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Sunamp Thermino xPlus Heat Battery – Indirect, Boiler & Heat Pump, 150–300L, Energy A+, 10-Year Warranty
Sunamp Thermino xPlus Heat Battery – Indirect, Boiler & Heat Pump, 150–300L, Energy A+, 10-Year Warranty
The Sunamp Thermino xPlus is an indirect heat battery — a compact, mains-pressure hot water system for system boilers, combi pre-heat, air source heat pumps and ground source heat pumps. Using Plentigrade P58 phase change material (PCM), it achieves Energy Class A+ when charged by a heat pump — storing thermal energy far more densely than water and measuring up to 4× smaller than the indirect cylinder it replaces. Available in three sizes: 150, 210 and 300 (litre equivalents). The Optimino key system allows the heat source to be changed — from boiler to heat pump, or from heat pump to heat pump + solar PV — by swapping the key, never the unit. Mains-pressure hot water on demand. No mandatory annual servicing. 10-year warranty on heating element and PCM core.
Energy A+
Class (Heat Pump)
Up to 4×
Smaller
199–402 L
V40 Output
10 yr
Warranty
4 Optimino
Keys
No Annual
Service
Thermino xPlus Model Range — Technical Data
| Model | Equiv. Cylinder (L) | V40 Primary (L) | Max HW Flow (L/min) | Max Charge Flow (L/min) | Heat Loss (kWh/24h) | Energy Class | Weight Filled (kg) | Height (mm) |
| 150 xPlus | 142 | 199 | 15 | 15 | 0.67 (28.1W) | A+ | 136 | 640 |
| 210 xPlus | 212 | 301 | 20 | 20 | 0.77 (32.1W) | A+ | 187 | 870 |
| 300 xPlus | 284 | 402 | 25 | 25 | 0.84 (34.9W) | A+ | 233 | 1050 |
All models: Width 365mm × Depth 575mm. Minimum supply pressure: 1.5 bar. Maximum working pressure: 5 bar. Recommended TMV: 45–55°C. Max heat source flow temperature: 80°C. V40 = litres of hot water available at 40°C.
⚠ Scald Prevention: In line with UK Building Regulations, a thermostatic mixing valve (TMV) must be fitted at the heat battery outlet, set to deliver hot water at 45–55°C. The PCM stores energy at temperatures that can cause severe burns if delivered unmixed.
Key Features
Indirect Heat Battery — For Boilers and Heat Pumps
The Thermino xPlus is an indirect heat battery that replaces a traditional indirect hot water cylinder. It is charged by an external heat source via an internal heat exchanger — system boiler, combi boiler (pre-heat), air source heat pump (ASHP) or ground source heat pump (GSHP). Grid electricity serves as a backup or boost charge via the built-in immersion element.
System boilerCombi pre-heatASHP / GSHP
Plentigrade PCM — Up to 4× Smaller, Energy Class A+
Uses Plentigrade P58 PCM — Sunamp's patented phase change material. The xPlus achieves Energy Class A+ — higher than the ePlus (Class C) — because the heat pump charging pathway is significantly more efficient than direct electric heating. Up to 4× smaller than the indirect cylinder it replaces.
Plentigrade P58 PCMEnergy Class A+Up to 4× smaller
Optimino Keys — Switch Heat Source Without Changing the Unit
The Optimino key system allows the xPlus to adapt to a new heat source at any time. Start with a system boiler (vf key); later switch to a heat pump (hp key) or heat pump + solar PV (hpPV key) — simply swap the Optimino key. No new heat battery is needed. The xPlus supports a staged transition from gas to fully renewable hot water.
vf key (boiler)hp key (heat pump)hpPV key (HP + PV)
Reduces Gas Consumption and Carbon Emissions
When charged by a system boiler the xPlus reduces gas consumption by storing heat more efficiently than a conventional cylinder. Paired with a combi boiler, the battery pre-heats water reducing the demand placed on the boiler. Switching to a heat pump via the hp key can deliver a 72% reduction in carbon emissions for hot water compared with gas.
Reduces gas use72% carbon reduction (HP)
Mains-Pressure Hot Water On Demand — Three Sizes
Three models: 150, 210 and 300 (litre equivalents). V40 output from 199 litres (150 model) to 402 litres (300 model) at 40°C. Maximum hot water flow rates from 15 l/min to 25 l/min for simultaneous outlets.
