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Mob: 07486 024405

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Webasto Boat Heating Systems

Webasto Boat Heating Systems

Webasto Marine Heating Systems - How to choose the product for your boat

Your choice of Webasto Marine heating system will depend on your boat heater outlet requirements and the size of your boat. Smaller boats or yachts will benefit from a simple, 1 or 2 outlet Webasto heater kit, possibly an Airtop 2000 which is relatively easy to install. Whilst larger craft may require more complex installations, with up to 4 or 5 outlets or possibly 2 small separate Air Top units, to allow hot air heating to all areas of the boat.

The first decision you will need to make, is how many rooms you need or want to heat. The size of the unit will be dictated by this. Often this ultimately depends on the size of your boat or Yacht. Great caution when making this initial decision is needed as heat from an inadequate output source will soon disperse, not allowing you to bring your boat to the desired optimum temperature. This basically causes your diesel heater to work twice as hard as it should, yet still not producing the temperature you may desire in your boat or yacht. As a guideline, for boats used in UK waters and used in all but extremes of climate, you can follow the information provided in the table below. Again further caution is needed as its much better to put in a heater that is too large than one that is undersize

Marine Heating Systems - Which size Air Top

Marine Heating Systems - Which size Air Top

Number of

Outlets

Heater Type Suggested Uses
1-2
AIR TOP 2000 (2kW)
Sailboat LOA <25', Motor boat LOA <28'
2-4

AIR TOP EVO

3900 (3.5kW)

Sailboat LOA 25'-34', Motorboat LOA 28'-36'
4-6

AIR TOP EVO

5500 (5kW)

Sailboat LOA 35'-45', Motorboat LOA 37'-46
Fly bridge motor cruisers may require larger heater units due to increased cabin volume and glass surface area


Choosing the right Webasto Diesel Heater

Please note that the Air Top "EVO" units have an "overburn" function which allows a greater heat output for short periods of time (3.9kW instead of 3.5kW, & 5.5kW instead of 5kW) as a heat "BOOST" function.

When choosing a Webasto Marine Heating kit it is important you take into consideration the outside climate that you will be operating the heater within, as well as your intended use. Will you use your Webasto Diesel heater to heat your cabin on an artic expedition? or are you simply taking the chill out of the night breeze while spending the summer in the Mediterranean.

Another important consideration is the length of the ducting that you will require. Even with the Webasto Thermo Installation, heat will inevitably be lost along extend lengths of ducting. If you require heat to be blown through a long length of ducting it may be advisable to choose a larger Webasto Air Top model.

Though it is ideal to have an outlet in every living space of your boat, it is seldom likely to be the easiest or most cost effective solution. Remember that with hot air heating systems, the air is rapidly dispersed if doors etc. are left open and heat can effectively be contained and channelled to necessary areas by use of your doors and hatchways

By now, you should have an idea of what Webasto Heater unit you will require and more than likely how many outlets and where they will be placed. This should enable you to choose the kit you require, though if you think your requirements are not met by any of the kits we offer, do not hesitate to e-mail us your considerations and allow us to advise of possible solutions for you.

To view our selection of Webasto Air Top & Air Top Evo kits, please click on the link

For our range of Webasto Thermo Water Heater kits please click here.

Webasto Diesel Heater Instalation Guide

As each boat and individuals requirements are different, so each installation is relatively unique. However, there are a few simple rules and guidelines which will help you in your selection and installation of a Webasto Marine Heating system.

The basic installation requires the heating unit to be fitted, usually near to the engine bay as it will require a 12V feed and access to the diesel system on the boat (unless a separate tank is fitted). The hot air produced by the unit is fed around the boat via special ducting (hose), you must work out where around your boat you would like the outlets to be. Then take into account the ease of access for routing the ducting through the boat.

Once you have decided on the location of your Websato Diesel Marine Heater, follow the installation instructions provided with the kit. You will need to mount it securely, take a feed off the diesel line and install a pump (which also acts as a non-return valve), have access to a 12V power supply and install a thru-hull exhaust. The control unit also plugs in to the boiler unit.

Once a Webasto Air Top heater has been installed, the ducting needs to be connected and fed through the boat to distribute the warm air. Specialist ducting is used to do this that minimises the heat, though if particularly long runs are being used we recommend using the Webasto Thermo Duct, to insulate and provide more efficient heat distribution.

