Vaillant aroTHERM 45 Litre Wall-Hung Buffer Vessel for Air Source Heat Pumps
The Vaillant aroTHERM 45 Litre Buffer Vessel (article number 0010038365) is a wall-hung 45-litre buffer tank engineered specifically for the Vaillant aroTHERM plus air-source heat pump range. It provides the additional system water volume the heat pump needs to protect against short-cycling, ensure clean defrost cycles and maintain stable flow temperatures — improving seasonal efficiency and component life.
Supplied as a complete pack with the buffer, four 28 mm conversion fittings for direct connection to standard UK heating pipework, and a VR 10 NTC temperature sensor that fits the buffer's integral sensor pocket. The vessel features six G 1¼" connections for hybrid, cascade and decoupled-buffer layouts, factory-fitted insulation achieving an ErP class B standing-loss rating, and a tidy outer case for a clean installed finish.
Engineered specifically for the Vaillant aroTHERM plus range (3.5 / 5 / 7 / 10 / 12 kW). Fitting and connection sizes match the published aroTHERM plus hydraulic schematics out of the box.
Six G 1¼" tappings allow flexible system design — hybrid layouts linking heat pump and a second heat source, four-pipe decoupled buffers, return volumisers, or cascade headers across multiple aroTHERM plus units.
Supplied with a genuine Vaillant VR 10 NTC temperature sensor that fits the integral sensor pocket — feeding accurate buffer-tank temperature back to the aroTHERM controller for tighter heat-pump output modulation.
The pack includes four conversion fittings stepping the G 1¼" tappings down to 28 mm compression — the standard primary pipework size on aroTHERM plus installations.
Wall-mounted format keeps the plant-room footprint small, and factory-fitted insulation in a smart outer case keeps standing losses to ErP class B levels with no field-applied lagging required.
Use the buffer to link two heat sources (heat pump plus boiler or solar thermal) into one heating circuit — the foundation for a properly hydraulically-separated hybrid system.
| Manufacturer | Vaillant |
| Product | aroTHERM 45 litre buffer vessel |
| Article number (MPN) | 0010038365 |
| Buffer capacity | 45 litres |
| Format | Wall-hung |
| Number of connections | 6 × G 1¼" + 1 × G ½" sensor pocket |
| Connection size | G 1¼" (with 4 × 28 mm conversion fittings supplied) |
| Heat pump compatibility | Vaillant aroTHERM plus 3.5 / 5 / 7 / 10 / 12 kW |
| System layouts supported | Decoupled 4-pipe buffer, return volumiser, hybrid buffer, cascade header |
| Insulation | Factory-fitted, high-performance |
| ErP standing-loss class | B |
| Sensor included | VR 10 NTC temperature sensor |
| Package contents | Buffer + 4 × 28 mm conversion fittings + VR 10 sensor |
| Approximate dimensions (H × W × D) | Approx. 939 × 467 × 365 mm |
| Weight (net) | Approx. 20 kg |
Why does an aroTHERM plus need a buffer vessel?
Heat pumps work most efficiently when they run for long, steady cycles. If the system water volume is too small, the heat pump can short-cycle — switching on and off rapidly, wearing components and reducing efficiency. A buffer adds the necessary volume so the compressor can run a sensible minimum cycle, ensures there's enough water on the system side for a clean defrost cycle, and hydraulically separates the heat pump from TRV-controlled or zoned circuits where flow can change abruptly.
Can I use it with a non-Vaillant heat pump?
Vaillant supplies and warranties this product specifically as part of the aroTHERM plus system. Use with another manufacturer's heat pump is not supported, and the included VR 10 sensor is intended for the Vaillant controller's input rather than third-party controls.
Which system layout should I use?
The aroTHERM plus Installer's Quick Guide shows four buffer configurations: (A) decoupled 4-pipe heat-pump buffer, (B) buffer as return volumiser, (C) hybrid with decoupled buffer, and (D) hybrid using heat pump for system circulation. Choose based on whether the system is heat-pump only or hybrid, and whether the heat pump or a separate system pump handles emitter-side circulation.
Are the fittings supplied with the buffer?
Yes — the pack includes the buffer, four 28 mm conversion fittings for the G 1¼" tappings, and a VR 10 temperature sensor. Additional sensors, ball-filter valves and low-loss headers are available separately as Vaillant aroTHERM accessories.