199–402 L at 40°C15–25 l/min max flowMains pressure
Ultra-Low Heat Loss — Energy Class A+
Heat loss of 0.67–0.84 kWh/24h across the range — compared with a typical indirect cylinder losing 1.5–3+ kWh/24h. The A+ energy label reflects the combined efficiency of PCM storage and heat pump charging. No mandatory annual servicing required.
A+ energy classUltra-low heat lossNo annual service
Flexible Pipe Access — Three Sides, Modular and Scalable
Pipe and cable entries on three sides. Multiple units can be connected in series or parallel for higher-demand applications. All models share the same 365 × 575mm footprint — only height varies.
3-side accessModular scalable
10-Year Warranty on Heating Element and PCM Core
Market-leading 10-year warranty on the heating element and Plentigrade P58 storage core for products purchased and installed in the UK.
10-year warranty
Technical Specifications
| Heat Source Compatibility | |
| Primary Heat Source | System boiler, combi boiler (pre-heat), ASHP or GSHP via heat exchanger |
| Backup Electric Charging | Yes — built-in immersion element (grid electricity) |
| Max Heat Source Flow Temperature | 80°C |
| Max Charging Flow Rate | 15 l/min (150) / 20 l/min (210) / 25 l/min (300) |
| Hydraulic — All Models | |
| Minimum Supply Pressure | 1.5 bar (0.15 MPa) |
| Recommended Operating Pressure / PRV | 3 bar (0.3 MPa) |
| Maximum Working Pressure | 5 bar (0.5 MPa) |
| BERV Recommended Set Point | 6 bar (0.6 MPa) |
| Maximum Design Pressure | 10 bar (1.0 MPa) |
| Recommended TMV Setting | 45–55°C |
| Physical — All Models | |
| Width | 365mm |
| Depth | 575mm |
| Pipe / Cable Access | Three sides (rear, left, right) |
| Optimino Keys Available | |
| vf key | System boiler / volt-free control |
| vfPV key | System boiler + solar PV |
| hp key | Heat pump (ASHP/GSHP) |
| hpPV key | Heat pump + solar PV |
| PCM & Warranty | |
| Phase Change Material | Plentigrade P58 (patented, non-toxic, non-flammable) |
| Warranty (Heating Element + PCM Core) | 10 years (UK purchase and installation, online registration) |
| Country of Origin | United Kingdom (Macmerry, East Lothian) |
ℹ Installation: Must be installed by a qualified and competent person. Always refer to the manufacturer's latest installation manual. In line with UK Building Regulations, a thermostatic mixing valve (TMV) must be fitted at the outlet of all Thermino heat batteries to prevent scalding.
Frequently Asked Questions
Related Products
Sunamp Thermino ePlus Heat Battery
Direct electric — grid, off-peak and solar PV
Sunamp A2057 Installation Kit
PRV, TMV, expansion vessel — required accessories
Solar iBoost+ Immersion Controller
PV diversion compatible with vfPV / hpPV key configurations
Select Type
From $1,073.73
Original: $3,067.80
-65%Sunamp Thermino xPlus Heat Battery – Indirect, Boiler & Heat Pump, 150–300L, Energy A+, 10-Year Warranty—
$3,067.80
$1,073.73More Images
Sunamp Thermino xPlus Heat Battery – Indirect, Boiler & Heat Pump, 150–300L, Energy A+, 10-Year Warranty
The Sunamp Thermino xPlus is an indirect heat battery — a compact, mains-pressure hot water system for system boilers, combi pre-heat, air source heat pumps and ground source heat pumps. Using Plentigrade P58 phase change material (PCM), it achieves Energy Class A+ when charged by a heat pump — storing thermal energy far more densely than water and measuring up to 4× smaller than the indirect cylinder it replaces. Available in three sizes: 150, 210 and 300 (litre equivalents). The Optimino key system allows the heat source to be changed — from boiler to heat pump, or from heat pump to heat pump + solar PV — by swapping the key, never the unit. Mains-pressure hot water on demand. No mandatory annual servicing. 10-year warranty on heating element and PCM core.
