Potterton Promax Combi

Designed to be installed with ease, the Potterton Promax Combi is the perfect combi boiler for new build and social housing projects. Contact your local Business Development Manager to find out more.

Contact your BDM
Suitable for

New Builds

Social Housing

Single boiler output
24kW, 28kW and 33kW

Robust hydraulic connections
For quality and reliability

Savings for end users
End users can see savings of up to 37% on gas for domestic hot water

The Potterton Promax Combi boiler has been designed specifically for new build and social housing projects. Available in outputs of 24kW, 28kW and 33kW, the Promax Combi is easy to install and can be fitted in the majority of domestic property sizes.

The Promax Combi is a fully modulating boiler, offering end users gas savings of up to 37% when installed with a Gas Saver flue gas heat recovery unit. With flueing options of up to 20m and built in frost protection, the Promax Combi is a versatile and reliable boiler which can be easily installed in a number of locations across small, medium and large-scale installation projects.

To register a Potterton Promax Combi, click here

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.

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  • 24kW, 28kW and 33kW - a model to suit most property sizes
  • Robust hydraulic connections - for quality and reliability
  • N0x Class 5 - best in class
  • Fully modulating and highly efficient - the Promax Combi intelligently uses the right amount of fuel to meet the set central heating temperature, saving the end user money on fuel bills
  • Pre-plumbing jig - saving time on installation 
  • Compatible with Multifit GasSaver
  • End users can see savings of up to 37% on gas for domestic hot water
  • Flueing options of up to 20m - offering flexibility for a variety of different housing projects
  • Optional stand-off bracket - allows pipes to be routed behind the boiler
  • Separate central heating and domestic hot water controls 

View product specification

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

Potterton Promax Combi 


Units  24  28  33 
Sales code 7219453 7219455 7219456


Concealed user controls    Yes  Yes   Yes  
Operating mode selector switch with reset    Yes   Yes   Yes  
User adjustable DHW temperature    Yes   Yes   Yes  
User adjustable CH temperature    Yes   Yes   Yes  
LED temp/status/fault diagnosis display    Yes   Yes   Yes  
Integral 24hr electro-mechanical timer    Optional Optional Optional
Integral 7 day electronic timer    Optional  Optional  Optional 
Single channel wireless programmable room thermostat  Optional  Optional  Optional 
Weather outdoor sensor    Optional  Optional  Optional 


Gas (natural gas/LPG) NG NG NG
Inlet supply pressure mbar 20  20  20 
Maximum gas rate  m3/hr  2.6  3.1  3.6 
Heat input central heating (CH)  kW Max Gross (QnHs)  22.7 27.4 32.1 
kW Min Gross (QnHs)  7.8  10  10.8 
Heat output CH non-condensing  kW Max (Pn)  20.6  24.7  28.9
kW min (Pn)  6.8 8.7  9.4 
Heat output CH condensing  kW max (Pnc)  21 25.9 30.3
kW min (Pnc)  7.4 9.5 10.2
Heat input domestic hot water  kW Max Gross (QnwHs)  27.4 32.1 37.7
Heat output domestic hot water  kW Max (Pn)  24 28  33
SAP 2009/2012 annual efficiency (PCDB/SEDBUK)  89.0 89.0  89.0 
NOx class   

ErP product information 

NOx  mg/kWh  20 23  20
Sound power level, indoors  LWA DB  50  53  52 
Space heating efficiency class   
Water heating declared load profile    XL  XL  XL 
Water heating efficiency class   
EcoHomes    3


Electrical supply  Volts/Hz  230/50  230/50  230/50 
Permanent live required  Yes  Yes  Yes 
Fitting electrical cable    Yes  Yes  Yes 
Power consumption  Watts  85  120  125
External fuse rating  Amps 
Internal fuse rating  Amps  F2L  F2L  F2L 
Ingress protection rating    IPX5D  IPX5D  IPX5D 
Integral 'boiler only' frost thermostat    Yes  Yes  Yes 


Pre-plumbing/wall mounting jig    Yes   Yes   Yes  
Isolating valves    Yes   Yes   Yes  
Gas supply connection  mm  22  22  22 
Central heating connections  mm  22  22  22 
Domestic hot water connections  mm  15  15  15 
Condensate drain connection  mm  21.5 21.5 21.5
Filling loop kit   Yes Yes     Yes


Domestic hot water output (raised 35°C) (max)  I/min  9.8  11.5 13.5
Domestic hot water operating flow rate (min)  I/min  2 2 2
Domestic hot water operating pressure (min)  bar  0.15  0.15  0.15 
Domestic hot water system pressure (max)  bar 
CH safety discharge pressure  bar 
Integral automatic bypass    Yes   Yes   Yes  
Integral expansion vessel capacity  litres 
Max capacity of central heating system  litres  125  125  125 
Compartment ventilation requirement    No  No  No 
CH system inhibitor required    Yes   Yes   Yes  
24 hour pump exercise   Yes   Yes   Yes  
Pump overrun    Yes   Yes   Yes  

Concentric flue systems 

Concentric flue diameters   60/100 and 80/125  
Standard horizontal flue kit length (ø60/100)  mm  685 685 685
Max equiv length horizontal/vertical (ø60/100)  10 10 10
Max equiv length horizontal/vertical (ø80/125)  20 20 20
Equivalent length per 135° bend  10 10 10
Equivalent length per 93° bend  20 20 20

Twin flue system 

Twin pipe flue Diameters  mm  80/80 80/80 80/80
Maximum equivalent vertical length 15 15 15
Maximum equivalent horizontal length m 15 15 15


Max installation lift weight  kg  40.2 40.2 40.2
Gross packaged boiler weight  kg  45.5 45.5 47
Packaged boiler dimensions (WxHxDxSCxUCxLCxFC)  450mm x 780mm x 345mm x 5mm x 175mm (300mm 80/125 flue) x 150mm x 5mm (450mm for servicing)

Promax Combi literature

Potterton Promax Range Guide updated 17/05/2017 (15.43MB) Tenants leaflet example updated 30/06/2017 (3.90MB) Promax combi user guide updated 05/01/2016 (1.53MB) Promax combi installation and servicing manual updated 08/03/2017 (5.86MB)

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

  • Integral 24 hr electro-mechanical timer
  • Integral 7 Day electronic
  • Single channel wireless programmable room thermostat
  • Potterton RF digital 7 day programmable roomset (wireless)
  • Multifit Outdoor Sensor Kit
  • Filling loop kit
  • Stand off kit (facilitates vertical pipe runs behind boiler)
  • Multifit gas saver (natural gas)
  • Multifit (gas saver) expansion vessel kit
  • Gas saver - stand off kit
  • 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)
  • Terminal guard ∅  60/100
  • Stainless steel PDK guard ∅  60/100 - air intake S/S

Promax Combi ErP labels

Promax combi ErP label updated 08/04/2016 (0.13MB) Product fiche Potterton Promax Combi updated 09/09/2015 (0.10MB)

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