Webasto pre heater

Anyone know what KW output the d3/4 webasto pre heaters are? Thinking of fitting one to central heating in static caravan, need a min of 5kw really.
Tia

Jamiegreen said:

Anyone know what KW output the d3/4 webasto pre heaters are? Thinking of fitting one to central heating in static caravan, need a min of 5kw really.
Tia

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I reckon you are talking 3 to 4 kilowatts . I have the thermotop pro 90 fitted on my landy and at full chat it's 9 kilowatts I believe

Here's from the D3 WSM FBH description:
"The FFBH is controlled at one of two heat output levels, 2.8 kW at part load combustion and 5 kW at full load
combustion."

Thats good to hear.. so its a fairly standard webasto, some wire joining and a fairly basic thermostat and should be up to the job. Works out as one cheap boiler when they go for $40-$100

I've also read they build up carbon deposits a lot faster at lower output, so maybe better to just have the thermostat toggle it either full on or off untill required again.

The webasto pre-heaters have a built in timer as to not function more than 30 minutes after a start-up then they need time to ''rest" otherwise theyr's life span will be reduced also theyr's current draw is not neglectable, the battery would not last for too long ... i doubt that's a good choice to keep prolonged constant heat in a caravan

On the D3 in winter, it is not unusual to drive 100 miles and when you get to your destination, the fbh is still running.

I am not sure where people are getting the 30 min max run time from? lots of people use them on boats etc
Guy I know has run one for years, and just recently replaced it as the ecu died.

D3 ones will need a CAN signal to start, the webasto oval timer provides that signal, I bet if you trawl the canal boat forums you will find all the info you need.
The early ones just need 12 volts signal to start, later ones not only need a CAN signal some require different types on CAN signal, V CAN, W CAN etc, have a google, do not ask me, as I have no idea!

Lots of other makes of cars also run the same Webasto heaters, but again it is the signal that starts them that you need to know.

lynall said:

On the D3 in winter, it is not unusual to drive 100 miles and when you get to your destination, the fbh is still running.

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Then IMO there is a problem with the cooling system cos webasto auxiliary heater is made as to stop when the coolant temp gets to 76*C so if i still works the coolan temp is below that

lynall said:

I am not sure where people are getting the 30 min max run time from? lots of people use them on boats etc

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that's how mine does, retrofitted thermo top c with oval timer fitted by webasto lincensed personnel and that's how it's set by them, i asked them why the 30 mins as i was curious at that time and they said that it's the best for the unit to last long ... AFAIK there is a difference between those made for vehicle auxiliary heater and those for caravans/boats etc... what i meant was to no use for caravan one which was dedicated for car auxiliary heater cos these are dependant on the vehicles ECT input.... there are special kits for caravans/boats with own analog water temp sensor

I know you can buy then more specifically designed for boats etc, which I was going to get a refurb one which go for about £300. But then I checked used car ones out of curiousity to see they go for as cheap as £40 and a bit more for later models. I figure with the correct wiring it's still a fairly standard webasto underneath, just giving it a signal from a room thermostat instead of a engine temperature. I was under the impression they all had a basic setup where feeding a certain wire a live signal kicks it on. Not sure about them requiring CAN signals, atleast on the around year 2010 models. Will try and find some wiring diagram.. worst case it's a little money wasted, and I'm not looking for any fancy setup, was just a thought.

Reading into it so far.. a Webasto Oval timer is deffo needed to give the right CAN signal to the LR webastos..

thats an interesting watch

i attach you the official docs i have

Thanks, so it seems the only non can-bus is the thermotop C. Little bit harder to find from any car manufacturer. On another note would I be right in saying the Discovery 2 factory webasto is a type C as correct me if im wrong the d2 does not use canbus.

I confirm that the retrofitted TTC on the D2 does not use CAN, it's managed only by the oval controller also AFAIK it was not factory fitted to anything cos it was sold as retrofit unit i dont know exactly what modell was factory fitted to D2 but it is similar with the TTC with a different software, IIRC on D3 was TTV... for any guides you have links here https://www.butlertechnik.com/technical_library/webasto-manuals-d3

sierrafery said:

Then IMO there is a problem with the cooling system cos webasto auxiliary heater is made as to stop when the coolant temp gets to 76*C so if i still works the coolan temp is below that
that's how mine does, retrofitted thermo top c with oval timer fitted by webasto lincensed personnel and that's how it's set by them, i asked them why the 30 mins as i was curious at that time and they said that it's the best for the unit to last long ... AFAIK there is a difference between those made for vehicle auxiliary heater and those for caravans/boats etc... what i meant was to no use for caravan one which was dedicated for car auxiliary heater cos these are dependant on the vehicles ECT input.... there are special kits for caravans/boats with own analog water temp sensor

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Apparently the fbh still running after a long journey during winter is quite common, maybe as the vehicle slows down, and comes off load so running light, the temp drops and the fbh starts again?

IMO on a modern vehicle like the D3 if the thermostat and cooling fan works well once it went up to working temp(aroud 90*C) it should not fluctuate much with engine running... when the engine comes out of load so does the cooling fan.

sierrafery said:

IMO on a modern vehicle like the D3 if the thermostat and cooling fan works well once it went up to working temp(aroud 90*C) it should not fluctuate much with engine running... when the engine comes out of load so does the cooling fan.

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Stat is a genuine new one about 2 yrs ago, and viscous only runs from a cold start, never heard it run in anger yet

I have friends here with D3s some wih FBH others without and all i know is that once the engine is up to normal temp it stays there even at -10*C on those without FBH too so i dont see the reason why the FBH would work then

If my d2 can hold temp with heaters on in minus conditions I would have thought a d3 would have no problem. Not to say I wont be fitting one though because she takes her time getting there.

Also found this which hopefully it’s not a duplicate of what information has already been linked to