Energy A+
Class (Heat Pump)
Up to 4×
Smaller
199–402 L
V40 Output
10 yr
Warranty
4 Optimino
Keys
No Annual
Service
Thermino xPlus Model Range — Technical Data
| Model | Equiv. Cylinder (L) | V40 Primary (L) | Max HW Flow (L/min) | Max Charge Flow (L/min) | Heat Loss (kWh/24h) | Energy Class | Weight Filled (kg) | Height (mm) |
| 150 xPlus | 142 | 199 | 15 | 15 | 0.67 (28.1W) | A+ | 136 | 640 |
| 210 xPlus | 212 | 301 | 20 | 20 | 0.77 (32.1W) | A+ | 187 | 870 |
| 300 xPlus | 284 | 402 | 25 | 25 | 0.84 (34.9W) | A+ | 233 | 1050 |
All models: Width 365mm × Depth 575mm. Minimum supply pressure: 1.5 bar. Maximum working pressure: 5 bar. Recommended TMV: 45–55°C. Max heat source flow temperature: 80°C. V40 = litres of hot water available at 40°C.
⚠ Scald Prevention: In line with UK Building Regulations, a thermostatic mixing valve (TMV) must be fitted at the heat battery outlet, set to deliver hot water at 45–55°C. The PCM stores energy at temperatures that can cause severe burns if delivered unmixed.
Key Features
Indirect Heat Battery — For Boilers and Heat Pumps
The Thermino xPlus is an indirect heat battery that replaces a traditional indirect hot water cylinder. It is charged by an external heat source via an internal heat exchanger — system boiler, combi boiler (pre-heat), air source heat pump (ASHP) or ground source heat pump (GSHP). Grid electricity serves as a backup or boost charge via the built-in immersion element.
System boilerCombi pre-heatASHP / GSHP
Plentigrade PCM — Up to 4× Smaller, Energy Class A+
Uses Plentigrade P58 PCM — Sunamp's patented phase change material. The xPlus achieves Energy Class A+ — higher than the ePlus (Class C) — because the heat pump charging pathway is significantly more efficient than direct electric heating. Up to 4× smaller than the indirect cylinder it replaces.
Plentigrade P58 PCMEnergy Class A+Up to 4× smaller
Optimino Keys — Switch Heat Source Without Changing the Unit
The Optimino key system allows the xPlus to adapt to a new heat source at any time. Start with a system boiler (vf key); later switch to a heat pump (hp key) or heat pump + solar PV (hpPV key) — simply swap the Optimino key. No new heat battery is needed. The xPlus supports a staged transition from gas to fully renewable hot water.
vf key (boiler)hp key (heat pump)hpPV key (HP + PV)
Reduces Gas Consumption and Carbon Emissions
When charged by a system boiler the xPlus reduces gas consumption by storing heat more efficiently than a conventional cylinder. Paired with a combi boiler, the battery pre-heats water reducing the demand placed on the boiler. Switching to a heat pump via the hp key can deliver a 72% reduction in carbon emissions for hot water compared with gas.
Reduces gas use72% carbon reduction (HP)
Mains-Pressure Hot Water On Demand — Three Sizes
Three models: 150, 210 and 300 (litre equivalents). V40 output from 199 litres (150 model) to 402 litres (300 model) at 40°C. Maximum hot water flow rates from 15 l/min to 25 l/min for simultaneous outlets.
199–402 L at 40°C15–25 l/min max flowMains pressure
Ultra-Low Heat Loss — Energy Class A+
Heat loss of 0.67–0.84 kWh/24h across the range — compared with a typical indirect cylinder losing 1.5–3+ kWh/24h. The A+ energy label reflects the combined efficiency of PCM storage and heat pump charging. No mandatory annual servicing required.
A+ energy classUltra-low heat lossNo annual service
Flexible Pipe Access — Three Sides, Modular and Scalable
Pipe and cable entries on three sides. Multiple units can be connected in series or parallel for higher-demand applications. All models share the same 365 × 575mm footprint — only height varies.
3-side accessModular scalable
10-Year Warranty on Heating Element and PCM Core
Market-leading 10-year warranty on the heating element and Plentigrade P58 storage core for products purchased and installed in the UK.
