Webasto problems - Where should I start looking

[Wunja]

Hi,
I have an elderly Webasto diesel heater which is not firing up, so I'm hoping one of the resident forum experts could point me in the right direction.
When I turn it on, and put the thermostat to full there is a loud click that comes at regular intervals (which I assume is the fuel pump). Then when I turn the heater off the fan cuts in, presumably for an un-necessary cool down period.
Are there servicable bits inside?
Please can you suggest a list of things to check?

Many thanks,

 

[narooma]

Do you need the instruction manual or have you got one?

 

[smeaks]

The click does sound like the fuel pump. After about 30 secs the fan should start once the fuel is away. The flame detector will shut down if no flame kicks in, that is when the fan runs on for two mins. The glow plug id usually the first suspect and can be changed easily enough if you have access to the unit.

good luck

 

[johnphilip]

Try first with the engine running, all these heaters need a really good battery capacity during their start up sequence, batteries that have been not charged during the winter might well be the problem. Heaters are amp eaters!

 

[sailorman]

Also check for a blocked filter if the pump is ticking but heater not starting

 

[Anthony]

clicking is not necessarily the pump, there is a relay in the control box that clicks on and off. if you touch the fuel pump you should be able to feel it pulse.

Also agree re engine running and check voltage levels etc.

Anthony

 

[FlorealIII]

first thing to do is dismantle it and clean the inside of the heater , and do not forget to clean the glowplug also .
cleaning can be done with gasoline or ordinary thinner .
I do this every two years

 

[FullCircle]

Vince, look at the control switch.
It should have alittle LED in the middle.
If there is a fault this should flash on and off.
Count the flashes and refer the manual.
Here are the codes

If the heater is equipped with a combination or standard
digital timer, a fault code is indicated on the display of the
digital timer whenever a malfunction has occurred:
F 00 Control unit failure / incorrect parameter set /
warm start detection
F 01 No start-up (after 2 start-up attempts)
no formation of flames
F 02 Flame extinguished (repeated >5)
F 03 Undervoltage or overvoltage
F 04 Premature flame detection
F 06 Temperature sensor interruption or
temperature sensor short-circuit
F 07 Metering pump interruption or
metering pump short-circuit
F 08 Fan motor interruption or
fan motor short-circuit or
fan motor incorrect speed
F 09 Pencil-type glow plug interruption or
pencil-type glow plug short-circuit
F 10 Overheating
F 11 Temperature limiter interruption or
temperature limiter short-circuit
F 12 Setpoint transmitter (interruption / short-circuit)

If you need the manual for an Airtop 3500 or 5000, PM me I have them in PDF format.

 

[Wunja]

Re: Webasto problems - Where should I start looking - updated

Thanks for your replies.

I had a good look today, whilst waiting for some epoxy to go off.
The clicking is coming from the relay, not the pump, and there is either an airlock in the fuel pipe twixt pump and burner or the pump is dead which is my best guess as I couldn't feel any signs of life in it.
Jim, thanks for the fault codes. Sadly this is an old model (Airtop 2400s) and only has one green LED that stays light regardless.
Darkness stopped play today, I'll have another look on my next trip to the boat.

 

[jennymckay]

Re: Webasto problems - Where should I start looking - updated

Hi Vince,

Your heavy clicking is more than likely the glow plug pulsing, which is normal. If the unit fails to combust then try pressing the re-set button (located on the top of the heater, close to the heater wiring cap). If you can hear the heater combusting but it still shuts down, this is probably a faulty flame failure probe. If, after presseing the re-set button, it still does not combust, this is probably a faulty glow plug.
One thing to remember is that the internal burning matter (fleece) is a consumable and will need replacing now and again - if this has dried out it will not function properly.
I've crawled through this unit so often I know it backwards - if you need more help send me a personal message.
Good luck! (been there and, luckily, sorted it!!)

 

[iangrant]

strip it down and clean out the heat element - you'll find it coked up, don't just dig out the coke because there is a mesh that you will damage.

Pics [image]

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[Emer]

The click does sound like the fuel pump. After about 30 secs the fan should start once the fuel is away. The flame detector will shut down if no flame kicks in, that is when the fan runs on for two mins. The glow plug id usually the first suspect and can be changed easily enough if you have access to the unit.

good luck

Hey Smeaks,

I know this is an old post but it sounds like our problem, can you help?

We're have an issue with a Thermo Top C heater. New install to a camper, Using manual switch to turn on. When I turn on the heater all appears fine exhausting fumes, heater is burning fuel after about 30 seconds a pause, internal fan on, then exhausting smoke again burner stays on for about 10 seconds then off, heater will stay on for a further 2 mins with no burner then stop. Tried on/off about 30 times same thing. Manually purged fuel pump. Pump not clicking during start up. Two plugs X1 and X2. Wiring. X1, PIN 1 SWITCH LIVE, PIN 5 NEGATIVE, PIN 6, TO PIN 1 FUEL PUMP X2, PERMANENT LIVE PIN1, NEGATIVE PIN 2. FUEL PUMP NEGATIVE PIN 2 Is the diagnostic software hard to get?
Any help appreciated
Thanks Paul (& Emer)