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Strom 14.4kW Single Phase Heat Only Electric Boiler SBSP15H 230V 62A
The Strom 14.4 kW Single Phase Heat Only Electric Boiler (SBSP15H) is the highest-output model in the Strom single-phase heat-only range, designed to serve larger homes or properties where a separate indirect hot water cylinder already handles domestic hot water. At just 520 × 235 × 120 mm and drawing 62 A from a standard 230 V single-phase supply, it delivers 14.4 kW of continuous central heating output from a unit smaller than most gas boilers. The heat-only format means there is no integrated pump or expansion vessel — these are fitted externally, giving the installer complete control over component selection and positioning. No flue is required, zero CO or CO₂ emissions at point of use, and with almost no moving parts the boiler runs near-silently throughout its service life. Compatible with solar PV diversion, underfloor heating and all standard S-plan and Y-plan central heating systems. LED digital display. 2-year manufacturer’s warranty with registration within 45 days (1 year without).
14.4 kW
Heat output
230V 1 ph
Single phase
62A
Current draw
No flue
Zero CO emissions
20– 80°C
Flow temp range
2 yr
Warranty (registered)
⚠ Professional installation required: This boiler draws 62 A at 230 V and must be connected to the mains by a competent electrician certified to BS 7671 (18th Edition). Plumbing installation must be completed by a qualified and certified heating engineer. Strom Limited accepts no liability for installations carried out by unqualified persons.
ℹ Register within 45 days for the full 2-year warranty: The standard out-of-box warranty is 1 year. Register at stromltd.com/guarantee within 45 days of purchase using the registration card supplied in the box to extend this to 2 years. Only the legal owner of the building can register and make a warranty claim. Keep your merchant invoice as proof of purchase.
ℹ External components required — not included: The heat-only boiler does not include a pump, expansion vessel or filling loop. These must be installed externally by a qualified engineer. An external bypass valve must also be fitted to allow system circulation when all TRVs are closed. Flexi hoses are strongly recommended on the flow and return connections.
What’s in the Box
Strom SBSP15H Boiler Unit
14.4 kW wall-mounted heat-only electric boiler. Built-in auto air vent, LED digital display and 15 mm compression PRV connection. Upright installation only.
Wall Fixings and Mounting Guide
All fixings for wall installation. Wall must support the boiler’s weight when filled. Boiler must be mounted vertically — other orientations void the warranty.
Installation Manual
Strom installation and operating instructions: system design, electrical connection, commissioning and maintenance requirements.
Warranty Registration Card
Register at stromltd.com/guarantee within 45 days of purchase to activate the 2-year warranty. Keep your invoice as proof of purchase.
Heat Only vs System Boiler — Which Do You Need?
| Heat Only (this boiler) | System Boiler | |
|---|---|---|
| Integrated pump | ✘ External (installer’s choice) | ✓ Built-in |
| Integrated expansion vessel | ✘ External (installer’s choice) | ✓ Built-in |
| Domestic hot water | ✘ Indirect cylinder required | ✘ Indirect cylinder required |
| Physical size | Smallest (520 × 235 × 120mm) | Larger (includes pump and vessel) |
| Best for | Existing systems with external components; tight spaces; maximum flexibility | New installations wanting all-in-one unit |
| Bypass valve required | ✓ Yes (external) | ✓ Yes (external) |
Both types require an indirect hot water cylinder for domestic hot water. Choose the heat-only format when an external pump and vessel are already in place, when space is extremely tight, or when the installer needs to specify their own pump grade.
External Components Required — Not Included
The heat-only format contains only the heating element, controls and safety devices. Your heating engineer will need to supply and fit the following:
Circulator Pump (required)
Circulates heated water around the system. Use a high-efficiency variable-speed pump. Full bore isolation valves only on flow and return — standard ball valves restrict flow and reduce performance.
Expansion Vessel (required)
Accommodates thermal expansion of heating water. Size to suit total system volume. Must be pre-charged to match system fill pressure before commissioning.
Bypass Valve (required)
Allows system water to circulate when all TRVs are fully closed. Prevents the boiler from overheating under low-demand conditions.
Filling Loop (required)
For pressurising the system to 1.0 – 1.5 bar at commissioning. Must be removed after filling per Water Supply (Water Fittings) Regulations.
