OSO Delta A-Rated 300L Pre-plumbed Indirect Unvented Hot Water Cylinder DC300PP
The OSO Delta DC300PP is an ErP A-rated, pre-plumbed indirect unvented hot water cylinder at 300 litres — the largest capacity in OSO's award-winning Delta series. It achieves its Class A energy rating through a combination of Vacuum Insulation Panels (VIPs) and 4th-generation polyurethane foam — a world first across a full capacity range. The pre-plumbed (PP) configuration saves up to 70% of installation labour thanks to its factory-assembled integral expansion vessel and cold-feed assembly. At 595 mm diameter × 1745 mm height and 58 kg empty, it is significantly shorter than most 300-litre competitors, producing the same volume of hot water in a more airing-cupboard-friendly footprint. Suited to large family homes, HMOs, developer new-builds and any installation where hot water demand is high and energy efficiency is paramount.
The OSO Delta is unique in achieving ErP Class A across its full capacity range. This is made possible by combining Vacuum Insulation Panels (VIPs) — a technology borrowed from cryogenic engineering — with 4th-generation polyurethane foam. The result is dramatically lower standing heat loss than any C-rated competitor: saving approximately 1 kWh per day in the popular 210 L size versus a C-rated cylinder. Over a year, that is meaningful energy and cost saving for every household.
The Delta series is industry award-winning and recognised as the most energy-efficient unvented hot water cylinder range available. OSO cylinders are shorter than most competitors at equivalent volume — producing up to 20% more hot water per unit of height. This means you can often downsize the floor plan footprint when switching to OSO without losing capacity.
The DC pre-plumbed (PP) configuration includes an integral expansion vessel and pre-fitted cold-feed assembly — saving up to 70% of installation labour compared to an unplumbed cylinder requiring separate component fitting. This makes the DC PP particularly popular with housebuilders, developers and new-build programmes where installation speed and repeatability matter.
The OSO Delta is supplied with a digital adjustable thermostat (20–70 °C, preset 60 °C) with built-in anti-legionella pasteurisation and holiday mode. The anti-legionella cycle automatically heats the cylinder to above 60 °C at set intervals to suppress Legionella bacteria — a requirement under HSG274 guidance for commercial and multi-occupancy buildings.
The pre-plumbed kit includes a Honeywell V4043H 2-port motorised valve — a market-standard, widely-stocked component that installers and service engineers are familiar with. If a valve ever needs replacement, sourcing is straightforward from any plumbing merchant. The full G3 kit is included: strainer, PRV, expansion relief valve, drain cock, tundish, T&P relief valve (10 bar / 90–95 °C).
The cylinder sits on factory-fitted adjustable feet, making it straightforward to level on uneven plant room floors without shimming. The feet also raise the cylinder slightly off the floor, helping to protect against damp and making inspection of the base easier during annual servicing.
| Parameter | Value |
|---|---|
| Model / MPN | DC300PP |
| Capacity | 300 L |
| ErP energy rating | A |
| Dimensions (H × D) | 1745 mm × 595 mm |
| Weight (empty) | 58 kg |
| Weight (full, approx) | ~358 kg |
| Recovery time | 37 minutes |
| Max working pressure | 10 bar |
| T&P relief valve | 10 bar / 90–95 °C |
| Thermostat | Digital, adjustable 20–70 °C, preset 60 °C |
| Motorised valve | Honeywell V4043H1056C 2-port |
| Expansion vessel | 12–24 L (included, integral to pre-plumbed assembly) |
| Insulation technology | Vacuum Insulation Panels + 4th-generation PU foam |
| Connections | 28 mm |
| Pre-plumbed | Yes — integral expansion vessel, cold-feed assembly |
| Feet | Adjustable — factory fitted |
What makes the OSO Delta A-rated when most cylinders are C-rated?
What is the difference between the pre-plumbed (PP) and standard (unplumbed) Delta?
Who must install an unvented hot water cylinder?