10-year warranty
Technical Specifications
| Heat Source Compatibility | |
| Primary Heat Source | System boiler, combi boiler (pre-heat), ASHP or GSHP via heat exchanger |
| Backup Electric Charging | Yes — built-in immersion element (grid electricity) |
| Max Heat Source Flow Temperature | 80°C |
| Max Charging Flow Rate | 15 l/min (150) / 20 l/min (210) / 25 l/min (300) |
| Hydraulic — All Models | |
| Minimum Supply Pressure | 1.5 bar (0.15 MPa) |
| Recommended Operating Pressure / PRV | 3 bar (0.3 MPa) |
| Maximum Working Pressure | 5 bar (0.5 MPa) |
| BERV Recommended Set Point | 6 bar (0.6 MPa) |
| Maximum Design Pressure | 10 bar (1.0 MPa) |
| Recommended TMV Setting | 45–55°C |
| Physical — All Models | |
| Width | 365mm |
| Depth | 575mm |
| Pipe / Cable Access | Three sides (rear, left, right) |
| Optimino Keys Available | |
| vf key | System boiler / volt-free control |
| vfPV key | System boiler + solar PV |
| hp key | Heat pump (ASHP/GSHP) |
| hpPV key | Heat pump + solar PV |
| PCM & Warranty | |
| Phase Change Material | Plentigrade P58 (patented, non-toxic, non-flammable) |
| Warranty (Heating Element + PCM Core) | 10 years (UK purchase and installation, online registration) |
| Country of Origin | United Kingdom (Macmerry, East Lothian) |
ℹ Installation: Must be installed by a qualified and competent person. Always refer to the manufacturer's latest installation manual. In line with UK Building Regulations, a thermostatic mixing valve (TMV) must be fitted at the outlet of all Thermino heat batteries to prevent scalding.
Frequently Asked Questions
Related Products
Sunamp Thermino ePlus Heat Battery
Direct electric — grid, off-peak and solar PV
Sunamp A2057 Installation Kit
PRV, TMV, expansion vessel — required accessories
Solar iBoost+ Immersion Controller
PV diversion compatible with vfPV / hpPV key configurations
Product Information
Product Information
Shipping & Returns
Shipping & Returns
Description
The Sunamp Thermino xPlus is an indirect heat battery — a compact, mains-pressure hot water system for system boilers, combi pre-heat, air source heat pumps and ground source heat pumps. Using Plentigrade P58 phase change material (PCM), it achieves Energy Class A+ when charged by a heat pump — storing thermal energy far more densely than water and measuring up to 4× smaller than the indirect cylinder it replaces. Available in three sizes: 150, 210 and 300 (litre equivalents). The Optimino key system allows the heat source to be changed — from boiler to heat pump, or from heat pump to heat pump + solar PV — by swapping the key, never the unit. Mains-pressure hot water on demand. No mandatory annual servicing. 10-year warranty on heating element and PCM core.
Energy A+
Class (Heat Pump)
Up to 4×
Smaller
199–402 L
V40 Output
10 yr
Warranty
4 Optimino
Keys
No Annual
Service
Thermino xPlus Model Range — Technical Data
| Model | Equiv. Cylinder (L) | V40 Primary (L) | Max HW Flow (L/min) | Max Charge Flow (L/min) | Heat Loss (kWh/24h) | Energy Class | Weight Filled (kg) | Height (mm) |
| 150 xPlus | 142 | 199 | 15 | 15 | 0.67 (28.1W) | A+ | 136 | 640 |
| 210 xPlus | 212 | 301 | 20 | 20 | 0.77 (32.1W) | A+ | 187 | 870 |
| 300 xPlus | 284 | 402 | 25 | 25 | 0.84 (34.9W) | A+ | 233 | 1050 |
All models: Width 365mm × Depth 575mm. Minimum supply pressure: 1.5 bar. Maximum working pressure: 5 bar. Recommended TMV: 45–55°C. Max heat source flow temperature: 80°C. V40 = litres of hot water available at 40°C.
⚠ Scald Prevention: In line with UK Building Regulations, a thermostatic mixing valve (TMV) must be fitted at the heat battery outlet, set to deliver hot water at 45–55°C. The PCM stores energy at temperatures that can cause severe burns if delivered unmixed.
Key Features
Indirect Heat Battery — For Boilers and Heat Pumps
The Thermino xPlus is an indirect heat battery that replaces a traditional indirect hot water cylinder. It is charged by an external heat source via an internal heat exchanger — system boiler, combi boiler (pre-heat), air source heat pump (ASHP) or ground source heat pump (GSHP). Grid electricity serves as a backup or boost charge via the built-in immersion element.
System boilerCombi pre-heatASHP / GSHP
Plentigrade PCM — Up to 4× Smaller, Energy Class A+
Uses Plentigrade P58 PCM — Sunamp's patented phase change material. The xPlus achieves Energy Class A+ — higher than the ePlus (Class C) — because the heat pump charging pathway is significantly more efficient than direct electric heating. Up to 4× smaller than the indirect cylinder it replaces.
