The Heatrae Sadia Megaflo Eco Direct DDDD is the most powerful electrically heated variant in the Megaflo Eco range — fitted with four 3 kW titanium immersion heaters (12 kW total) for the fastest possible electric heat-up and maximum off-peak tariff flexibility. Available in 210, 250, and 300 litres, these cylinders share identical vessel dimensions and specifications with the DD and DDD variants — only the element count changes. Every model delivers mains-pressure hot water at up to 76 l/min at 3 bar, uses the same internal expansion system, and carries a lifetime inner-tank guarantee.
51–73 min
Full heat-up (12 kW)
76 l/min
Max flow at 3 bar
Lifetime
Inner-tank guarantee
⚠ G3 Competent Person & Qualified Electrician — 12 kW Load
DDDD cylinders must be installed by a G3 accredited competent person. All electrical connections must be made by a qualified electrician. With up to 12 kW of installed element load, the electrical installation requires careful circuit design — individual elements typically each require their own dedicated fused spur or MCB-protected circuit. Confirm supply capacity and cable sizing with your electrician before ordering.
ℹ Direct (electrically heated) — no boiler connection
DDDD models are heated exclusively by their four 3 kW titanium immersion heaters. There is no boiler coil. Designed for all-electric homes, air-source heat pump diverter applications (e.g. paired with a myenergi Eddi), Economy 7/10 installations, and high-demand properties requiring maximum electric hot water capacity. For boiler-fed cylinders, see the Megaflo Eco Indirect range.
ℹ The fastest electric heat-up in the Megaflo Eco Direct range
The DDDD's 12 kW total capacity delivers the fastest cylinder heat-up available in the Megaflo Eco Direct family: 210DDDD in 51 min, 250DDDD in 60 min, 300DDDD in 73 min — compared to 68/81/97 min for DDD and 102/121/146 min for DD. Four separately controllable elements also allow the most sophisticated off-peak tariff configurations, including multiple time bands on a single cylinder.
KEY FEATURES
Four Titanium Immersions — 12 kW Total
Four independently controlled 3 kW titanium immersion heaters provide the maximum installed electric capacity in the Megaflo Eco Direct range. Titanium elements are specified for their outstanding longevity in aggressive, hard, or corrosive water — significantly outperforming standard Incoloy or stainless steel alternatives over a cylinder's lifespan.
Fastest Megaflo Electric Heat-Up
Running all four elements simultaneously at 12 kW gives the fastest full-cylinder heat-up in the entire Megaflo Eco Direct range: 51 minutes (210L), 60 minutes (250L), 73 minutes (300L). For comparison, the equivalent DDD models take 68, 81, and 97 minutes; DD models take 102, 121, and 146 minutes. Critical for large properties where overnight off-peak charging time is limited.
Maximum Off-Peak Tariff Flexibility
Four independently wired elements allow up to four separate time-band or tariff configurations on a single cylinder — ideal for Economy 10 (three off-peak periods), solar PV diverter integration (e.g. myenergi Eddi), and smart energy management systems that optimise immersion switching based on grid carbon intensity or time-of-use pricing.
Internal Expansion — No External DHW Vessel
Identical to all Megaflo Eco models, the DDDD uses the patented internal floating-baffle expansion system — no external DHW expansion vessel is required. The same cylinder body dimensions as the DD and DDD variants mean the DDDD is a direct footprint-for-footprint upgrade when replacing an existing Megaflo.
Duplex Stainless Steel — Lifetime Guarantee
The same high-grade duplex stainless steel vessel, pressure-tested to 15 bar, as all Megaflo Eco cylinders. Heatrae Sadia back the inner vessel with a lifetime guarantee for domestic first-owner installations. All components carry a 2-year warranty. Manufactured in the UK under BS EN ISO 9001, ISO 14001, ISO 50001 and OHSAS 18001.
76 l/min Mains Pressure — Full Kit Supplied
All DDDD models deliver up to 76 l/min at 3 bar — identical flow performance to the DD and DDD. Every cylinder ships with the complete unvented safety pack: cold water inlet control kit, factory-fitted 90 °C / 10 bar T&P valve, tundish, and T&P insulation kit.
