulating, stainless steel heat exchanger, Grundfos pump, expansion vessel, auto-bypass, auto-air vent, digital display)
Indirect Unvented Stainless Steel Cylinder — 150L / 170L / 200L / 250L or 300L (polyurethane insulated, 2× zone valves, combination valve, T&P relief valve, tundish, DHW expansion vessel — fully pre-plumbed)
EHC Pro 4 Magnetic Filter — Protects heat exchanger and pump from magnetite and debris
Adey MC1+ System Inhibitor — Corrosion inhibitor for long-term system protection
Adey MC3+ System Cleaner — Pre-commission flush cleaner to remove installation debris
Twin Channel Programmer — Independent scheduling for heating circuit and hot water cylinder
Room Thermostat — Hard-wired room thermostat for accurate ambient temperature control
Wiring Centre — Central wiring hub for fast, clean and safe electrical connections
Copper Press Fittings — Pre-fitted — secure, no-solder leak-free connections
Note: radiators, radiator valves and system pipework are not included. Installation must be carried out by a G3 competent person (for the unvented cylinder) and a qualified electrician (for all electrical connections).
⚠ Installation Requirements: The unvented cylinder must be installed by a G3 competent person. All electrical connections must be made by a qualified electrician. A dedicated radial circuit with a suitably rated MCB is required for the boiler element. Minimum clearance: 150mm above unit for lid access; 450mm for internal access. Not suitable for gravity-fed (tank) hot water systems.
Key Features
100% Electric — No Flue, No Gas Pipework, No Annual Gas Safety Check
The Compact All-In-One is a fully electric system. No flue penetration, no combustion, no Gas Safe registration for the boiler work. Suitable for any property regardless of gas availability — ideal for off-grid locations, new builds subject to the Future Homes Standard, and properties converting from gas. Electric boilers are 100% efficient at point of use — every unit of electricity drawn converts directly into heat.
No flue requiredNo gas supply needed100% efficient
Boiler Output Choice: 12kW / 15kW — Match to Your Radiator Count
Available in 2 output options — 12kW / 15kW. Rule of thumb: add 1.5 kW for each radiator in the home when calculating the required output. The 15kW option suits the largest properties in this cylinder's target range. The boiler uses 6-stage modulating output — it does not run at full power continuously, modulating down to reduce electricity consumption during lower demand periods.
12kW / 15kW6-stage modulationMatch to rad count
Fully Pre-Plumbed and Pre-Wired — From Van to Done in Under 3 Hours
The Ultimate Package is supplied fully pre-plumbed and pre-wired. The cylinder arrives with zone valves, combination valve, T&P relief valve, tundish, DHW expansion vessel, wiring centre, programmer and room thermostat already connected and factory-assembled. EHC's headline claim is from van to done in under 3 hours for a qualified installer — significantly less than assembling and plumbing a boiler and cylinder separately.
Pre-plumbed + pre-wiredUnder 3 hours installUltimate Package
EHC Pro 4 Magnetic Filter — Protects the System From Day One
The EHC Pro 4 magnetic filter is included in the Ultimate Package — fitted inline to the system pipework to capture magnetite (iron oxide particles) and other ferrous debris before they reach the heat exchanger or Grundfos pump. Magnetite is the primary cause of premature pump failure and boiler heat exchanger blockage in electric and gas heating systems. Inclusion of the filter from the outset protects both the warranty and long-term performance.
EHC Pro 4 filterMagnetite removalProtects pump + HX
Adey MC1+ Inhibitor and MC3+ Cleaner — Professional System Treatment Included
The Ultimate Package includes both Adey MC1+ system inhibitor and Adey MC3+ system cleaner. MC3+ is used during commissioning to flush installation debris, flux residues and manufacturing oils from the new system. MC1+ is dosed into the system after flushing and provides long-term corrosion protection — a requirement of most boiler warranties. Having both chemicals in the package removes a common last-minute site sourcing issue.
Adey MC1+ inhibitorAdey MC3+ cleanerWarranty requirement
Twin Channel Programmer — Independent Heat and Hot Water Scheduling
The twin channel programmer controls the heating circuit and the hot water cylinder independently, allowing separate time schedules for each. In an S-plan configuration the homeowner can select heating only, hot water only, both, or neither — giving full control over energy use and comfort.
Twin channelS-plan readyIndependent heat + HW
Stainless Steel Unvented Cylinder with Polyurethane Insulation
The 300-litre indirect unvented cylinder is manufactured from stainless steel — corrosion-resistant and long-lasting. Polyurethane insulation minimises standing heat losses. Unvented design delivers mains-pressure hot water — suitable for power showers and modern high-flow fittings. Pre-fitted with 2× 22mm zone valves, combination valve, T&P relief valve, tundish and DHW expansion vessel.
Stainless steelMains pressure300L unvented
Grundfos Pump — Reliable Circulation, Quiet Operation
The system boiler incorporates a Grundfos circulation pump — the industry benchmark for reliability and efficiency in residential heating systems. Quiet operation makes it suitable for installations in kitchens, utility rooms and airing cupboards adjacent to living spaces.
Grundfos pumpQuiet operation
Built-In Diagnostics — Digital Display with Fault Code Readout
The system boiler features a digital display showing flow temperature, return temperature, system pressure and current kW output stage. The power stage indicator shows whether the boiler is operating at one-third, two-thirds or full output. In the event of a fault, diagnostic fault codes are displayed directly on the front panel — reducing call-out time for service engineers.
Digital displayLive kW stageFault codes
Technical Specifications
| Package | |
| SKU Codes | CAIO12/300IND-U, CAIO15/300IND-U |
| Cylinder Capacity | 300 litres (indirect unvented) |
| Boiler Output Options | 12kW / 15kW |
| Boiler Type | Electric system boiler — 6-stage modulating |
| Physical Dimensions | |
| Height | 1930 mm |
| Width | 800 mm |
| Depth | 800 mm |
| Empty Weight (unit) | approx. 75 kg |
| Filled Weight (full installation) | approx. 375 kg |
| Boiler | |
| Heat Exchanger | Stainless steel |
| Circulation Pump | Grundfos |
| Expansion Vessel | Built-in |
| Auto-Bypass | Built-in |
| Auto-Air Vent | Built-in |
| Temperature Range | 20–85°C (adjustable) |
| Display | Digital — flow temp, return temp, pressure, kW stage, fault codes |
| Cylinder | |
| Material | Stainless steel |
| Insulation | Polyurethane |
| Zone Valves | 2 × 22mm (pre-fitted) |
| Combination Valve | Pre-fitted |
| T&P Relief Valve | Pre-fitted |
| DHW Expansion Vessel | Pre-fitted |
| Tundish | Pre-fitted |
| Ultimate Package — Additional Inclusions | |
| Magnetic Filter | EHC Pro 4 |
| System Inhibitor | Adey MC1+ |
| System Cleaner | Adey MC3+ |
| Programmer | Twin channel (heat + hot water) |
| Room Thermostat | Included |
| Wiring Centre | Included |
| Supply | |
| Electrical Supply | 230V AC / single phase |
| Lead Time | 7–10 working days from order |
| Delivery | Free UK delivery (pallet) |
Frequently Asked Questions
Related Products
EHC Compact All-In-One 150L Ultimate
1–2 bed flat / house — 8kW/10kW/12kW/15kW
EHC Compact All-In-One 170L Ultimate
2–3 bed home — 10kW/12kW/15kW
EHC Compact All-In-One 200L Ultimate
3–4 bed home — 10kW/12kW/15kW
EHC Single Boiler Pack
Accessories and controls for standalone EHC boilers