Full Bore Isolation Valves (strongly recommended)
Fit on flow and return to isolate the boiler for maintenance without draining the whole system. Standard ball valves create flow restrictions; full bore valves do not.
Flexi Hoses (strongly recommended)
Strom recommends flexi hoses on the 3/4" flow and return connections. Overtightening rigid compression fittings can damage boiler internals — this is explicitly excluded from warranty cover.
Key Features
14.4 kW — Maximum Single-Phase Heat-Only Output
This is the highest output available from a 230 V single-phase heat-only electric boiler. A typical UK three-bedroom semi-detached has a design heat load of 6 – 9 kW; larger or poorly insulated properties can reach 12 – 14 kW. At 14.4 kW this boiler covers the full single-phase residential range. Properties needing more than 14.4 kW would require a three-phase supply.
14.4 kW230V single phase62A / min 63A breaker
Smallest Possible Unit — 520 × 235 × 120 mm
Stripping out the pump and vessel leaves a unit roughly the size of a large hardback book. The 120 mm depth is less than many kitchen cupboard shelves. The SBSP15H fits inside a kitchen cabinet, on an airing cupboard wall, in a utility room corner, in a garage, or in any plant room with minimal clear wall space. It must be mounted upright on a vertical wall — any other orientation invalidates the warranty.
520 × 235 × 120mmUpright wall mount only
No Flue, No Gas, No Emissions at Point of Use
With no burner, no combustion and no exhaust gas, no flue is required and there is zero risk of carbon monoxide. This eliminates the structural and regulatory complexity of gas or oil installation and makes the boiler suitable for any indoor location without ventilation requirements. Ideal for off-gas-grid properties, flats where fluing is impractical, and heritage or listed buildings where external penetrations are restricted.
No flueZero CO riskOff-gas-grid compatible
LED Digital Display — External Thermostat Compatible
The LED digital display shows flow temperature and system status. Temperature is adjustable across the full 20 – 80°C range. An external room thermostat or time clock can be wired in for zone control and scheduling — compatible with standard S-plan, Y-plan and wiring centre configurations.
LED display20–80°CExternal thermostat compatible
Solar PV Diversion and Underfloor Heating Compatible
Works with solar PV diversion devices (myenergi Eddi, iBoost, etc.) to use surplus solar generation for space heating instead of exporting at low SEG rates. The 20 – 80°C flow temperature range also makes it compatible with wet underfloor heating systems, which typically operate at 35 – 55°C (use manifold mixing valves to maintain correct UFH temperatures).
Solar PV diversionUnderfloor heating20–80°C range
Near-Silent Operation — Minimal Moving Parts
No burner, no fan, no heat exchanger, no internal pump. The heating element operates in complete silence. The only sound in the system comes from the external pump, which the installer can position to minimise noise transmission. Minimal moving parts means fewer wear components, lower servicing requirements and high long-term reliability.
No burner or fanNear-silentLow servicing requirement
Built-in Auto Air Vent and PRV Connection
An automatic air vent is built into the boiler. If used with an indirect cylinder, an additional auto air vent should be fitted near the cylinder coil. The 15 mm compression PRV connection accepts the pressure relief valve, which must be piped to a safe discharge point. A system drain point should be fitted at the lowest point of the circuit to allow draining without discharging through the PRV.
Built-in auto air vent15mm compression PRV connection
All Standard Heating Configurations Supported
Compatible with S-plan, Y-plan, fully pumped and gravity-assisted systems. Supplies a heating circuit and can feed an indirect hot water cylinder via a motorised valve or cylinder thermostat. System design to BS EN 12828 / 12831. Water treatment to BS EN 7593 with a proprietary inhibitor to protect the heating element and pipework.
S-plan and Y-planSealed systemIndirect cylinder
Installation Quick Reference
Electrical supply
230 V single phase. 62 A draw. Min 63 A circuit breaker. Min 10 mm² cable. Linked isolator with min 3 mm contact gap in every pole. Cable entry at top right panel.
Electrical certification
Connection by a competent electrician to BS 7671 (18th Edition). System must be earthed before any current is applied.
