Trustpilot

iS System Boiler

i15S i18S i24S i32S i40S

Every ATAG boiler carries a 12-year warranty as standard, with an option of 18 years!

With output sizes of 15kW, 18kW, 24kW, 32kW and 40kW, the compact casing of the iS range houses an outstandingly efficient boiler that offers excellent, low-maintenance performance and is easy to install.

Furthermore, we have made these easy for homeowners to operate. With the addition of a 3 port valve kit, the iS system boilers can be controlled using an ATAG ONE Zone or Tado V3+ smart controller. 

Get a quote User manual Installation & Servicing Key Features Specification

Key features and benefits

compact

Compact dimensions

h700 x w440 x d366 (mm)

models

Five models available

15kW, 18kW, 24kW, 32kW, 40kW

warranty

Up to 18 years warranty

Including all parts and labour

user-friendly

Completely user friendly

with intuitive controls

no-sound

Quiet in operation

Due to bottom-up modulation

snow

Frost protection

With built-in frost protection

erp-a

ErP "A" rated

Achieves ErP ‘A’ rating for heating and hot water

loved

Loved by customers

ATAG is the UK’s highest rated boiler brand on Trustpilot

  • A 275 mm (deep) model is available to fit inside kitchen cupboards
  • 12 years warranty as standard with options up to 18 years
  • ATAG iCon stainless steel heat exchanger – with its unique lifetime replacement guarantee
  • Supplied with fixing jig as standard, for rear piping up behind the boiler
  • Combined condensate and pressure relief valve outlet pipe means less pipework
  • Detailed fault codes on LCD display for quicker, more accurate boiler diagnostics
  • Fully compatible with ATAG iSteel cylinder range & the 3 port valve kit
  • Fully compatible with solar thermal hot water systems and ATAG iSteel twin coil cylinder range
  • Factory fitted ErP-ready pump for low electrical consumption and improved efficiency
  • Control the system via smartphone using the ATAG ONE or Tado V3+ smart controller
  • Built-in anti-cycling function for improved efficiency

Specifications

i15S
i18S
i24S
i32S
i40S

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PART NUMBER

BS300315

ERP SEASONAL SPACE HEATING ENERGY EFFICIENCY CLASS

A

ERP SEASONAL SPACE HEATING ENERGY EFFICIENCY (%)

93

CH OUTPUT KW (50/30°C)

14.7

SEDBUK 2009 (%)

89.8

DIMENSIONS (H X W X D) MM

700X440X355

BOILER LIFT WEIGHT WITH JIG (KG)

39

STANDARD WARRANTY (YEARS)

10

LPG CONVERSION KIT AVAILABLE

YES

NOX CLASS

6

INGRESS PROTECTION (IP)

IPPX4D

MAXIMUM EQUIVALENT HORIZONTAL/VERTICAL FLUE LENGTH (M) 60/100MM

18

MAXIMUM EQUIVALENT HORIZONTAL/VERTICAL FLUE LENGTH (M) 80/125MM

50

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PART NUMBER

BS300318

ERP SEASONAL SPACE HEATING ENERGY EFFICIENCY CLASS

A

ERP SEASONAL SPACE HEATING ENERGY EFFICIENCY (%)

93

CH OUTPUT KW (50/30°C)

17.5

SEDBUK 2009 (%)

89.8

DIMENSIONS (H X W X D) MM

700X440X355

BOILER LIFT WEIGHT WITH JIG (KG)

39

STANDARD WARRANTY (YEARS)

10

LPG CONVERSION KIT AVAILABLE

YES

NOX CLASS

6

INGRESS PROTECTION (IP)

IPPX4D

MAXIMUM EQUIVALENT HORIZONTAL/VERTICAL FLUE LENGTH (M) 60/100MM

18

MAXIMUM EQUIVALENT HORIZONTAL/VERTICAL FLUE LENGTH (M) 80/125MM

50

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PART NUMBER

BS300324

ERP SEASONAL SPACE HEATING ENERGY EFFICIENCY CLASS

A

ERP SEASONAL SPACE HEATING ENERGY EFFICIENCY (%)

94

CH OUTPUT KW (50/30°C)

23.2

SEDBUK 2009 (%)

89.8

DIMENSIONS (H X W X D) MM

700X440X355

BOILER LIFT WEIGHT WITH JIG (KG)

39

STANDARD WARRANTY (YEARS)

10

LPG CONVERSION KIT AVAILABLE

YES

NOX CLASS

6

INGRESS PROTECTION (IP)

IPPX4D

MAXIMUM EQUIVALENT HORIZONTAL/VERTICAL FLUE LENGTH (M) 60/100MM

18

MAXIMUM EQUIVALENT HORIZONTAL/VERTICAL FLUE LENGTH (M) 80/125MM

50

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PART NUMBER

BS300332

ERP SEASONAL SPACE HEATING ENERGY EFFICIENCY CLASS

A

ERP SEASONAL SPACE HEATING ENERGY EFFICIENCY (%)

94

CH OUTPUT KW (50/30°C)

31.2

SEDBUK 2009 (%)

89.8

DIMENSIONS (H X W X D) MM

700X440X355

BOILER LIFT WEIGHT WITH JIG (KG)

42

STANDARD WARRANTY (YEARS)

10

LPG CONVERSION KIT AVAILABLE

YES

NOX CLASS

6

INGRESS PROTECTION (IP)

IPPX4D

MAXIMUM EQUIVALENT HORIZONTAL/VERTICAL FLUE LENGTH (M) 60/100MM

18

MAXIMUM EQUIVALENT HORIZONTAL/VERTICAL FLUE LENGTH (M) 80/125MM

45

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PART NUMBER

BS300340

ERP SEASONAL SPACE HEATING ENERGY EFFICIENCY CLASS

A

ERP SEASONAL SPACE HEATING ENERGY EFFICIENCY (%)

94

CH OUTPUT KW (50/30°C)

38.8

SEDBUK 2009 (%)

89.8

DIMENSIONS (H X W X D) MM

700X440X355

BOILER LIFT WEIGHT WITH JIG (KG)

42

STANDARD WARRANTY (YEARS)

10

LPG CONVERSION KIT AVAILABLE

YES

NOX CLASS

6

INGRESS PROTECTION (IP)

IPPX4D

MAXIMUM EQUIVALENT HORIZONTAL/VERTICAL FLUE LENGTH (M) 60/100MM

18

MAXIMUM EQUIVALENT HORIZONTAL/VERTICAL FLUE LENGTH (M) 80/125MM

45

OneZone (3)-1

OneZone

Control the temperature in your home remotely using the ATAG One Zone App, available for FREE on the App Store or Google Play.

View the OneZone
Cylinders

Cylinders

Need replacement cylinders? Check out our range to see which one each boiler requires.

View all cylinders
Flyer Water Treatment Pack

Chemicals and filters

We have a range of chemicals and filters that can be used with our boilers.

View all filters and chemicals

Interested in becoming a ATAG Selected Partner?

If you're interested in becoming a ATAG Selected Partner, simply click on the button below to submit your form. If you'd like more information about our boilers, why not book a demo below?

Become a registered installer     Book a product demo