The size of ducting you use will depend on the unit you have purchased:
  • Air Top 2000 has a 60mm outlet
  • Air Top EVO 3500 and EVO 5500 have a 90mm outlet.


  • Webasto Air Top 2000 installations will usually only ever provide 1 or 2 outlets, so it is simply a case of using a suitable splitter (Y-piece) to channel the ducting to the relevant outlets*

    On the larger units with a 90mm outlet from the unit, the simple rule is to have one main run of 90mm ducting, ending in an open* 90mm outlet in the main heated area. Along the length can be inserted the "90mm x 60mm x 90mm" Y-pieces which will spur off the heating to smaller 60mm ducting and provide heat to smaller close-able outlets.

  • For safety, all installations must have 1 open (non closable) outlet.


  • On larger yachts, or where routing around areas is difficult, it is normal to install 2 x Air Top Heaters to provide adequate heat to all areas of the boat.

    Outlets are generally of 2 types, close-able and open. Options are available for colours and other types, but we have offered the general and most used types in the on-line catalogue.

    Outlets & Vents

    Most are flush fitted through panels and use louvers to gently direct the hot air around the space as required. It is essential that each "spur" of the system terminates in a suitable outlet

    After installing the Boiler unit, connecting to the electrical and diesel supplies, and channelling the ducting around the boat, the last stage is to install the controller unit. This plugs into the boiler unit and is usually mounted in a reasonably accessible place, such as the saloon, or near the electric switch panels, or even in a cabin, depending on the layout of the boat and the length of cable.

    After installation, check all connections and fittings, and ensure all ducting is secure, before setting the required temperature on the control dial and testing the system. Though the air coming from the vents may at first have a little odour due to the newness of the system etc., no diesel fumes or engine smells should be apparent. If you suspect this, or any other elements of the system are not working correctly, switch the unit off and seek professional assistance.

    It sounds obvious, but read through the operation manual carefully. When used correctly the system will provide quiet, efficient heating to specific areas of the boat and even a "no heat" option to assist in ventilating the craft with fresh air.

    Air Top 2000 Spare Parts

    Common Replacement Parts For Air Top 2000ST

    Item No
    Description Parth No.
    1

    Inlet Hood (from serial no 976400)

    Inlet Hood

    1310012B

    67490D

    2

    Outlet Hood 60mm diameter

    Outlet Hood 75mm diameter

    67491D

    98503B

    3
    Control Unit Cover 29718B
    4
    Upper Plastic Casing 9019555A

    5

    6

    power Plastic Casing

    Grille

    67488F

    67492A

    7

    Control Unit 12v Diesel

    Control Unit 24v Diesel

    9013146A

    9013147A

    8
    Combustion Air Fan 1302774B
    9

    Drive Assembly 12v (with dosing pump cable from serial no 976400)

    Drive Assembly 12v (with long dosing pump cable from serial no 976400)

    Drive Assembly 24v (with dosing pump cable from serial no 976400)

    Drive Assembly 12v (with dosing pump cable)

    Drive Assembly 12v (with long dosing pump cable)

    Drive Assembly 24v (with dosing pump cable)

    1302786A

    1302787B

    1302788A

    1303846A

    1303847A

    1303848A

    10
    Gasket Set 1303517A
    12
    Burner Insert Diesel 1302799A
    13

    Glowpin 12v

    Glowpin 24v

    9005086A

    9005087A

    14
    Burner Tube 82284A
    15
    Isolator 1303326A
    16
    Heat Exchanger Diesel 1302805A
    17
    Overheat Sensor 9005084A
    Not Shown

    Fuel Pump 12v Diesel

    Fuel Pump 24v Diesel

    82553B

    47901B

    Not Shown Basic Wiring Harness 9003696G
    Not Shown

    Air Top 2000 ST 12v Service Kit (contains Burner with glowpin & gasket set)

    Air Top 2000 ST 24v Service Kit (contains Burner with glowpin & gasket set)