Is the OSO Delta compatible with heat pumps?
Does the OSO Delta need annual servicing?
Original: $2,621.06
-65%$2,621.06
$917.37More Images
OSO Delta A-Rated 300L Pre-plumbed Indirect Unvented Hot Water Cylinder DC300PP
The OSO Delta DC300PP is an ErP A-rated, pre-plumbed indirect unvented hot water cylinder at 300 litres — the largest capacity in OSO's award-winning Delta series. It achieves its Class A energy rating through a combination of Vacuum Insulation Panels (VIPs) and 4th-generation polyurethane foam — a world first across a full capacity range. The pre-plumbed (PP) configuration saves up to 70% of installation labour thanks to its factory-assembled integral expansion vessel and cold-feed assembly. At 595 mm diameter × 1745 mm height and 58 kg empty, it is significantly shorter than most 300-litre competitors, producing the same volume of hot water in a more airing-cupboard-friendly footprint. Suited to large family homes, HMOs, developer new-builds and any installation where hot water demand is high and energy efficiency is paramount.
The OSO Delta is unique in achieving ErP Class A across its full capacity range. This is made possible by combining Vacuum Insulation Panels (VIPs) — a technology borrowed from cryogenic engineering — with 4th-generation polyurethane foam. The result is dramatically lower standing heat loss than any C-rated competitor: saving approximately 1 kWh per day in the popular 210 L size versus a C-rated cylinder. Over a year, that is meaningful energy and cost saving for every household.
The Delta series is industry award-winning and recognised as the most energy-efficient unvented hot water cylinder range available. OSO cylinders are shorter than most competitors at equivalent volume — producing up to 20% more hot water per unit of height. This means you can often downsize the floor plan footprint when switching to OSO without losing capacity.
The DC pre-plumbed (PP) configuration includes an integral expansion vessel and pre-fitted cold-feed assembly — saving up to 70% of installation labour compared to an unplumbed cylinder requiring separate component fitting. This makes the DC PP particularly popular with housebuilders, developers and new-build programmes where installation speed and repeatability matter.
The OSO Delta is supplied with a digital adjustable thermostat (20–70 °C, preset 60 °C) with built-in anti-legionella pasteurisation and holiday mode. The anti-legionella cycle automatically heats the cylinder to above 60 °C at set intervals to suppress Legionella bacteria — a requirement under HSG274 guidance for commercial and multi-occupancy buildings.
The pre-plumbed kit includes a Honeywell V4043H 2-port motorised valve — a market-standard, widely-stocked component that installers and service engineers are familiar with. If a valve ever needs replacement, sourcing is straightforward from any plumbing merchant. The full G3 kit is included: strainer, PRV, expansion relief valve, drain cock, tundish, T&P relief valve (10 bar / 90–95 °C).
The cylinder sits on factory-fitted adjustable feet, making it straightforward to level on uneven plant room floors without shimming. The feet also raise the cylinder slightly off the floor, helping to protect against damp and making inspection of the base easier during annual servicing.
| Parameter | Value |
|---|---|
| Model / MPN | DC300PP |
| Capacity | 300 L |
| ErP energy rating | A |
| Dimensions (H × D) | 1745 mm × 595 mm |
| Weight (empty) | 58 kg |
| Weight (full, approx) | ~358 kg |
| Recovery time | 37 minutes |
| Max working pressure | 10 bar |
| T&P relief valve | 10 bar / 90–95 °C |
| Thermostat | Digital, adjustable 20–70 °C, preset 60 °C |
| Motorised valve | Honeywell V4043H1056C 2-port |
| Expansion vessel | 12–24 L (included, integral to pre-plumbed assembly) |
| Insulation technology | Vacuum Insulation Panels + 4th-generation PU foam |
| Connections | 28 mm |
| Pre-plumbed | Yes — integral expansion vessel, cold-feed assembly |
| Feet | Adjustable — factory fitted |
What makes the OSO Delta A-rated when most cylinders are C-rated?
