Potterton Promax SL Heat

The Potterton Promax SL Heat is a first-class, heat-only boiler that is suitable for both new build or replacement installations.

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Suitable for

Social Housing

New Builds

Single boiler output
12kW, 15kW, 18kW and 24kW

Compact and light
Can be installed in a standard kitchen cupboard

No pump overrun
Quicker installation time for end user

Available in the choice of four outputs of 12kW, 15kW, 18kW and 24kW, the Promax SL Heat is small enough to fit in a standard kitchen unit and light enough for quick and easy installation.

The Potterton Promax SL Heat is a highly efficient heating solution with an excellent SAP 2012 rating and comes with a 2 year warranty as standard for complete peace of mind*. Installation can be made even faster with the use of a simple mounting plate, and is class 5 NOx as standard.

You can register your Potterton boiler online using Baxi's warranty registration form.

Terms and conditions apply.

Please note: warranty and purchasing information on this site applies to the UK only. For information on how to buy these products in the Republic of Ireland, please visit Baxi Potterton Myson.

Get in touch
  • 12kW, 15kW, 18kW, 24kW outputs available - a model to suit most sizes of property
  • N0x Class 5 - best in class
  • Compact and light -  can be installed in a standard kitchen unit
  • Simple mounting plate - for a quick and easy installation
  • No pump overrun - shortening installation time further
  • Pre-plumbing jig -  saving time on installation
  • Compatible with Megaflo Eco Solar Cylinder

View product specification

When clicked this will open the product specification in PDF format.

Potterton Promax SL Heat

Units  12 15 18 24
Sales code 7219398 7219399 7219400 7219401


Reset button   Yes  Yes  Yes  Yes 


Gas (natural gas/LPG) NG NG NG NG
Inlet supply pressure mbar 20  20  20  20 
Maximum gas rate  m3/hr  1.34 1.64 1.94 2.31
Heat input central heating (CH)  kW Max Gross (QnHs)  13.34 16.88 20.18 24.5
kW Min Gross (QnHs)  10.2 10.2 10.2 10.2
Heat output CH non-condensing  kW Max (Pn)  11.82  15.24 17.81 22
kW min (Pn)  9.14 9.14 9.14 9.14
Heat output CH condensing 

kW max (Pnc) 

12.81 16.49 19.27 23.8
SAP 2009/2012 annual efficiency (PCDB/SEDBUK)  88.7 89.4 88.7  88.8 
NOx class   

ErP product information 

NOx  mg/kWh  20 20 20 19 
Sound power level, indoors  LwaDB  38  46  49  52 
Space heating efficiency class   
EcoHomes    3


Electrical supply  Volts/Hz  230/50  230/50  230/50  230/50 
Permanent live required  No No No No
Power consumption  Watts  80 80 80 80
External fuse rating  Amps 
Boiler IPX rating (electrical protection)   IPX2  IPX2  IPX2  IPX2 
Integral 'boiler only' frost thermostat    No No No No


Gas supply connection  inch 1/2 1/2 1/2 1/2
Central heating connections  mm  22  22  22  22 
Condensate drain connection  inch 1.0 1.0 1.0 1.0
Upward piping route mm  Yes   Yes   Yes   Yes  


Compartment ventilation required   No  No  No  No

Concentric flue systems 

 Concentric flue diameters   70/110  
Concentric standard flue length mm  800 800 800 800
Max equiv vertical length (ø70/110)  4 4 4 4
Max equiv horizontal length (ø70/110)  4 4 4 4

Twin flue system 

Twin flue pipe diameter  mm  80/80 80/80 80/80 80/80
Max equiv length vertical length  75 75 75 75
Max equiv length horizontal length   75 75 75 75

Plume displacement kit 

Compatibility  ✓  ✓  ✓  ✓ 


Gross packaged boiler weight  kg 36.2  36.2  36.2  36.2 
Max installation lift weight  kg  26 26 26 26
Packaged boiler dimensions (WxHxDxSCxUCxLCxFC)   390mm x 600mm x 280mm x 5mm x 200mm x 50mm x 5mm (500mm for servicing) 

Promax SL heat literature

Potterton Promax Range Guide updated 17/05/2017 (15.43MB) Tenants leaflet example updated 30/06/2017 (3.90MB) Promax SL user guide updated 24/10/2016 (0.87MB) Promax SL installation and servicing manual updated 24/10/2016 (3.79MB)

The following accessories and controls are compatible with the Potterton Promax SL Heat. To find out more, visit our Accessories and Controls page.

  • EP1 Programmer
  • EP2 Programmer
  • Multifit condensate trace heating kit 1m
  • Multifit condensate trace heating kit 2m
  • Multifit condensate trace heating kit 3m 
  • Multifit condensate trace heating kit 5m 
  • Multifit external boiler discharge pump (prv and condensate)

Promax SL Heat ErP labels

Promax SL ErP label updated 08/04/2016 (0.14MB) Product fiche Potterton Promax Heat updated 09/09/2015 (0.11MB)

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