OSO Acc350 SuperStream 350L Cold Water Accumulator Tank
OSO Acc350 SuperStream 350 L Accumulator — Extra-large power-free cold water accumulator tank booster with patented CAD2 diaphragm technology | Up to ~80 l/min extra flow | Silent, zero-energy, zero-maintenance | ~175 L usable volume | Vertical install only | WRAS-approved butyl membrane | 5-year warranty | Ideal for large homes, guest houses or light commercial
The OSO SuperStream Acc350 is the heavy-duty vertical accumulator built for properties with exceptional simultaneous demand — larger family homes, bed & breakfasts, small care facilities or light commercial setups where 3–5+ outlets may run at once. With 350 litres total volume and around 175 litres of usable stored water (at 1.5 bar differential), it offers the longest buffer of boosted performance before relying purely on incoming mains supply.
Powered solely by mains pressure via the patented CAD2 diaphragm system, it delivers silent, maintenance-free flow supplementation of up to ~80 litres per minute with zero electricity consumption, zero noise and zero ongoing costs. The robust composite fiberglass/epoxy shell is corrosion-resistant, weighs only 35 kg empty (much lighter than equivalent steel vessels), and is designed for long-term reliability in demanding environments.
This model is vertical-mount only (no horizontal cradle option), making it best suited to taller spaces such as plant rooms, garages or dedicated cupboards. Like all SuperStream units, it requires no annual servicing and continues to function perfectly during power outages — a true "fit and forget" solution.
What Makes the SuperStream Acc350 Special?
- Maximum Domestic/Commercial Reserve — ~175 L usable volume — sustains high flow far longer than smaller models.
- 100% Passive & Zero Cost — No electricity, no pumps, no filters, no service bills — environmentally and financially sustainable.
- Patented CAD2 Diaphragm — Ensures even pressure delivery, prevents waterlogging, and maximises effective storage.
- Corrosion-Proof Composite — Fibreglass/epoxy construction outperforms steel in longevity and weight (35 kg empty).
- Scalable for Bigger Sites — Parallel multiple units for hotels, care homes or multi-occupancy buildings.
- WRAS Hygienic & Compliant — Butyl membrane (WRAS 1501305) safe for potable systems; meets UK water regulations.
- No Noise Ever — Completely silent (0 dB) — ideal for residential or noise-sensitive commercial settings.
Key Features
Technical Specifications
| Specification | Value |
|---|---|
| Part Number | 11007353 |
| Total Vessel Volume | 350 litres |
| Usable Water Volume | ~175 litres (at 1.5 bar differential) |
| Dimensions (Ø × Height – vertical only) | 614 × 1448 mm |
| Empty Weight | 35 kg |
| Full Weight (approx.) | 210 kg |
| Connections | 1¼" BSP male × 28 mm compression |
| Max Working Pressure | 8.6 bar (860 kPa) |
| Pre-charge Pressure | 1.4 bar (factory — adjustable) |
| Max Boost Head (closed valve) | 4.3 bar |
| Water Temperature Range | 4 °C to 35 °C |
| Ambient Temperature Max | 40 °C |
| Membrane Material | Butyl rubber (WRAS 1501305) |
| Tank Construction | Continuous strand fibreglass + epoxy resin |
| Warranty | 5 years (vessel & diaphragm) |
What's in the Box
✅ Must-have accessories: Upstream Kit 22/28 mm (11007380) for first unit + Add-on Kit (11007327) per extra accumulator. For very low incoming pressure add Charger Pump (11007348). Vertical mount only — no horizontal cradle available for this model.
Frequently Asked Questions
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OSO Acc350 SuperStream 350L Cold Water Accumulator Tank
OSO Acc350 SuperStream 350 L Accumulator — Extra-large power-free cold water accumulator tank booster with patented CAD2 diaphragm technology | Up to ~80 l/min extra flow | Silent, zero-energy, zero-maintenance | ~175 L usable volume | Vertical install only | WRAS-approved butyl membrane | 5-year warranty | Ideal for large homes, guest houses or light commercial
The OSO SuperStream Acc350 is the heavy-duty vertical accumulator built for properties with exceptional simultaneous demand — larger family homes, bed & breakfasts, small care facilities or light commercial setups where 3–5+ outlets may run at once. With 350 litres total volume and around 175 litres of usable stored water (at 1.5 bar differential), it offers the longest buffer of boosted performance before relying purely on incoming mains supply.
Powered solely by mains pressure via the patented CAD2 diaphragm system, it delivers silent, maintenance-free flow supplementation of up to ~80 litres per minute with zero electricity consumption, zero noise and zero ongoing costs. The robust composite fiberglass/epoxy shell is corrosion-resistant, weighs only 35 kg empty (much lighter than equivalent steel vessels), and is designed for long-term reliability in demanding environments.
This model is vertical-mount only (no horizontal cradle option), making it best suited to taller spaces such as plant rooms, garages or dedicated cupboards. Like all SuperStream units, it requires no annual servicing and continues to function perfectly during power outages — a true "fit and forget" solution.
What Makes the SuperStream Acc350 Special?
- Maximum Domestic/Commercial Reserve — ~175 L usable volume — sustains high flow far longer than smaller models.
- 100% Passive & Zero Cost — No electricity, no pumps, no filters, no service bills — environmentally and financially sustainable.
