webasto 3500 Airtop Diesel Heater

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cygnusv

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12 Feb 2013
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287
Location
Yorkshire, UK
www.best-camping-stoves.com
Does anyone know if the main circulating air fan is capable of being serviced. It's showing a fault of F08. I believe it's possible that the brushes in the motor are worn causing motor speed to vary, in turn triggering a fault and the heater to shut down.
Replacement costs for a new fan motor is in the region of £400.
Any ideas?
Many thanks
 
cygnusv said:
Does anyone know if the main circulating air fan is capable of being serviced. It's showing a fault of F08. I believe it's possible that the brushes in the motor are worn causing motor speed to vary, in turn triggering a fault and the heater to shut down.
Replacement costs for a new fan motor is in the region of £400.
Any ideas?
Many thanks
Click to expand...

I've no personal experience, but from recent posts on here, it seems that for your £400 you could buy three complete equivalent (Chinese) heaters. :D
 
My experience of Chinese goods has been very poor. They make stuff that looks great, but awful quality.
In saying that the Webasto and Eber marques are ridiculously overpriced. Maybe the possible threat from China, will wake them up and force them to be more competitive.
 
Yes you can repair the fan motor. One of my retirement hobbies is fixing Eberspachers ( yes, sad I know!!).
I very rarely have to actually repair a fan as I just cannibalise parts, but I have had their motors in bits and it is quite possible to repair them.
I never did buy the new bearings or brushes but other forumites have done this and will hopefully appear!
The two makes are very similar so with a bit of guidance I am sure you will manage.
 
First test is to power the motor up (with it removed from the case) from a regulated power supply to see exactly what the motor does. If it waves about the place at different speed then it could be worn bits inside. If it doesn't vary in speed, it could been drag on the casing. Sometimes it makes a noise and sometimes it oddly doesn't.

Check for any marks on the casing also.

They can be repaired as a DIY economically, but not usually professionally.

How old is the heater?
 
Thanks for your helpful comment. I'm very pleased to hear that a repair is feasible. I don't know how old the unit is but maybe the following numbers might help.
Ident' number 92049C
Fabrique num' 3B050589
Any tips on how to remove the fan without damage?
Many thanks
 
You need to get the manual. There a couple of sites which you can access that other forumites will have the names of Le tonkinitis ( or similar and a UK heater supplier)

On Ebers I remove the whole fan assembly then pull the fan blades of the spindle , then carefully lever off the inner 'fan' You should then see the screws which will allow the motor to be removed. Dissembling the motor will allow you to identify the worn parts.

Best to check as advised above that there is nothing simple like catching fan blades and then apply volts directly to the fan
(Check the input voltage on the motor first, it may be only 9 volts ) reducing the volts should cause the fan to slow down. There may be info about the desired rpm at different volts in the manual.
 
It may be difficult to buy these under a webasto heading. I would remove them and size them up and troll the net for the same size. There should be a manufactures part no or ID on the motor which may help locate them.
Once you have sourced and fitted them and got it all working you then write up your efforts ( with some pics!), list the parts you got and from where then post it on here titled 'DIY repairs to Webasto fan motor' or similar!
Quite possibly someone on here has done this and will respond!
 
cygnusv said:
That's really helpful, thankyou. Where would I get replacement brushes?
Click to expand...

If it's just the brushes then you can probably cut/file some other brushes to size?
Out At5000 (pretty similar) failed in 2018. Fan problem. It turned out to be simply mechanical. There are thrust washers to hold the shaft in position. One collapsed/wore out, causing a motor stall. The brushes heated up - melting their plastic guides. Making it impossible to repair. Got a replacement fan assy from the Czech republic for less than anywhere west of that. If the motor had been built with old style materials it might not have cratered, but thermo-plastic brush guides do not cut the mustard. It is running again- re-incarnated as a garage space heater. The boat now has a brush-less Planar heater! Repairing the Webasto would have cost me more than the entire Planar, had I not replaced 2 MOSFET switches myself.
 
I wanted to change the windings from 24V to 12 Volts on a Webasto 3500 and gave up. Would not take this fan apart, because of the close tolerances.
 
It is possible just you have to make sure everything goes back really really clean and is put together square.

OP - have you tried powering it up away from the heater as yet? Had one this morning on a service call with about 100 miles of cobweb wound up inside it and sounded very weird and was speeding up and slowing down. Made me think of you lol

Frankklose said:
I wanted to change the windings from 24V to 12 Volts on a Webasto 3500 and gave up. Would not take this fan apart, because of the close tolerances.
Click to expand...
 
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