The JAB DUC IE Indirect Slimline is a narrow-diameter, internal-expansion unvented hot water cylinder, built at just 480mm diameter for airing cupboards too tight for JAB's standard internal-expansion range. Available in four capacities from 120L to 200L, it's constructed from duplex stainless-steel, heated indirectly from a gas or oil boiler or renewable heat source, and backed up by a factory-fitted 3kW immersion heater. Because the expansion volume is built in, there's no external expansion vessel to find wall space for.
480mm
Diameter (All Sizes)
1 x 3kW
Back-Up Immersion
18.76–19.36kW
Coil Rating Range
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.
T&P relief valve pressure rating not specified: JAB's technical spec sheet for this range gives the temperature and pressure relief valve's fitting height on the cylinder but does not state its bar rating. Confirm the exact setting from the installation manual or with JAB Products before commissioning.
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 Slimline
Slim 480mm Diameter
At just 480mm diameter, this cylinder fits airing cupboards too narrow for JAB's standard 550mm-diameter internal-expansion range, without sacrificing the internal-expansion design.
Internal Expansion Design
Building the expansion volume inside the cylinder removes the need for a separate external expansion vessel, keeping the slim footprint free of extra wall-mounted components.
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 coil output rising from 18.76kW at 120L to 19.36kW at 200L.
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.
Full Unvented Kit Included
The complete unvented kit ships with every cylinder, so the installer isn't left sourcing safety-group components separately.
Sizes & Specification
| Capacity |
Height |
Coil Rating |
Standing Heat Loss |
ErP Band |
| 120L |
1250mm |
18.76kW |
1.37 kWh/24h |
C |
| 150L |
1525mm |
18.82kW |
1.60 kWh/24h |
C |
| 170L |
1700mm |
19.22kW |
1.70 kWh/24h |
C |
| 200L |
1950mm |
19.36kW |
1.80 kWh/24h |
C |
Connection Heights
| Capacity |
Cold Inlet |
Heating Flow |
Return |
Control Stat |
Immersion |
T&P Valve |
| 120L |
175mm |
200mm |
280mm |
350mm |
330mm |
820mm |
| 150L |
175mm |
200mm |
280mm |
350mm |
330mm |
1010mm |
| 170L |
175mm |
200mm |
280mm |
430mm |
410mm |
1110mm |
| 200L |
175mm |
200mm |
280mm |
430mm |
410mm |
1300mm |
Technical Specification
| Construction |
| Cylinder Type |
Indirect, unvented, duplex stainless-steel, slimline internal expansion |
| Diameter |
480mm (all sizes) |
| Energy Rating (ErP) |
C |
| Connections & Safety (All Sizes) |
| Expansion |
Internal – no external expansion vessel required |
| Immersion Heater |
1 x 3kW, factory-fitted (back-up) |
| 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 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.
How is this different from the standard JAB DUC IE Indirect range?
This Slimline version uses the same internal-expansion principle but in a narrower 480mm diameter shell (versus 550mm on the standard IE Indirect range), for tighter airing cupboards, with correspondingly taller cylinders at each capacity.
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.
How does the coil rating change across the range?
Coil output scales gently with capacity: 18.76kW at 120L, 18.82kW at 150L, 19.22kW at 170L, and 19.36kW at 200L, per JAB's technical spec sheet for this range.
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.