Plumbing certification
By a qualified and certified heating engineer. Design to BS EN 12828, 12831 and 14336. Water treatment to BS EN 7593.
System pressure
Fill to 1.0 – 1.5 bar. Fill slowly, vent all manual release valves to purge air. Remove filling loop after commissioning.
Pipework connections
3/4" male (22 mm pipe). Full bore isolation valves on flow and return. Flexi hoses strongly recommended. Do not overtighten rigid fittings.
Mounting and location
Upright on vertical wall only — other orientations void warranty. Wall must support boiler weight when filled. Allow access for front panel removal. Avoid frost-risk locations.
Technical Specifications
| Boiler Performance | |
| Model | SBSP15H |
| Heat output | 14.4 kW |
| ERP rating (heating) | D |
| Flow temperature range | 20 – 80°C (adjustable) |
| Heating pressure range | 0.5 – 1.5 bar |
| Electrical | |
| Power supply | 230 V, single phase |
| Current draw | 62 A |
| Minimum circuit breaker | 63 A |
| Minimum cable size | 10 mm² |
| Connections | |
| Flow and return | 3/4" Male (22 mm pipe) |
| PRV connection | 15 mm compression |
| Physical | |
| Dimensions (H × W × D) | 520 × 235 × 120 mm |
| Mounting | Wall-mounted, upright only (warranty void otherwise) |
| Features | |
| Display | LED digital display |
| Built-in auto air vent | Yes |
| Integrated pump | No — external pump required |
| Integrated expansion vessel | No — external expansion vessel required |
| Flue required | No |
| Emissions at point of use | Zero (no combustion) |
| Compatibility | |
| Heating systems | S-plan, Y-plan, sealed system, fully pumped |
| Domestic hot water | Via indirect cylinder (sold separately) |
| Solar PV diversion | Compatible |
| Underfloor heating | Compatible |
| Standards | |
| Heating design | BS EN 12828, BS EN 12831, BS EN 14336 |
| Electrical | BS 7671 (18th Edition IEE Wiring Regulations) |
| Water treatment | BS EN 7593 |
| Warranty | |
| Standard warranty | 1 year (without registration) |
| Extended warranty | 2 years (register within 45 days at stromltd.com/guarantee) |
| Warranty holder | Legal owner of building only |
| Box Contents | |
| Included | Boiler unit, wall fixings, mounting guide, installation manual, registration card |
| EAN barcode | 5060438333571 |
Frequently Asked Questions
Related Products
Strom 14.4kW Single Phase System Boiler
Same output with integrated pump and expansion vessel
Indirect Unvented Hot Water Cylinder
Required for domestic hot water with this heat-only boiler
Grundfos UPM3 AUTO 25-70 Circulator Pump
High-efficiency variable-speed pump for the external circuit
myenergi Eddi Solar PV Diverter
Diverts surplus solar generation to space heating
Product Information
Product Information
Shipping & Returns
Shipping & Returns
Strom 14.4kW Single Phase Heat Only Electric Boiler SBSP15H 230V 62A
Strom 14.4kW Single Phase Heat Only Electric Boiler SBSP15H 230V 62A
The Strom 14.4 kW Single Phase Heat Only Electric Boiler (SBSP15H) is the highest-output model in the Strom single-phase heat-only range, designed to serve larger homes or properties where a separate indirect hot water cylinder already handles domestic hot water. At just 520 × 235 × 120 mm and drawing 62 A from a standard 230 V single-phase supply, it delivers 14.4 kW of continuous central heating output from a unit smaller than most gas boilers. The heat-only format means there is no integrated pump or expansion vessel — these are fitted externally, giving the installer complete control over component selection and positioning. No flue is required, zero CO or CO₂ emissions at point of use, and with almost no moving parts the boiler runs near-silently throughout its service life. Compatible with solar PV diversion, underfloor heating and all standard S-plan and Y-plan central heating systems. LED digital display. 2-year manufacturer’s warranty with registration within 45 days (1 year without).
14.4 kW
Heat output
230V 1 ph
Single phase
62A
Current draw
No flue
Zero CO emissions
20– 80°C
Flow temp range
2 yr
Warranty (registered)
⚠ Professional installation required: This boiler draws 62 A at 230 V and must be connected to the mains by a competent electrician certified to BS 7671 (18th Edition). Plumbing installation must be completed by a qualified and certified heating engineer. Strom Limited accepts no liability for installations carried out by unqualified persons.
