Our website uses cookies to help provide you with the best experience tailored to your interests. To use the website with full comfort, please accept to receive all cookies on our website. For more information with regard to Cookies please see our Privacy policy.

Accept Decline

Ultimate₃ regular boiler

Exclusive regular boiler with 5 years guarantee*

  • ErP A rated for efficiency - to reduce energy bills
  • £15 reward when registered through Club Energy
  • Lightweight boiler with cupboard fit dimensions
  • FREE 5 Year guarantee when registered on Club Energy*

The Ultimate3 regular (open vent) boiler is suitable for homes with high hot water demands. The Ultimate3 regular heat only boiler is available in a 25kW output and has been designed to be light and compact with cupboard fit dimensions. The boiler features flexible flue options and an aluminium heat exchanger for proven reliability and performance.

Features & benefits

  • Modern bright LCD display - Excellent clarity of boiler information, making it easy to change and confirm settings in dimly lit areas.
  • High efficiency - ErP 94% A rated boiler that helps reduce energy bills.
  • FREE 5 year guarantee* - Parts and labour guarantee for 5 years when registered through Club Energy.*
  • Heat exchanger - Made with high grade aluminium for proven and reliable performance.
  • Exclusive to City Plumbing Supplies and Plumbing Trade Supplies



Ultimate₃ Regular boilerUnit25kW
Article number 0010021408
Gas Council number 47-019-52
Casing dimensions (H x W x D)mm600 x 375 x 280
Nominal heat output range at 50/30˚C
(Condensing mode)
kW6.4 - 26.5
Nominal heat output range at 80/60˚C
(Non condensing mode)
kW6 - 25.2
Domestic Hot Water
Lowest water pressure to operate boilerbar0.2
Heat exchanger material Aluminium
Boiler lift weight (Dry boiler)kg22
ErP efficiency%94
ErP decibel rating (sound power)dBa51
PCDB seasonal efficiency%89.6
Flueing options
Maximum horizontal flue length 60/100m10
Maximum vertical flue length 60/100m10

For full specification, please download here (2878 kB).

Related Products

Related Products

Climapro₂ RF Control

  • Two channel wireless programmable room thermostat
  • Backlit display provides advanced user control and functionality
  • Capable of room and weather compensation*

Introducing MiGo

  • Wi-Fi thermostat and easy-to-use app
  • Manage heating and hot water from anywhere
  • Reduces energy consumption, saves money

Climastat room thermostat

  • Easy to use
  • Extra low voltage
  • Simple & discreet 2 wire connection

Climapro₁ control

  • Annual service reminder function
  • Automatic update for summer and winter
  • Simple and discreet



Alternative products

Alternative products

Ultimate₃ combi boiler

  • Leading combi boiler offering great performance
  • FREE 10 year guarantee when registered on Club Energy*
  • £15 reward when registered through Club Energy
  • Available in 30kW and 35kW models

Ultimate₃ system boiler

  • ErP A rated for efficiency - helping to reduce energy bills
  • FREE 5 year guarantee when registered on Club Energy*
  • £15 reward when registered through Club Energy
  • Available as 25kW model