What is the difference between the pre-plumbed (PP) and standard (unplumbed) Delta?
Who must install an unvented hot water cylinder?
Is the OSO Delta compatible with heat pumps?
Does the OSO Delta need annual servicing?
Product Information
Product Information
Shipping & Returns
Shipping & Returns
Description
The OSO Delta DC300PP is an ErP A-rated, pre-plumbed indirect unvented hot water cylinder at 300 litres — the largest capacity in OSO's award-winning Delta series. It achieves its Class A energy rating through a combination of Vacuum Insulation Panels (VIPs) and 4th-generation polyurethane foam — a world first across a full capacity range. The pre-plumbed (PP) configuration saves up to 70% of installation labour thanks to its factory-assembled integral expansion vessel and cold-feed assembly. At 595 mm diameter × 1745 mm height and 58 kg empty, it is significantly shorter than most 300-litre competitors, producing the same volume of hot water in a more airing-cupboard-friendly footprint. Suited to large family homes, HMOs, developer new-builds and any installation where hot water demand is high and energy efficiency is paramount.
The OSO Delta is unique in achieving ErP Class A across its full capacity range. This is made possible by combining Vacuum Insulation Panels (VIPs) — a technology borrowed from cryogenic engineering — with 4th-generation polyurethane foam. The result is dramatically lower standing heat loss than any C-rated competitor: saving approximately 1 kWh per day in the popular 210 L size versus a C-rated cylinder. Over a year, that is meaningful energy and cost saving for every household.
The Delta series is industry award-winning and recognised as the most energy-efficient unvented hot water cylinder range available. OSO cylinders are shorter than most competitors at equivalent volume — producing up to 20% more hot water per unit of height. This means you can often downsize the floor plan footprint when switching to OSO without losing capacity.
The DC pre-plumbed (PP) configuration includes an integral expansion vessel and pre-fitted cold-feed assembly — saving up to 70% of installation labour compared to an unplumbed cylinder requiring separate component fitting. This makes the DC PP particularly popular with housebuilders, developers and new-build programmes where installation speed and repeatability matter.
The OSO Delta is supplied with a digital adjustable thermostat (20–70 °C, preset 60 °C) with built-in anti-legionella pasteurisation and holiday mode. The anti-legionella cycle automatically heats the cylinder to above 60 °C at set intervals to suppress Legionella bacteria — a requirement under HSG274 guidance for commercial and multi-occupancy buildings.
The pre-plumbed kit includes a Honeywell V4043H 2-port motorised valve — a market-standard, widely-stocked component that installers and service engineers are familiar with. If a valve ever needs replacement, sourcing is straightforward from any plumbing merchant. The full G3 kit is included: strainer, PRV, expansion relief valve, drain cock, tundish, T&P relief valve (10 bar / 90–95 °C).
The cylinder sits on factory-fitted adjustable feet, making it straightforward to level on uneven plant room floors without shimming. The feet also raise the cylinder slightly off the floor, helping to protect against damp and making inspection of the base easier during annual servicing.
| Parameter | Value |
|---|---|
| Model / MPN | DC300PP |
| Capacity | 300 L |
| ErP energy rating | A |
| Dimensions (H × D) | 1745 mm × 595 mm |
| Weight (empty) | 58 kg |
| Weight (full, approx) | ~358 kg |
| Recovery time | 37 minutes |
| Max working pressure | 10 bar |
| T&P relief valve | 10 bar / 90–95 °C |
| Thermostat | Digital, adjustable 20–70 °C, preset 60 °C |
| Motorised valve | Honeywell V4043H1056C 2-port |
| Expansion vessel | 12–24 L (included, integral to pre-plumbed assembly) |
| Insulation technology | Vacuum Insulation Panels + 4th-generation PU foam |
| Connections | 28 mm |
| Pre-plumbed | Yes — integral expansion vessel, cold-feed assembly |
| Feet | Adjustable — factory fitted |