ℹ Register within 45 days for the full 2-year warranty: The standard out-of-box warranty is 1 year. Register at stromltd.com/guarantee within 45 days of purchase using the registration card supplied in the box to extend this to 2 years. Only the legal owner of the building can register and make a warranty claim. Keep your merchant invoice as proof of purchase.
ℹ External components required — not included: The heat-only boiler does not include a pump, expansion vessel or filling loop. These must be installed externally by a qualified engineer. An external bypass valve must also be fitted to allow system circulation when all TRVs are closed. Flexi hoses are strongly recommended on the flow and return connections.
What’s in the Box
Strom SBSP15H Boiler Unit
14.4 kW wall-mounted heat-only electric boiler. Built-in auto air vent, LED digital display and 15 mm compression PRV connection. Upright installation only.
Wall Fixings and Mounting Guide
All fixings for wall installation. Wall must support the boiler’s weight when filled. Boiler must be mounted vertically — other orientations void the warranty.
Installation Manual
Strom installation and operating instructions: system design, electrical connection, commissioning and maintenance requirements.
Warranty Registration Card
Register at stromltd.com/guarantee within 45 days of purchase to activate the 2-year warranty. Keep your invoice as proof of purchase.
Heat Only vs System Boiler — Which Do You Need?
| Heat Only (this boiler) | System Boiler | |
|---|---|---|
| Integrated pump | ✘ External (installer’s choice) | ✓ Built-in |
| Integrated expansion vessel | ✘ External (installer’s choice) | ✓ Built-in |
| Domestic hot water | ✘ Indirect cylinder required | ✘ Indirect cylinder required |
| Physical size | Smallest (520 × 235 × 120mm) | Larger (includes pump and vessel) |
| Best for | Existing systems with external components; tight spaces; maximum flexibility | New installations wanting all-in-one unit |
| Bypass valve required | ✓ Yes (external) | ✓ Yes (external) |
Both types require an indirect hot water cylinder for domestic hot water. Choose the heat-only format when an external pump and vessel are already in place, when space is extremely tight, or when the installer needs to specify their own pump grade.
External Components Required — Not Included
The heat-only format contains only the heating element, controls and safety devices. Your heating engineer will need to supply and fit the following:
Circulator Pump (required)
Circulates heated water around the system. Use a high-efficiency variable-speed pump. Full bore isolation valves only on flow and return — standard ball valves restrict flow and reduce performance.
Expansion Vessel (required)
Accommodates thermal expansion of heating water. Size to suit total system volume. Must be pre-charged to match system fill pressure before commissioning.
Bypass Valve (required)
Allows system water to circulate when all TRVs are fully closed. Prevents the boiler from overheating under low-demand conditions.
Filling Loop (required)
For pressurising the system to 1.0 – 1.5 bar at commissioning. Must be removed after filling per Water Supply (Water Fittings) Regulations.
Full Bore Isolation Valves (strongly recommended)
Fit on flow and return to isolate the boiler for maintenance without draining the whole system. Standard ball valves create flow restrictions; full bore valves do not.
Flexi Hoses (strongly recommended)
Strom recommends flexi hoses on the 3/4" flow and return connections. Overtightening rigid compression fittings can damage boiler internals — this is explicitly excluded from warranty cover.
Key Features
14.4 kW — Maximum Single-Phase Heat-Only Output
This is the highest output available from a 230 V single-phase heat-only electric boiler. A typical UK three-bedroom semi-detached has a design heat load of 6 – 9 kW; larger or poorly insulated properties can reach 12 – 14 kW. At 14.4 kW this boiler covers the full single-phase residential range. Properties needing more than 14.4 kW would require a three-phase supply.
14.4 kW230V single phase62A / min 63A breaker
Smallest Possible Unit — 520 × 235 × 120 mm
Stripping out the pump and vessel leaves a unit roughly the size of a large hardback book. The 120 mm depth is less than many kitchen cupboard shelves. The SBSP15H fits inside a kitchen cabinet, on an airing cupboard wall, in a utility room corner, in a garage, or in any plant room with minimal clear wall space. It must be mounted upright on a vertical wall — any other orientation invalidates the warranty.
