Potterton Promax Ultra

The Potterton Promax Ultra Combi has been designed specifically for social housing and new build projects.

Contact your BDM
Suitable for

Social Housing

New Builds

Single boiler output
24kW, 28kW, 33kW and 40kW

40kW model available
Delivering a higher domestic flow rate for larger properties

Flueing options
Up to 20 metres

Available in outputs of 24kW, 28kW, 33kW and 40kW, the Potterton Promax Ultra Combi delivers domestic hot water flow rate up to 16.4 litres/minute and has  an excellent SAP 2012 seasonal efficiency rating for cost effective compliance with the Building Regulations.

The Promax Ultra comes with built-in frost protection and flueing options up to 20 metres so it can be installed almost anywhere, offering greater siting flexibility.

To register a Potterton Promax Ultra boiler online, click here

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
  • 24kW, 28kW, 33kW and 40kW models available - a model to suit most sizes of property
  • 40kW model - delivers a higher domestic hot water flow rate for larger properties
  • SAP 2012 seasonal efficiency figure  - for cost effective building regulations compliance
  • N0x Class 5 - best in class
  • Flueing options of up to 20m - offering flexibility for a variety of different housing projects.
  • One boiler to suit both fuel types -  no conversion kit required
  • Pre-plumbing jig -  saving time on installation.

View product specification

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

Potterton Promax Ultra Combi 


Units  24  28  33  40 
Sales code 7223762  7223763  7223764  7223765 


Concealed user controls    Yes  Yes   Yes   Yes  
On/off switch with reset    Yes   Yes   Yes   Yes  
User adjustable DHW temperature    Yes   Yes   Yes   Yes  
User adjustable CH temperature    Yes   Yes   Yes   Yes  
LED temp/status/fault diagnosis display    Yes   Yes   Yes   Yes  
Integral 24hr electro-mechanical timer    No  No  No  No 


Natural gas  mbar  Yes  Yes  Yes  Yes 
Nominal inlet supply pressure m3/h  20  20  20  20 
Maximum gas rate    2.61  3.05  3.59  4.35 
Propane LPG  mbar  Yes   Yes   Yes   Yes  
Nominal inlet supply pressure  kg/h  20  20  20  20 
Maximum gas rate  kg/h  1.69  2.29  2.70  3.27 
Heat input central heating (CH)  kW Max Gross (QnHs)  22.20  26.64  31.08  35.52 
kW Min Gross (QnHs)  3.89  4.32  5.33  6.55 
Heat output CH non-condensing  kW Max (Pn)  20.00  24.00  28.00  32.00 
kW min (Pn)  3.40  3.80  4.70  5.70 
Heat output CH condensing  kW max (Pnc)  21.20  25.30  29.60  33.80 
kW min (Pnc)  3.70  4.10  5.10  6.20 
Heat input domestic hot water  kW Max Gross (QnwHs)  27.40  32.10  37.80  45.80 
Heat output domestic hot water  kW Max (Pn)  24.00  28.00  33.00  40.00 
Maximum domestic hot water flow rate  I/min @ 35°C rise  9.8  11.5  13.5  16.4 
SAP 2009/2012 annual efficiency (PCDB/SEDBUK)  89.1  89.1  89.1  89.1 
NOx class   

ErP product information 

NOx  mg/kWh  15 17  15  24 
Space heating efficiency class   
Water heating declared load profile    XL  XL  XXL  XXL 
Water heating efficiency class   
EcoHomes    3


Electrical supply  Volts/Hz  230/50  230/50  230/50  230/50 
Permanent live required  Yes  Yes  Yes  Yes 
Fitting electrical cable    Yes  Yes  Yes  Yes 
Power consumption  Watts  85  90  90  100 
External fuse rating  Amps 
Internal fuse rating  Amps  F2L  F2L  F2L  F2L 
Ingress protection rating    IPX5D  IPX5D  IPX5D  IPX5D 
Integral 'boiler only' frost thermostat    Yes  Yes  Yes  Yes 


Pre-plumbing/wall mounting jig    Yes   Yes   Yes   Yes  
Isolating valves    Yes   Yes   Yes   Yes  
Gas supply connection  mm  22  22  22  22 
Central heating connections  mm  22  22  22  22 
Domestic hot water connections  mm  15  15  15  15 
Condensate drain connection  mm  21.50  21.50  21.50  21.50 
Safety discharge connection  mm  15  15  15  15 
Temporary filling loop included    Yes   Yes   Yes   Yes  


Domestic hot water output (raised 35°C) (max)  I/min  9.80  11.50  13.50  16.40 
Domestic hot water operating flow rate (min)  I/min  2.00  2.00  2.00 2.00
Domestic hot water operating pressure (min)  bar  0.15  0.15  0.15  0.15 
Domestic hot water system pressure (max)  bar 
CH safety discharge pressure  bar 
Integral automatic bypass    Yes   Yes   Yes   Yes  
Integral expansion vessel capacity  litres 
Max capacity of central heating system  litres  125  125  125  125 
Compartment ventilation requirement    No  No  No  No
CH system inhibitor required    Yes   Yes   Yes   Yes  
24 hour pump exercise   Yes   Yes   Yes   Yes  
Pump overrun    Yes   Yes   Yes   Yes  

Concentric flue systems 

 Concentric flue diameters   60/100 and 80/125  
Standard horizontal flue kit length (60/100mm)  mm  685 685 685 685
Max equiv length horizontal/vertical (60/100mm)  10 10 10 10
Max equiv length horizontal/vertical (80/125mm)  20 20 20 20
Equivalent length per 135° bend  0.50 0.50 0.50 0.50
Equivalent length per 93° bend  1.00 1.00 1.00 1.00

Twin flue system 

Diameters  mm  80/80 80/80 80/80 80/80
Max equiv length horizontal/vertical (parallel pipes)  15 15 15 15
Equivalent length per 135° bend  0.25 0.25 0.25 0.25
Equivalent length per 91.5° Bend  m 0.50 0.50 0.50 0.50


Max installation lift weight  kg  36.0 36.0 38.0 39.0
Gross packaged boiler weight  kg  41.5 41.5 43.5 44.5
Boiler dimensions (WxHxD)   450mm x 763mm x 355mm

Promax Ultra literature

Potterton Promax Range Guide updated 17/05/2017 (15.43MB) Tenants leaflet example updated 30/06/2017 (3.90MB) Potterton Ultra user guide updated 27/06/2016 (0.80MB) Potterton Ultra installation guide updated 27/07/2017 (16.83MB)

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

  • Programmable 7 day wireless sensor (2 channel)
  • Programmable 24hr wireless sensor (single channel)
  • 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 Ultra ErP labels

Product fiche Promax Ultra updated 21/09/2015 (0.10MB) Potterton Ultra ErP label updated 08/04/2016 (0.15MB)

Interested in this product for your premises? Complete the form below and someone from the team will contact you shortly.

Alternatively, speak to your Business Development Manager about this or any of our products.

Support from Potterton

Totally dependable.