    4111814A

    4111815A

    Air Top 3000/5000 Spares

    Air Top 3000/5000 Spares

    Common Replacement Parts For Air Top Evo 3000/5000

    Item No
    Description
    Part No.
    1
    Top CasingAir Top Evo 3900/5500 98649B
    2
    Bottom CasingAir Top Evo 3900/550098648B
    3
    Air Inlet HoodAir Top Evo 3900/550098650B
    4
    Air Outlet HoodAir Top Evo 3900/550098651B
    5
    Electronic Control Unit 12v Air Top Evo 3900 Diesel

    Electronic Control Unit 24v Air Top Evo 3900 Diesel

    Electronic Control Unit 12v Air Top Evo 5500 Diesel Standard Version

    Electronic Control Unit 24vAir Top Evo 5500 Diesel Standard Version

    Other specialist version control units are available, dependent upon the model Airtop Evo versionplease refer to Webasto spare parts list pricing available upon request

    9019488A

    9019486A

    1313133A

    1313136A

    6
    Overheat Temperature SensorAir Top Evo 3900/55001313158A
    7
    Replacement Isolator SetAir Top Evo 3900/55001303326A
    8
    Drive Assembly 12v/24v Air Top Evo 3900

    Drive Assembly 12v/24v Air Top Evo 5500

    9018417A

    1313121A
    9
    Glowpin 12v Air Top Evo 3900/5500

    Glowpin 24v Air Top Evo 3900/5500

    1314150A

    1314151A

    11
    Burner Cartridge Diesel Air Top Evo 3900/55001313132A
    12
    Burner Tube Air Top Evo 3900/55009006653A
    13
    Gasket Set Air Top Evo 3900/550091364A
    14
    Heat Exchanger Air Top Evo 3900/55001314152A
    15
    Screw SetAir Top Evo 3900/55009004229A
    Not ShownFuel Pump 12v Diesel

    Fuel Pump 24v Diesel

    82553B

    47901B

    Not ShownUniversal Wiring Harness Marine 10m Lg1313123B
    Not ShownReflector Foil (Pack of 5 pieces)9022102A
    Not ShownAir Top Evo 3900 / 5500 12v Service Kit (contains Burner with glowpin & gasket set)

    Air Top Evo 3900 / 5500 24v Service Kit (contains Burner with glowpin & gasket set)

    4111823A

    4111824A

    Exhaust Spares Air top 2000

    Exhaust Spares Air top 2000

    Combustion Air & Exhaust For Air Top

    Item No
    Description Part No.
    1
    Air Intake Silencer Pipe 22mm 492345
    2
    Combustion Air Hose 22mm 4158308
    3
    Combustion Air Hose End Cap 24048A
    4
    Hose Clip 20-27mm 1303080A
    5
    P Clip 25mm 405256
    6
    Exhaust Silencer 22mm 86450C
    7
    Exhaust 22mm (S/Steel per m)337390
    8
    Exhaust End Cap318302
    9
    Exhaust Clamp 22mm20965A
    10
    P Clip 25mm405256
    11
    Hose Clamp 26-28mm91383B
    12
    Exhaust Elbow 22mm28472C
    13
    Exhaust Pipe Adaptor 22-24mm92641A
    14
    Exhaust Silencer (Leakproof)9014067A
    Not ShownSilicone Exhaust Grommet 22mm4132900
    Not ShownExhaust Lagging 30mm (per m)41V0001
    Not ShownS/Steel Cable Ties (for exhaust lagging)4162441
    Not Shown

    Exhaust Skin Fitting 24mm(Straight)

    Exhaust Skin Fitting 24mm (90?)

    9018377A

    9018379A

    Exhaust Spares Air Top Evo3000/5000

    Exhaust Spares Air Top Evo3000/5000

    Combustion Air & Exhaust for Air Top 5500

    Item No
    Description
    Part No.
    1
    Air Intake Silencer Pipe90416D
    2
    Combustion Air Elbow91563A
    3
    Combustion Air Hose assy inc cap90416D
    4
    Combustion Air Hose End Cap29517A
    5
    Exhaust Silencer90378C
    6
    Exhaust Elbow91564B
    7
    Exhaust End Cap4143034
    8
    Exhaust Silencer (leakproof)9014067A
    9
    Exhaust Clamp91383B
    10
    Exhaust 24mm (S/Steel per m)90394A
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