520 × 235 × 120mmUpright wall mount only
No Flue, No Gas, No Emissions at Point of Use
With no burner, no combustion and no exhaust gas, no flue is required and there is zero risk of carbon monoxide. This eliminates the structural and regulatory complexity of gas or oil installation and makes the boiler suitable for any indoor location without ventilation requirements. Ideal for off-gas-grid properties, flats where fluing is impractical, and heritage or listed buildings where external penetrations are restricted.
No flueZero CO riskOff-gas-grid compatible
LED Digital Display — External Thermostat Compatible
The LED digital display shows flow temperature and system status. Temperature is adjustable across the full 20 – 80°C range. An external room thermostat or time clock can be wired in for zone control and scheduling — compatible with standard S-plan, Y-plan and wiring centre configurations.
LED display20–80°CExternal thermostat compatible
Solar PV Diversion and Underfloor Heating Compatible
Works with solar PV diversion devices (myenergi Eddi, iBoost, etc.) to use surplus solar generation for space heating instead of exporting at low SEG rates. The 20 – 80°C flow temperature range also makes it compatible with wet underfloor heating systems, which typically operate at 35 – 55°C (use manifold mixing valves to maintain correct UFH temperatures).
Solar PV diversionUnderfloor heating20–80°C range
Near-Silent Operation — Minimal Moving Parts
No burner, no fan, no heat exchanger, no internal pump. The heating element operates in complete silence. The only sound in the system comes from the external pump, which the installer can position to minimise noise transmission. Minimal moving parts means fewer wear components, lower servicing requirements and high long-term reliability.
No burner or fanNear-silentLow servicing requirement
Built-in Auto Air Vent and PRV Connection
An automatic air vent is built into the boiler. If used with an indirect cylinder, an additional auto air vent should be fitted near the cylinder coil. The 15 mm compression PRV connection accepts the pressure relief valve, which must be piped to a safe discharge point. A system drain point should be fitted at the lowest point of the circuit to allow draining without discharging through the PRV.
Built-in auto air vent15mm compression PRV connection
All Standard Heating Configurations Supported
Compatible with S-plan, Y-plan, fully pumped and gravity-assisted systems. Supplies a heating circuit and can feed an indirect hot water cylinder via a motorised valve or cylinder thermostat. System design to BS EN 12828 / 12831. Water treatment to BS EN 7593 with a proprietary inhibitor to protect the heating element and pipework.
S-plan and Y-planSealed systemIndirect cylinder
Installation Quick Reference
Electrical supply
230 V single phase. 62 A draw. Min 63 A circuit breaker. Min 10 mm² cable. Linked isolator with min 3 mm contact gap in every pole. Cable entry at top right panel.
Electrical certification
Connection by a competent electrician to BS 7671 (18th Edition). System must be earthed before any current is applied.
Plumbing certification
By a qualified and certified heating engineer. Design to BS EN 12828, 12831 and 14336. Water treatment to BS EN 7593.
System pressure
Fill to 1.0 – 1.5 bar. Fill slowly, vent all manual release valves to purge air. Remove filling loop after commissioning.
Pipework connections
3/4" male (22 mm pipe). Full bore isolation valves on flow and return. Flexi hoses strongly recommended. Do not overtighten rigid fittings.
Mounting and location
Upright on vertical wall only — other orientations void warranty. Wall must support boiler weight when filled. Allow access for front panel removal. Avoid frost-risk locations.