Original: $1,125.62
-65%$1,125.62
$393.97Vaillant aroTHERM 45 Litre Wall-Hung Buffer Vessel for Air Source Heat Pumps
The Vaillant aroTHERM 45 Litre Buffer Vessel (article number 0010038365) is a wall-hung 45-litre buffer tank engineered specifically for the Vaillant aroTHERM plus air-source heat pump range. It provides the additional system water volume the heat pump needs to protect against short-cycling, ensure clean defrost cycles and maintain stable flow temperatures — improving seasonal efficiency and component life.
Supplied as a complete pack with the buffer, four 28 mm conversion fittings for direct connection to standard UK heating pipework, and a VR 10 NTC temperature sensor that fits the buffer's integral sensor pocket. The vessel features six G 1¼" connections for hybrid, cascade and decoupled-buffer layouts, factory-fitted insulation achieving an ErP class B standing-loss rating, and a tidy outer case for a clean installed finish.
Engineered specifically for the Vaillant aroTHERM plus range (3.5 / 5 / 7 / 10 / 12 kW). Fitting and connection sizes match the published aroTHERM plus hydraulic schematics out of the box.
Six G 1¼" tappings allow flexible system design — hybrid layouts linking heat pump and a second heat source, four-pipe decoupled buffers, return volumisers, or cascade headers across multiple aroTHERM plus units.
Supplied with a genuine Vaillant VR 10 NTC temperature sensor that fits the integral sensor pocket — feeding accurate buffer-tank temperature back to the aroTHERM controller for tighter heat-pump output modulation.
The pack includes four conversion fittings stepping the G 1¼" tappings down to 28 mm compression — the standard primary pipework size on aroTHERM plus installations.
Wall-mounted format keeps the plant-room footprint small, and factory-fitted insulation in a smart outer case keeps standing losses to ErP class B levels with no field-applied lagging required.
Use the buffer to link two heat sources (heat pump plus boiler or solar thermal) into one heating circuit — the foundation for a properly hydraulically-separated hybrid system.
| Manufacturer | Vaillant |
| Product | aroTHERM 45 litre buffer vessel |
| Article number (MPN) | 0010038365 |
| Buffer capacity | 45 litres |
| Format | Wall-hung |
| Number of connections | 6 × G 1¼" + 1 × G ½" sensor pocket |
| Connection size | G 1¼" (with 4 × 28 mm conversion fittings supplied) |
| Heat pump compatibility | Vaillant aroTHERM plus 3.5 / 5 / 7 / 10 / 12 kW |
| System layouts supported | Decoupled 4-pipe buffer, return volumiser, hybrid buffer, cascade header |
| Insulation | Factory-fitted, high-performance |
| ErP standing-loss class | B |
| Sensor included | VR 10 NTC temperature sensor |
| Package contents | Buffer + 4 × 28 mm conversion fittings + VR 10 sensor |
| Approximate dimensions (H × W × D) | Approx. 939 × 467 × 365 mm |
| Weight (net) | Approx. 20 kg |
Why does an aroTHERM plus need a buffer vessel?
Heat pumps work most efficiently when they run for long, steady cycles. If the system water volume is too small, the heat pump can short-cycle — switching on and off rapidly, wearing components and reducing efficiency. A buffer adds the necessary volume so the compressor can run a sensible minimum cycle, ensures there's enough water on the system side for a clean defrost cycle, and hydraulically separates the heat pump from TRV-controlled or zoned circuits where flow can change abruptly.
Can I use it with a non-Vaillant heat pump?
Vaillant supplies and warranties this product specifically as part of the aroTHERM plus system. Use with another manufacturer's heat pump is not supported, and the included VR 10 sensor is intended for the Vaillant controller's input rather than third-party controls.
Which system layout should I use?
The aroTHERM plus Installer's Quick Guide shows four buffer configurations: (A) decoupled 4-pipe heat-pump buffer, (B) buffer as return volumiser, (C) hybrid with decoupled buffer, and (D) hybrid using heat pump for system circulation. Choose based on whether the system is heat-pump only or hybrid, and whether the heat pump or a separate system pump handles emitter-side circulation.
Are the fittings supplied with the buffer?
Yes — the pack includes the buffer, four 28 mm conversion fittings for the G 1¼" tappings, and a VR 10 temperature sensor. Additional sensors, ball-filter valves and low-loss headers are available separately as Vaillant aroTHERM accessories.
