The JAB DUC IE Indirect is a compact, internal-expansion unvented hot water cylinder heated from a gas or oil boiler, or a renewable heat source, with a factory-fitted 3kW immersion providing independent back-up. Available in six capacities from 120L to 300L, it's constructed from duplex stainless-steel, and because the expansion volume is built in, there's no external expansion vessel to find wall space for. It is manufactured in Britain.
550mm
Diameter (All Sizes)
1 x 3kW
Back-Up Immersion
10 bar / 90°C
T&P Relief Setting
Internal
Expansion Design
Installer requirement: this is an unvented hot water cylinder and must be installed, commissioned, and notified to Building Control by a G3-qualified (Benchmark) installer in line with Building Regulations Part G3.
Note on stated capacity range: JAB's marketing copy for this range advertises “90–300 litre capacities”, but no 90L model is currently listed for sale – the smallest size available is 120L. Confirm with JAB Products directly if a 90L unit is required.
All electrical connections, including the back-up immersion heater, must be wired by a qualified electrician in accordance with BS 7671; actual cable sizing should be calculated on site rather than assumed from generic figures.
Why Choose the JAB DUC IE Indirect
Internal Expansion Design
Building the expansion volume inside the cylinder removes the need for a separate external expansion vessel, simplifying installation and freeing up airing-cupboard space.
Duplex Stainless-Steel Shell
The duplex stainless-steel body resists pitting and stress corrosion far better than standard 304-grade tanks, giving reliable long-term performance in hard-water areas.
Boiler or Renewable Heat Source
The indirect coil connection lets the cylinder be heated by a gas or oil boiler, or a renewable heat source such as a heat pump, with the coil doing the day-to-day heavy lifting.
Independent Immersion Back-Up
A factory-fitted 3kW immersion heater gives an independent electric back-up route to hot water if the primary heat source is ever down.
Compact 550mm Diameter
A consistent 550mm diameter across the whole range keeps the footprint predictable when planning airing-cupboard space, whatever the capacity chosen.
Full Unvented Kit Included
The complete unvented kit ships with every cylinder, so the installer isn't left sourcing safety-group components separately.
Sizes & Pricing
| Capacity |
Dimensions (H x D) |
Back-Up Immersion |
Price |
| 120L |
925 x 550mm |
1 x 3kW |
£630.00 |
| 150L |
1125 x 550mm |
1 x 3kW |
£660.00 |
| 170L |
1225 x 550mm |
1 x 3kW |
£690.00 |
| 200L |
1425 x 550mm |
1 x 3kW |
£720.00 |
| 250L |
1725 x 550mm |
1 x 3kW |
£810.00 |
| 300L |
1950 x 550mm |
1 x 3kW |
£870.00 |
Technical Specification
| Construction |
| Cylinder Type |
Indirect, unvented, duplex stainless-steel, internal expansion |
| Coil & Fittings Grade |
316L stainless-steel |
| Manufacture |
Made in Britain |
| Note |
Actual water capacity is slightly less than the nominal litre rating due to the internal air gap |
| Connections & Safety (All Sizes) |
| Fittings |
22mm compression, 316L stainless-steel |
| Temperature & Pressure Relief Valve |
Factory-set 10 bar / 90°C |
| Expansion |
Internal – no external expansion vessel required |
| Heat Source |
Gas/oil boiler or renewable heat source, via internal coil |
| Unvented Kit |
Full kit supplied |
| Warranty |
| Inner Container |
Lifetime manufacturing warranty* |
| Components |
2 years* |
Frequently Asked Questions
What heat source does this cylinder use?
The internal coil is designed to be heated by a gas or oil-fired boiler, or a renewable heat source such as a heat pump, with the factory-fitted 3kW immersion providing independent electric back-up.
Do I still need an external expansion vessel?
No. The internal expansion design builds the expansion volume into the cylinder itself, so a separate wall-mounted expansion vessel isn't required, unlike JAB's Duc 2 external-expansion ranges.
How does this differ from the IE Direct range?
The IE Direct range has no boiler coil and relies entirely on immersion heaters, while this Indirect range is heated primarily by a boiler or renewable source, with a single immersion as back-up rather than the main heat source.
Does this cylinder need to be installed by a qualified installer?
Yes. As an unvented hot water cylinder it must be installed, commissioned, and notified to Building Control by a G3-qualified (Benchmark) installer in line with Building Regulations Part G3.
What T&P relief valve setting does this range use?
The factory-fitted temperature and pressure relief valve is set at 10 bar / 90°C, which is higher than JAB's external-expansion Duc 2 range (7 bar); check this against your system design.
What warranty does JAB provide?
JAB cylinders carry a lifetime manufacturing warranty on the inner container (2 years on components); confirm current terms and registration with JAB Products or your supplier at the time of purchase.
