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ecoFIT pure open vent boiler

412, 415, 418, 425, 430 and 435 outputs

  • Compact, cupboard fit solution
  • Top and rear flue options
  • Automotive grade aluminium heat exchanger
  • Easy installation and maintenance
  • Standard 2 year warranty. Free 7 year warranty when registered by a Vaillant Advance partner (promotion until 31/12/18)


Introducing the boiler that opens more doors: the new ecoFIT pure

As one of Europe’s leading heating technology manufacturers, ‘thinking ahead’ is a culture which is embraced throughout Vaillant. Our products feature high energy efficiency ratings and low emissions, and come with an enviable reputation for performance, quality and reliability. This comes from proven German engineering combined with award winning UK manufacturing.

Ultra-quiet operation (Quiet Mark approved), small footprint and total flexibility of siting (with top and rear flue options) mean that the ecoFIT pure range fits in with your customers’ needs.The automatic purging assistance and high specification, aluminium heat exchanger makes for a lightweight installation. High quality and high efficiency, together with the complete availability of spare parts and the easy accessibility of the unit layout mean the ecoFIT pure is easy to maintain too.

Features & benefits:

  • Available in 12, 15, 18, 25, 30 and 35kW outputs
  • Top and rear flue options on all boiler models - Allows flexible siting options and installs in various property types
  • Compact, cupboard fit solution - Small boiler footprint, offering flexibility of siting, including a cupboard-fit
  • Clear LED display - Offers visibility in dimly lit areas for easier installation and use
  • Easy installation and maintenance - Accessible layout that allows all components to be replaced from the boiler front
  • Recognisable Vaillant fault codes - Making it easy to diagnose faults
  • High specification aluminium heat exchanger - Designed to last longer, maintain easily, and reduce energy bills
  • High quality components - Offering peace of mind for the lifetime of the product
  • Industry leading flue lengths - 10m flue length across all ecoFIT pure boiler outputs
  • 4-sided cooling and water agitation of the heat exchanger - Reducing stress on the heat exchanger for longer life reliability and reduced maintenance costs
  • Compatible with Vaillant’s intelligent range of controls - For the most convenient and energy efficient system, saving on energy bills
  • Standard 2 year warranty, can be upgraded to a free 7 year warranty when registered through Vaillant Advance. For homeowner piece of mind
  • Option to purchase extended warranty up to 10 years when registered through Vaillant Advance



Technical dataUnit of measureecoFIT pure 412ecoFIT pure 415ecoFIT pure 418ecoFIT pure 425ecoFIT pure 430ecoFIT pure 435
Boiler type open ventopen ventopen ventopen ventopen ventopen vent
Signature model output 12kW15kW18kW25kW30kW35kW
Article number 001002040000100204010010020402001002040300100204040010020405
Gas Council number 41-694-0841-694-0941-694-1041-694-1141-694-1241-694-19
Boiler dimensions (HxWxD)mm602 x 375 x 295602 x 375 x 295602 x 375 x 295602 x 375 x 295602 x 375 x 295602 x 375 x 295
Nominal heat output range at 50/30˚C (Condensing mode)kW4.7 - 12.84.7 - 15.95.2 - 19.16.4 - 26.57.4 - 31.87 - 35.8
Nominal heat output range at 80/60˚C (Non condensing mode)kW4.5 - 12.34.5 - 15.25 - 18.3 6.1 - 25.47.1 - 30.57.2 - 34.8
Maximum flow temperature°C808080808080
Flow temperature range°C10 - 8010 - 8010 - 8010 - 8010 - 8010 - 80
Flow temperature factory setting°C757575757575
Approximate condensate volume at 50/30°Clitres/hr1.231.531.842.553.063.65
Modulation (max/min)1 : X1:3.31:41:51:4.91:4.91:4.9
Domestic Hot Water
Maximum heat output for water generationkW151825.2303535
Lowest water pressure to operate boilerbar0.
Lowest water flow for operationl/min------
Lowest water pressure for maximum flow ratebar------
Domestic hot water flow rate (at DT = Δ35K) *l/min------
Hot water output temperature range˚C------
Expansion vessel sizelitres------
Gas inlet connection (pipe size)mm151515151515
Heating flow and return connections (pipe size)mm222222222222
Hot and cold water connections (pipe size)mm151515151515
Heat exchanger materialStainless/AluminiumAluminiumAluminiumAluminiumAluminiumAluminiumAluminium
Boiler lift weight (Dry boiler)kg222222222222
NOx class 555555
NOx (En 15502-2-1)mg/kWh323339394032
ErP efficiency%949494949494
ErP decibel rating (sound power)dBa454851525555
Fluing options
Maximum horizontal flue length 60/100m101010101010
Maximum vertical flue length 60/100m101010101010
Maximum horizontal flue length 80/125m252525252525
Maximum vertical length 80/125m252525252525
Rear flue optionsYES/NOYesYesYesYesYesYes

*flow restrictor fitted to achieve a Δ42K rise

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