Plentigrade P58 PCMEnergy Class A+Up to 4× smaller
Optimino Keys — Switch Heat Source Without Changing the Unit
The Optimino key system allows the xPlus to adapt to a new heat source at any time. Start with a system boiler (vf key); later switch to a heat pump (hp key) or heat pump + solar PV (hpPV key) — simply swap the Optimino key. No new heat battery is needed. The xPlus supports a staged transition from gas to fully renewable hot water.
vf key (boiler)hp key (heat pump)hpPV key (HP + PV)
Reduces Gas Consumption and Carbon Emissions
When charged by a system boiler the xPlus reduces gas consumption by storing heat more efficiently than a conventional cylinder. Paired with a combi boiler, the battery pre-heats water reducing the demand placed on the boiler. Switching to a heat pump via the hp key can deliver a 72% reduction in carbon emissions for hot water compared with gas.
Reduces gas use72% carbon reduction (HP)
Mains-Pressure Hot Water On Demand — Three Sizes
Three models: 150, 210 and 300 (litre equivalents). V40 output from 199 litres (150 model) to 402 litres (300 model) at 40°C. Maximum hot water flow rates from 15 l/min to 25 l/min for simultaneous outlets.
199–402 L at 40°C15–25 l/min max flowMains pressure
Ultra-Low Heat Loss — Energy Class A+
Heat loss of 0.67–0.84 kWh/24h across the range — compared with a typical indirect cylinder losing 1.5–3+ kWh/24h. The A+ energy label reflects the combined efficiency of PCM storage and heat pump charging. No mandatory annual servicing required.
A+ energy classUltra-low heat lossNo annual service
Flexible Pipe Access — Three Sides, Modular and Scalable
Pipe and cable entries on three sides. Multiple units can be connected in series or parallel for higher-demand applications. All models share the same 365 × 575mm footprint — only height varies.
3-side accessModular scalable
10-Year Warranty on Heating Element and PCM Core
Market-leading 10-year warranty on the heating element and Plentigrade P58 storage core for products purchased and installed in the UK.
10-year warranty
Technical Specifications
| Heat Source Compatibility | |
| Primary Heat Source | System boiler, combi boiler (pre-heat), ASHP or GSHP via heat exchanger |
| Backup Electric Charging | Yes — built-in immersion element (grid electricity) |
| Max Heat Source Flow Temperature | 80°C |
| Max Charging Flow Rate | 15 l/min (150) / 20 l/min (210) / 25 l/min (300) |
| Hydraulic — All Models | |
| Minimum Supply Pressure | 1.5 bar (0.15 MPa) |
| Recommended Operating Pressure / PRV | 3 bar (0.3 MPa) |
| Maximum Working Pressure | 5 bar (0.5 MPa) |
| BERV Recommended Set Point | 6 bar (0.6 MPa) |
| Maximum Design Pressure | 10 bar (1.0 MPa) |
| Recommended TMV Setting | 45–55°C |
| Physical — All Models | |
| Width | 365mm |
| Depth | 575mm |
| Pipe / Cable Access | Three sides (rear, left, right) |
| Optimino Keys Available | |
| vf key | System boiler / volt-free control |
| vfPV key | System boiler + solar PV |
| hp key | Heat pump (ASHP/GSHP) |
| hpPV key | Heat pump + solar PV |
| PCM & Warranty | |
| Phase Change Material | Plentigrade P58 (patented, non-toxic, non-flammable) |
| Warranty (Heating Element + PCM Core) | 10 years (UK purchase and installation, online registration) |
| Country of Origin | United Kingdom (Macmerry, East Lothian) |
ℹ Installation: Must be installed by a qualified and competent person. Always refer to the manufacturer's latest installation manual. In line with UK Building Regulations, a thermostatic mixing valve (TMV) must be fitted at the outlet of all Thermino heat batteries to prevent scalding.
Frequently Asked Questions
Related Products
Sunamp Thermino ePlus Heat Battery
Direct electric — grid, off-peak and solar PV
Sunamp A2057 Installation Kit
PRV, TMV, expansion vessel — required accessories
Solar iBoost+ Immersion Controller
PV diversion compatible with vfPV / hpPV key configurations
