Baxi 400 Heat

Baxi 400 Heat Only Boiler

Heat Only Boilers

Baxi 400 Heat

The Baxi 400 Heat has no need for a pump overrun or permanent live to save time during installation. This boiler can be installed on open vent or sealed systems and has an optional in-case rear flue for a neater installation.

Features and Benefits

Multiple outputs

Available in outputs of 15, 18 and 24kW 


Only 17.4kg installer lift weight


Easy-fit wall mounting bracket featuring a positive fix and audible lock, so you know it’s secure

Easy installation

1-metre lead included, allowing easy installation and removes the need to access the control box


Top central or optional in-case rear flue giving flexibility to site
Show More
Show Less

Product Literature

Installation and Service Manuals

Installation and Service Manuals

User Guides

User Guides

Specification Guides

Specification Guides

Product Documentation

No documentation available.

Product Fiche

Product Fiche

Product Documentation

No documentation available.

Energy Labels

Energy Labels

Baxi Heat Only Boiler Dimensions


A: Boiler Width = 370mm

B: Boiler Height = 625mm

C: Boiler Depth = 270mm

D: Side Clearance = 5mm

E: Upper Clearance = 190mm

F: Lower Clearance = 120mm

G: Front Clearance = 5mm in operation (500mm for servicing)

Technical Specification

Product Model




Product Code766893376689347668935
Operating mode selector switch with reset (Yes/No)YesYesYes
User adjustable CH temperature -Range - e.g. 30ºC to 80ºC (+/- 5ºC)YesYesYes
LED status/fault diagnosis display (Yes/nNo)YesYesYes
SAP 2009 Annual Efficiency (PCDB/SEDBUK) %
NOx class (1-5)555
ErP Product Information
NOx (mg/kWh)202123
Sound Power Level, Indoors (LWA dB)333435
Space Heating Efficiency ClassAAA
Heat Input CH -kW max gross (QnHs)18.3221.7528.62
Heat Input CH - kW min gross (QnHs)8.598.598.59
Heat Output CH (non condensing) - kW max (Pn)161925
Heat Output CH (non condensing) - kW min (Pn)
Gas supply pipe size (mm)222222
Inlet supply pressure (natural gas) - mbar202020
Maximum gas rate (m3/hr)1.752.072.73
Mechanical and hydraulic
Compartment ventilation requiredNoNoNo
Flow / return pipe size (mm)222222
Condensate discharge pipe (mm)21.5021.5021.50
Electrical supply - Volts/Hz230V/50Hz230V/50Hz230V/ 50Hz
Permanent live required (Yes/No)NoNoNo
Switched live (Yes/No)YesYesYes
Electrical power cable fitted as standard (1m of 3 core)YesYesYes
Power consumption (Watts)202333
External fuse rating (Amps)333
Internal fuse rating1.6T1.6T1.6T
Boiler IP rating (electrical protection) -Approval categoryIPX4DIPX4DIPX4D
Pump overrun (Yes/No)NoNoNo
Concentric flue system
Standard telescopic concentric flue (Length in mm)315-500315-500315-500
Standard in-case rear telescopic concentric flue (Length in mm)220-345220-345220-345
Horizontal concentric (60/100mm) - Max equivalent length (m)666
Horizontal concentric (60/100mm) - Reduction per 135º bend (m)
Horizontal concentric (60/100mm) - Reduction per 93º bend (m)111
Horizontal concentric (80/125 mm) - Max equivalent length (m)121212
Horizontal concentric (80/125 mm) - Reduction per 93º bend (m)111
Installer lift weight -Max (kg)17.417.417.4
Gross packaged boiler weight (kg)21.521.521.5

Contact your ASM

If you are a merchant or installer, your local Baxi representative is here to help.

More Information

Baxi combi Boiler - deconstructed

Baxi Genuine Parts

Whether you are working on an installation, repair or service, Baxi Genuine Parts are guaranteed for quality, reliability and safety. Start here to find the parts you need.
Baxi Boiler Training - Open Boiler 3

Product Training

Our training courses are held in our state-of-the-art training centres, several with CIPHE approval, by experienced, qualified engineers who know what the job is like.
Baxi Boiler Training Controls

Error Codes for Baxi Boilers

If a boiler develops a problem, it will display an error code. We explain the most common error codes here.  
Baxi Works App

Baxi Works

Baxi Works is our installer loyalty scheme, designed to prioritise you,support you and reward you for choosing Baxi.