Product Information
Product Information
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Description
The Vaillant aroTHERM 45 Litre Buffer Vessel (article number 0010038365) is a wall-hung 45-litre buffer tank engineered specifically for the Vaillant aroTHERM plus air-source heat pump range. It provides the additional system water volume the heat pump needs to protect against short-cycling, ensure clean defrost cycles and maintain stable flow temperatures — improving seasonal efficiency and component life.
Supplied as a complete pack with the buffer, four 28 mm conversion fittings for direct connection to standard UK heating pipework, and a VR 10 NTC temperature sensor that fits the buffer's integral sensor pocket. The vessel features six G 1¼" connections for hybrid, cascade and decoupled-buffer layouts, factory-fitted insulation achieving an ErP class B standing-loss rating, and a tidy outer case for a clean installed finish.
Engineered specifically for the Vaillant aroTHERM plus range (3.5 / 5 / 7 / 10 / 12 kW). Fitting and connection sizes match the published aroTHERM plus hydraulic schematics out of the box.
Six G 1¼" tappings allow flexible system design — hybrid layouts linking heat pump and a second heat source, four-pipe decoupled buffers, return volumisers, or cascade headers across multiple aroTHERM plus units.
Supplied with a genuine Vaillant VR 10 NTC temperature sensor that fits the integral sensor pocket — feeding accurate buffer-tank temperature back to the aroTHERM controller for tighter heat-pump output modulation.
The pack includes four conversion fittings stepping the G 1¼" tappings down to 28 mm compression — the standard primary pipework size on aroTHERM plus installations.
Wall-mounted format keeps the plant-room footprint small, and factory-fitted insulation in a smart outer case keeps standing losses to ErP class B levels with no field-applied lagging required.
Use the buffer to link two heat sources (heat pump plus boiler or solar thermal) into one heating circuit — the foundation for a properly hydraulically-separated hybrid system.
| Manufacturer | Vaillant |
| Product | aroTHERM 45 litre buffer vessel |
| Article number (MPN) | 0010038365 |
| Buffer capacity | 45 litres |
| Format | Wall-hung |
| Number of connections | 6 × G 1¼" + 1 × G ½" sensor pocket |
| Connection size | G 1¼" (with 4 × 28 mm conversion fittings supplied) |
| Heat pump compatibility | Vaillant aroTHERM plus 3.5 / 5 / 7 / 10 / 12 kW |
| System layouts supported | Decoupled 4-pipe buffer, return volumiser, hybrid buffer, cascade header |
| Insulation | Factory-fitted, high-performance |
| ErP standing-loss class | B |
| Sensor included | VR 10 NTC temperature sensor |
| Package contents | Buffer + 4 × 28 mm conversion fittings + VR 10 sensor |
| Approximate dimensions (H × W × D) | Approx. 939 × 467 × 365 mm |
| Weight (net) | Approx. 20 kg |
Why does an aroTHERM plus need a buffer vessel?
Heat pumps work most efficiently when they run for long, steady cycles. If the system water volume is too small, the heat pump can short-cycle — switching on and off rapidly, wearing components and reducing efficiency. A buffer adds the necessary volume so the compressor can run a sensible minimum cycle, ensures there's enough water on the system side for a clean defrost cycle, and hydraulically separates the heat pump from TRV-controlled or zoned circuits where flow can change abruptly.
Can I use it with a non-Vaillant heat pump?
Vaillant supplies and warranties this product specifically as part of the aroTHERM plus system. Use with another manufacturer's heat pump is not supported, and the included VR 10 sensor is intended for the Vaillant controller's input rather than third-party controls.
Which system layout should I use?
The aroTHERM plus Installer's Quick Guide shows four buffer configurations: (A) decoupled 4-pipe heat-pump buffer, (B) buffer as return volumiser, (C) hybrid with decoupled buffer, and (D) hybrid using heat pump for system circulation. Choose based on whether the system is heat-pump only or hybrid, and whether the heat pump or a separate system pump handles emitter-side circulation.
Are the fittings supplied with the buffer?
Yes — the pack includes the buffer, four 28 mm conversion fittings for the G 1¼" tappings, and a VR 10 temperature sensor. Additional sensors, ball-filter valves and low-loss headers are available separately as Vaillant aroTHERM accessories.