FULL SPECIFICATIONS — DDDD DIRECT VARIANTS
| Parameter |
Specification (all DDDD models) |
| Inner vessel |
High-grade duplex stainless steel — tested to 15 bar |
| Insulation |
60 mm CFC/HCFC-free fire-retardant PU foam (GWP = 3.1) |
| Immersion heaters |
4 × 3 kW titanium @ 240 V (2.8 kW @ 230 V) — 12 kW total |
| Operating pressure |
0.3 MPa (3 bar) |
| Max mains supply (to PRV) |
1.6 MPa (16 bar) |
| Pressure relief valve |
0.8 MPa (8 bar) |
| T&P valve |
90 °C / 1 MPa (10 bar) — factory-fitted |
| Connections |
22 mm compression / ¾" BSP |
| Max flow at 3 bar |
76 litres/min |
| Max flow at 1 bar |
45 litres/min |
| Diameter (all models) |
579 mm (Ø) |
| ErP class |
Class C (all DDDD models) |
| Kiwa certification |
No. 1608707 |
| Guarantee |
Lifetime inner tank · 2 years components |
| Country of manufacture |
United Kingdom |
| Model |
210DDDD |
250DDDD |
300DDDD |
| Product code |
95050476 |
95050477 |
95050478 |
| Nominal capacity (L) |
210 |
250 |
300 |
| Immersions (No. × kW) |
4 × 3 kW |
4 × 3 kW |
4 × 3 kW |
| Storage vol @ 3 bar (L) |
199 |
236 |
283 |
| V40 mixed at 40 °C (L) |
241 |
307 |
359 |
| ErP load profile |
L |
XL |
XL |
| ErP water heating efficiency (%) |
37.5 |
37.8 |
37.7 |
| Heat-up time (all 12 kW, min) |
51 |
60 |
73 |
| Standing heat loss (kWh/24h) |
1.42 |
1.61 |
1.69 |
| Annual electricity (kWh) |
2,731 |
3,513 |
4,476 |
| Weight empty (kg) |
40 |
48 |
58 |
| Weight full (kg) |
237 |
283 |
339 |
DIMENSIONS (mm) — identical to DDD variants
| Dimension |
210DDDD |
250DDDD |
300DDDD |
| A — DHW inlet |
414 |
414 |
414 |
| B — Cable entry lower |
275 |
275 |
275 |
| C — Cable entry upper |
801 |
1009 |
1313 |
| D — T&P relief valve |
1095 |
1323 |
1574 |
| E — Height |
1486 |
1738 |
2053 |
| F — Depth |
600 |
600 |
600 |
| G — Width / Ø |
579 |
579 |
579 |
FREQUENTLY ASKED QUESTIONS
How much faster is the DDDD than the DDD and DD?
Running all four 12 kW elements simultaneously, the DDDD range heats up in 51 min (210L), 60 min (250L), and 73 min (300L). The equivalent DDD models (9 kW) take 68, 81, and 97 minutes; DD models (6 kW) take 102, 121, and 146 minutes. The DDDD is approximately 25% faster than the DDD and 50% faster than the DD for a full cold start — critical for high-demand households or properties where the overnight off-peak window is short.
What electrical supply does a DDDD cylinder require?
With 4 × 3 kW elements at 240 V, the maximum simultaneous load is 12 kW / 50 A. In practice, elements are rarely all energised simultaneously — most installations wire elements to separate time switches or smart controllers so only 1–2 elements run at once. Each element draws approximately 12.5 A and should have its own dedicated fused spur or MCB-protected radial circuit. Your electrician must assess the available supply capacity and agree a wiring scheme with the G3 installer before commissioning.
Can a DDDD be used with a solar PV diverter such as a myenergi Eddi?
Yes — the DDDD is an excellent choice for solar PV diverter integration. A device like the myenergi Eddi diverts surplus solar generation to one or more immersion heaters rather than exporting it to the grid, effectively storing free solar energy as hot water. The DDDD's four elements give the diverter a wider range of power levels to match — for example, directing 3 kW to one element at low surplus, 6 kW to two at medium, and so on. The myenergi Eddi is sold separately and supports up to two immersion loads per unit.
Do the DDDD and DDD share the same cylinder body?
Yes — the 210DDDD, 210DDD, and 210DD are all the same physical cylinder body (1486 mm tall, 579 mm Ø). Only the number of immersion heater ports and fitted elements differs. This means the DDDD can be specified as a direct physical replacement for any existing DD or DDD of the same nominal capacity, subject to the electrical supply being adequate for the additional elements.
What guarantee does the Megaflo Eco DDDD carry?
Heatrae Sadia provide a lifetime guarantee on the inner duplex stainless steel vessel for domestic first-owner installations (30 years transferable). All components — immersion heaters, valves, controls — carry a 2-year warranty. Warranty validity requires correct G3 installation, annual servicing, and a completed Benchmark commissioning checklist.