- Patented CAD2 Diaphragm — Ensures even pressure delivery, prevents waterlogging, and maximises effective storage.
- Corrosion-Proof Composite — Fibreglass/epoxy construction outperforms steel in longevity and weight (35 kg empty).
- Scalable for Bigger Sites — Parallel multiple units for hotels, care homes or multi-occupancy buildings.
- WRAS Hygienic & Compliant — Butyl membrane (WRAS 1501305) safe for potable systems; meets UK water regulations.
- No Noise Ever — Completely silent (0 dB) — ideal for residential or noise-sensitive commercial settings.
Key Features
Technical Specifications
| Specification | Value |
|---|---|
| Part Number | 11007353 |
| Total Vessel Volume | 350 litres |
| Usable Water Volume | ~175 litres (at 1.5 bar differential) |
| Dimensions (Ø × Height – vertical only) | 614 × 1448 mm |
| Empty Weight | 35 kg |
| Full Weight (approx.) | 210 kg |
| Connections | 1¼" BSP male × 28 mm compression |
| Max Working Pressure | 8.6 bar (860 kPa) |
| Pre-charge Pressure | 1.4 bar (factory — adjustable) |
| Max Boost Head (closed valve) | 4.3 bar |
| Water Temperature Range | 4 °C to 35 °C |
| Ambient Temperature Max | 40 °C |
| Membrane Material | Butyl rubber (WRAS 1501305) |
| Tank Construction | Continuous strand fibreglass + epoxy resin |
| Warranty | 5 years (vessel & diaphragm) |
What's in the Box
✅ Must-have accessories: Upstream Kit 22/28 mm (11007380) for first unit + Add-on Kit (11007327) per extra accumulator. For very low incoming pressure add Charger Pump (11007348). Vertical mount only — no horizontal cradle available for this model.
Frequently Asked Questions
Product Information
Product Information
Shipping & Returns
Shipping & Returns
Description
OSO Acc350 SuperStream 350 L Accumulator — Extra-large power-free cold water accumulator tank booster with patented CAD2 diaphragm technology | Up to ~80 l/min extra flow | Silent, zero-energy, zero-maintenance | ~175 L usable volume | Vertical install only | WRAS-approved butyl membrane | 5-year warranty | Ideal for large homes, guest houses or light commercial
The OSO SuperStream Acc350 is the heavy-duty vertical accumulator built for properties with exceptional simultaneous demand — larger family homes, bed & breakfasts, small care facilities or light commercial setups where 3–5+ outlets may run at once. With 350 litres total volume and around 175 litres of usable stored water (at 1.5 bar differential), it offers the longest buffer of boosted performance before relying purely on incoming mains supply.
Powered solely by mains pressure via the patented CAD2 diaphragm system, it delivers silent, maintenance-free flow supplementation of up to ~80 litres per minute with zero electricity consumption, zero noise and zero ongoing costs. The robust composite fiberglass/epoxy shell is corrosion-resistant, weighs only 35 kg empty (much lighter than equivalent steel vessels), and is designed for long-term reliability in demanding environments.
This model is vertical-mount only (no horizontal cradle option), making it best suited to taller spaces such as plant rooms, garages or dedicated cupboards. Like all SuperStream units, it requires no annual servicing and continues to function perfectly during power outages — a true "fit and forget" solution.
What Makes the SuperStream Acc350 Special?
- Maximum Domestic/Commercial Reserve — ~175 L usable volume — sustains high flow far longer than smaller models.
- 100% Passive & Zero Cost — No electricity, no pumps, no filters, no service bills — environmentally and financially sustainable.
- Patented CAD2 Diaphragm — Ensures even pressure delivery, prevents waterlogging, and maximises effective storage.
- Corrosion-Proof Composite — Fibreglass/epoxy construction outperforms steel in longevity and weight (35 kg empty).
- Scalable for Bigger Sites — Parallel multiple units for hotels, care homes or multi-occupancy buildings.
- WRAS Hygienic & Compliant — Butyl membrane (WRAS 1501305) safe for potable systems; meets UK water regulations.
- No Noise Ever — Completely silent (0 dB) — ideal for residential or noise-sensitive commercial settings.
Key Features
Technical Specifications
| Specification | Value |
|---|---|
| Part Number | 11007353 |
| Total Vessel Volume | 350 litres |
| Usable Water Volume | ~175 litres (at 1.5 bar differential) |
| Dimensions (Ø × Height – vertical only) | 614 × 1448 mm |
| Empty Weight | 35 kg |
| Full Weight (approx.) | 210 kg |
| Connections | 1¼" BSP male × 28 mm compression |
| Max Working Pressure | 8.6 bar (860 kPa) |
| Pre-charge Pressure | 1.4 bar (factory — adjustable) |
| Max Boost Head (closed valve) | 4.3 bar |
| Water Temperature Range | 4 °C to 35 °C |
| Ambient Temperature Max | 40 °C |
| Membrane Material | Butyl rubber (WRAS 1501305) |
| Tank Construction | Continuous strand fibreglass + epoxy resin |
| Warranty | 5 years (vessel & diaphragm) |
What's in the Box
✅ Must-have accessories: Upstream Kit 22/28 mm (11007380) for first unit + Add-on Kit (11007327) per extra accumulator. For very low incoming pressure add Charger Pump (11007348). Vertical mount only — no horizontal cradle available for this model.
