iS Boiler System

i15S i18S i24S i32S i40S

Every ATAG boiler carries a 10 years warranty as standard with options up to 14 years and they’re professionally installed by our ATAG Selected Partners.

With an ATAG iS system boiler you’ll be choosing one of the most energy efficient boilers in Europe and you’ll love its easy to operate simplicity too.

What makes our system boilers different, though, is the in-built ErP pump. This controls the heat given out by the boiler, ensuring your boiler is as energy efficient as possible, saving you money year-on-year.

System boilers are traditionally fitted with an unvented hot cylinder which provides an increased capacity of hot water. The fact that the pump and controls are contained within the boiler casing counts towards a simple and space saving solution.

Get a quote Manual Not sure which boiler you require? 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 14 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
  • 10 years warranty as standard with options up to 14 years
  • Control the system via smartphone or tablet using the ATAG ONE controller
  • ATAG iCon stainless steel heat exchanger – with its unique lifetime replacement guarantee
  • Detailed fault codes on LCD display for quicker, more accurate boiler diagnostics
  • Fully compatible with ATAG iSteel cylinder range & the 3 port valve kit
  • Built-in anti-cycling function for improved efficiency
  • Combined condensate and pressure relief valve outlet pipe means less pipework
  • Fully compatible with solar thermal hot water systems and ATAG iSteel twin coil cylinder range
  • Supplied with fixing jig as standard, for rear piping up behind the boiler
  • Factory fitted ErP-ready pump for low electrical consumption and improved efficiency

Specifications

Scroll to view more information

PART NUMBER

BS300158

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 FLUE LENGTH (M) 60/100MM

18

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

18

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

50

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

50

Scroll to view more information

PART NUMBER

BS300118

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 FLUE LENGTH (M) 60/100MM

18

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

18

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

50

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

50

Scroll to view more information

PART NUMBER

BS300124

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 FLUE LENGTH (M) 60/100MM

18

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

18

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

50

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

50

Scroll to view more information

PART NUMBER

BS300132

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 FLUE LENGTH (M) 60/100MM

6

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

6

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

45

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

45

Scroll to view more information

PART NUMBER

BS300140

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 FLUE LENGTH (M) 60/100MM

6

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

6

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

45

MAXIMUM EQUIVALENT 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

OneZone smart controller
Cyclinders

Cylinders

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

View all cylinders
14 year warranty neon No BG-1

Complete care

Ask your ATAG installer about the complete care pack, including the ONEZone smart controller to increase your standard warranty from 10 to 14 years.

Find out more

Installers that you can depend on

From design through to installation and after-care service, our ATAG selected gas-safe installers are on hand to offer you excellent advice and the best solution possible that suits your needs.

Find an installer