Technical Specifications
| Boiler Performance | |
| Model | SBSP15H |
| Heat output | 14.4 kW |
| ERP rating (heating) | D |
| Flow temperature range | 20 – 80°C (adjustable) |
| Heating pressure range | 0.5 – 1.5 bar |
| Electrical | |
| Power supply | 230 V, single phase |
| Current draw | 62 A |
| Minimum circuit breaker | 63 A |
| Minimum cable size | 10 mm² |
| Connections | |
| Flow and return | 3/4" Male (22 mm pipe) |
| PRV connection | 15 mm compression |
| Physical | |
| Dimensions (H × W × D) | 520 × 235 × 120 mm |
| Mounting | Wall-mounted, upright only (warranty void otherwise) |
| Features | |
| Display | LED digital display |
| Built-in auto air vent | Yes |
| Integrated pump | No — external pump required |
| Integrated expansion vessel | No — external expansion vessel required |
| Flue required | No |
| Emissions at point of use | Zero (no combustion) |
| Compatibility | |
| Heating systems | S-plan, Y-plan, sealed system, fully pumped |
| Domestic hot water | Via indirect cylinder (sold separately) |
| Solar PV diversion | Compatible |
| Underfloor heating | Compatible |
| Standards | |
| Heating design | BS EN 12828, BS EN 12831, BS EN 14336 |
| Electrical | BS 7671 (18th Edition IEE Wiring Regulations) |
| Water treatment | BS EN 7593 |
| Warranty | |
| Standard warranty | 1 year (without registration) |
| Extended warranty | 2 years (register within 45 days at stromltd.com/guarantee) |
| Warranty holder | Legal owner of building only |
| Box Contents | |
| Included | Boiler unit, wall fixings, mounting guide, installation manual, registration card |
| EAN barcode | 5060438333571 |
Frequently Asked Questions
Related Products
Strom 14.4kW Single Phase System Boiler
Same output with integrated pump and expansion vessel
Indirect Unvented Hot Water Cylinder
Required for domestic hot water with this heat-only boiler
Grundfos UPM3 AUTO 25-70 Circulator Pump
High-efficiency variable-speed pump for the external circuit
myenergi Eddi Solar PV Diverter
Diverts surplus solar generation to space heating
$1,018.73
Strom 14.4kW Single Phase Heat Only Electric Boiler SBSP15H 230V 62A—
$1,018.73
Product Information
Product Information
Shipping & Returns
Shipping & Returns
Description
The Strom 14.4 kW Single Phase Heat Only Electric Boiler (SBSP15H) is the highest-output model in the Strom single-phase heat-only range, designed to serve larger homes or properties where a separate indirect hot water cylinder already handles domestic hot water. At just 520 × 235 × 120 mm and drawing 62 A from a standard 230 V single-phase supply, it delivers 14.4 kW of continuous central heating output from a unit smaller than most gas boilers. The heat-only format means there is no integrated pump or expansion vessel — these are fitted externally, giving the installer complete control over component selection and positioning. No flue is required, zero CO or CO₂ emissions at point of use, and with almost no moving parts the boiler runs near-silently throughout its service life. Compatible with solar PV diversion, underfloor heating and all standard S-plan and Y-plan central heating systems. LED digital display. 2-year manufacturer’s warranty with registration within 45 days (1 year without).
14.4 kW
Heat output
230V 1 ph
Single phase
62A
Current draw
No flue
Zero CO emissions
20– 80°C
Flow temp range
2 yr
Warranty (registered)
⚠ Professional installation required: This boiler draws 62 A at 230 V and must be connected to the mains by a competent electrician certified to BS 7671 (18th Edition). Plumbing installation must be completed by a qualified and certified heating engineer. Strom Limited accepts no liability for installations carried out by unqualified persons.
ℹ Register within 45 days for the full 2-year warranty: The standard out-of-box warranty is 1 year. Register at stromltd.com/guarantee within 45 days of purchase using the registration card supplied in the box to extend this to 2 years. Only the legal owner of the building can register and make a warranty claim. Keep your merchant invoice as proof of purchase.
ℹ External components required — not included: The heat-only boiler does not include a pump, expansion vessel or filling loop. These must be installed externally by a qualified engineer. An external bypass valve must also be fitted to allow system circulation when all TRVs are closed. Flexi hoses are strongly recommended on the flow and return connections.
What’s in the Box
Strom SBSP15H Boiler Unit
14.4 kW wall-mounted heat-only electric boiler. Built-in auto air vent, LED digital display and 15 mm compression PRV connection. Upright installation only.
Wall Fixings and Mounting Guide
All fixings for wall installation. Wall must support the boiler’s weight when filled. Boiler must be mounted vertically — other orientations void the warranty.
Installation Manual
Strom installation and operating instructions: system design, electrical connection, commissioning and maintenance requirements.
Warranty Registration Card
Register at stromltd.com/guarantee within 45 days of purchase to activate the 2-year warranty. Keep your invoice as proof of purchase.
Heat Only vs System Boiler — Which Do You Need?
| Heat Only (this boiler) | System Boiler | |
|---|---|---|
| Integrated pump | ✘ External (installer’s choice) | ✓ Built-in |
| Integrated expansion vessel | ✘ External (installer’s choice) | ✓ Built-in |
| Domestic hot water | ✘ Indirect cylinder required | ✘ Indirect cylinder required |
| Physical size | Smallest (520 × 235 × 120mm) | Larger (includes pump and vessel) |
| Best for | Existing systems with external components; tight spaces; maximum flexibility | New installations wanting all-in-one unit |
| Bypass valve required | ✓ Yes (external) | ✓ Yes (external) |
Both types require an indirect hot water cylinder for domestic hot water. Choose the heat-only format when an external pump and vessel are already in place, when space is extremely tight, or when the installer needs to specify their own pump grade.
External Components Required — Not Included
The heat-only format contains only the heating element, controls and safety devices. Your heating engineer will need to supply and fit the following:
Circulator Pump (required)
Circulates heated water around the system. Use a high-efficiency variable-speed pump. Full bore isolation valves only on flow and return — standard ball valves restrict flow and reduce performance.
Expansion Vessel (required)
Accommodates thermal expansion of heating water. Size to suit total system volume. Must be pre-charged to match system fill pressure before commissioning.
Bypass Valve (required)
Allows system water to circulate when all TRVs are fully closed. Prevents the boiler from overheating under low-demand conditions.
Filling Loop (required)
For pressurising the system to 1.0 – 1.5 bar at commissioning. Must be removed after filling per Water Supply (Water Fittings) Regulations.
Full Bore Isolation Valves (strongly recommended)
Fit on flow and return to isolate the boiler for maintenance without draining the whole system. Standard ball valves create flow restrictions; full bore valves do not.
Flexi Hoses (strongly recommended)
Strom recommends flexi hoses on the 3/4" flow and return connections. Overtightening rigid compression fittings can damage boiler internals — this is explicitly excluded from warranty cover.
Key Features
14.4 kW — Maximum Single-Phase Heat-Only Output
This is the highest output available from a 230 V single-phase heat-only electric boiler. A typical UK three-bedroom semi-detached has a design heat load of 6 – 9 kW; larger or poorly insulated properties can reach 12 – 14 kW. At 14.4 kW this boiler covers the full single-phase residential range. Properties needing more than 14.4 kW would require a three-phase supply.
14.4 kW230V single phase62A / min 63A breaker
Smallest Possible Unit — 520 × 235 × 120 mm
Stripping out the pump and vessel leaves a unit roughly the size of a large hardback book. The 120 mm depth is less than many kitchen cupboard shelves. The SBSP15H fits inside a kitchen cabinet, on an airing cupboard wall, in a utility room corner, in a garage, or in any plant room with minimal clear wall space. It must be mounted upright on a vertical wall — any other orientation invalidates the warranty.
520 × 235 × 120mmUpright wall mount only
No Flue, No Gas, No Emissions at Point of Use
With no burner, no combustion and no exhaust gas, no flue is required and there is zero risk of carbon monoxide. This eliminates the structural and regulatory complexity of gas or oil installation and makes the boiler suitable for any indoor location without ventilation requirements. Ideal for off-gas-grid properties, flats where fluing is impractical, and heritage or listed buildings where external penetrations are restricted.
No flueZero CO riskOff-gas-grid compatible
LED Digital Display — External Thermostat Compatible
The LED digital display shows flow temperature and system status. Temperature is adjustable across the full 20 – 80°C range. An external room thermostat or time clock can be wired in for zone control and scheduling — compatible with standard S-plan, Y-plan and wiring centre configurations.
LED display20–80°CExternal thermostat compatible
Solar PV Diversion and Underfloor Heating Compatible
Works with solar PV diversion devices (myenergi Eddi, iBoost, etc.) to use surplus solar generation for space heating instead of exporting at low SEG rates. The 20 – 80°C flow temperature range also makes it compatible with wet underfloor heating systems, which typically operate at 35 – 55°C (use manifold mixing valves to maintain correct UFH temperatures).
Solar PV diversionUnderfloor heating20–80°C range
Near-Silent Operation — Minimal Moving Parts
No burner, no fan, no heat exchanger, no internal pump. The heating element operates in complete silence. The only sound in the system comes from the external pump, which the installer can position to minimise noise transmission. Minimal moving parts means fewer wear components, lower servicing requirements and high long-term reliability.
No burner or fanNear-silentLow servicing requirement
Built-in Auto Air Vent and PRV Connection
An automatic air vent is built into the boiler. If used with an indirect cylinder, an additional auto air vent should be fitted near the cylinder coil. The 15 mm compression PRV connection accepts the pressure relief valve, which must be piped to a safe discharge point. A system drain point should be fitted at the lowest point of the circuit to allow draining without discharging through the PRV.
Built-in auto air vent15mm compression PRV connection
All Standard Heating Configurations Supported
Compatible with S-plan, Y-plan, fully pumped and gravity-assisted systems. Supplies a heating circuit and can feed an indirect hot water cylinder via a motorised valve or cylinder thermostat. System design to BS EN 12828 / 12831. Water treatment to BS EN 7593 with a proprietary inhibitor to protect the heating element and pipework.
S-plan and Y-planSealed systemIndirect cylinder
Installation Quick Reference
Electrical supply
230 V single phase. 62 A draw. Min 63 A circuit breaker. Min 10 mm² cable. Linked isolator with min 3 mm contact gap in every pole. Cable entry at top right panel.
Electrical certification
Connection by a competent electrician to BS 7671 (18th Edition). System must be earthed before any current is applied.
Plumbing certification
By a qualified and certified heating engineer. Design to BS EN 12828, 12831 and 14336. Water treatment to BS EN 7593.
System pressure
Fill to 1.0 – 1.5 bar. Fill slowly, vent all manual release valves to purge air. Remove filling loop after commissioning.
Pipework connections
3/4" male (22 mm pipe). Full bore isolation valves on flow and return. Flexi hoses strongly recommended. Do not overtighten rigid fittings.
Mounting and location
Upright on vertical wall only — other orientations void warranty. Wall must support boiler weight when filled. Allow access for front panel removal. Avoid frost-risk locations.
Technical Specifications
| Boiler Performance | |
| Model | SBSP15H |
| Heat output | 14.4 kW |
| ERP rating (heating) | D |
| Flow temperature range | 20 – 80°C (adjustable) |
| Heating pressure range | 0.5 – 1.5 bar |
| Electrical | |
| Power supply | 230 V, single phase |
| Current draw | 62 A |
| Minimum circuit breaker | 63 A |
| Minimum cable size | 10 mm² |
| Connections | |
| Flow and return | 3/4" Male (22 mm pipe) |
| PRV connection | 15 mm compression |
| Physical | |
| Dimensions (H × W × D) | 520 × 235 × 120 mm |
| Mounting | Wall-mounted, upright only (warranty void otherwise) |
| Features | |
| Display | LED digital display |
| Built-in auto air vent | Yes |
| Integrated pump | No — external pump required |
| Integrated expansion vessel | No — external expansion vessel required |
| Flue required | No |
| Emissions at point of use | Zero (no combustion) |
| Compatibility | |
| Heating systems | S-plan, Y-plan, sealed system, fully pumped |
| Domestic hot water | Via indirect cylinder (sold separately) |
| Solar PV diversion | Compatible |
| Underfloor heating | Compatible |
| Standards | |
| Heating design | BS EN 12828, BS EN 12831, BS EN 14336 |
| Electrical | BS 7671 (18th Edition IEE Wiring Regulations) |
| Water treatment | BS EN 7593 |
| Warranty | |
| Standard warranty | 1 year (without registration) |
| Extended warranty | 2 years (register within 45 days at stromltd.com/guarantee) |
| Warranty holder | Legal owner of building only |
| Box Contents | |
| Included | Boiler unit, wall fixings, mounting guide, installation manual, registration card |
| EAN barcode | 5060438333571 |
Frequently Asked Questions
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