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Webasto Start-up Problem


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Hi All,

 

I've got a Webasto Thermotop C, it's been in for over a year and running with no problems, running rads in winter, and water (with a couple of rads) all summer. But typically just before winter it's decided to start playing up and won't start. It's installed to the letter from the marine install guide I was sent through here.

 

When I turn it on it whirs for a bit, then goes quiet, the fuel pump starts ticking then it starts up and the pump speeds up but then goes into shut down mode, sometimes it shuts down before the pump speeds up. While it's doing this it can put out quite a bit of smoke and it smells a bit more like diesel than I remember. The first couple of times it did this it started on the second try, but yesterday I must have tried it about 5-6 times and it wouldn't get started.

 

Any ideas?

 

Thanks

Steve

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Hi All,

 

I've got a Webasto Thermotop C, it's been in for over a year and running with no problems, running rads in winter, and water (with a couple of rads) all summer. But typically just before winter it's decided to start playing up and won't start. It's installed to the letter from the marine install guide I was sent through here.

 

When I turn it on it whirs for a bit, then goes quiet, the fuel pump starts ticking then it starts up and the pump speeds up but then goes into shut down mode, sometimes it shuts down before the pump speeds up. While it's doing this it can put out quite a bit of smoke and it smells a bit more like diesel than I remember. The first couple of times it did this it started on the second try, but yesterday I must have tried it about 5-6 times and it wouldn't get started.

 

Any ideas?

 

Thanks

Steve

 

Hi

 

Whip it off and send it for a service before it gets tooooo cold brrrr

 

Tim

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I'm hoping this is something I can fix myself, full service is last resort if i can't.

 

Yeah, excess fuel could well be a problem from the way it smells, I'll give that a try and report back..........

 

No, it's installed to the letter.

Edited by steve_gts
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It could be low voltage causing the problem. Check the voltage at the unit whilst starting it. The glow pin takes a hefty current during startup and may drag the voltage down if you have a bad connection or poor battery.

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Could be any number of problems. The smell of fuel will just be the fuel that it isn't igniting but is being pumped in.

 

The manual for our Webasto heating recommends running the unit for an hour a month even during the summer to draw fresh fuel into the system. Have you been doing this? It could just be that the fuel in the lines isn't fresh enough for the unit.

 

Check the voltage getting to the unit, they are very voltage sensitive.

 

Have you checked the condition of the glow plug?

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OK, I just disconnected the fuel supply and started it up to burn off any excess fuel (and check it wasn't a fuel issue at the same time), it did the usual startup and cool down. Then I connected it back up, tried restarting and the pump didn't sound at all on first try. second and third try it's working but shutting down again before the pump speeds up. It does sound like it's straining a bit just before the pump stops and goes into shutdown again.

 

I don't think it's low voltage, my batteries are sitting at almost 100% atm, with between 13.5 and 14.2v as some is coming in through the solar (it's a very good electric system and batteries), although I don't have a multimeter to test the webasto, its only about 1.5 m from batts, so shouldn't be a problem, connections all feel fine.

 

It's been run regularly all summer for hot water with no problems.

 

Is the glow plug easily accessed to check it and what would I be looking for?

Edited by steve_gts
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I just took the main fuse out and heard a little click when I did, so left it for 10 mins incase it would do a reset or something and it's started up fine, I'm going to leave it running for half an hour. Thanks for all the help!

 

I'll try it again later and see if it starts up again OK.

 

Does all this point to it needing a service though? I'd rather do it now than in the middle of winter :-/

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I just took the main fuse out and heard a little click when I did, so left it for 10 mins incase it would do a reset or something and it's started up fine, I'm going to leave it running for half an hour. Thanks for all the help!

 

I'll try it again later and see if it starts up again OK.

 

Does all this point to it needing a service though? I'd rather do it now than in the middle of winter :-/

 

Awesome good news it would appear biggrin.png personally I would service it anyway as its often the best option and as you say b4 it realy gets cold.

 

Tim

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I sought some advice from a couple of engineers who service and install these. They both said if its working fine, leave it (apart fom the fuel filter of course). They said they're good for 4/5 yrs before needing a stripdown providing they don't cycle, which mine doesn't and is controlled by the Heatmeiser roomstat/timer. Ours is approaching three years old having been installed by the previous owner but dont believe it had much use until full time last winter and occassional hot water during the summer.

 

Interestingly, after I cleaned the FAG filter, it wouldnt run for the first three attempts but gathered the pump took a while to prime. Been perfect since coming on/off twice a day.

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Shouldn't they be serviced yearly anyhow?

Mines been running faultlessly for 9 years without any servicing to the main unit, only changed the fuel filter. I suspect servicing yearly is put about by the people that do servicing, or am I being synical ?

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Mines been running faultlessly for 9 years without any servicing to the main unit, only changed the fuel filter. I suspect servicing yearly is put about by the people that do servicing, or am I being synical ?

Indeed you are, us factory approved technicians recommend as safety check which can be done by the owner annually and invasive service only when unusual things start happening, this way we can generally intervene before total breakdown and cold nether regions become an issue.

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I just took the main fuse out and heard a little click when I did, so left it for 10 mins incase it would do a reset or something and it's started up fine, I'm going to leave it running for half an hour. Thanks for all the help!

 

I'll try it again later and see if it starts up again OK.

 

Does all this point to it needing a service though? I'd rather do it now than in the middle of winter :-/

Sounds like the contacts on the fuse were causing resistance and low voltage at the heater under start conditions, removing and replacing it would have "wiped" the contact surfaces and reduced the resistance, it's one of the first things I look for as it's a cheap and easy fix, though I would use some switch cleaner and then pop some Servisol on the contacts to reduce the possibility of it recurring.

  • Greenie 1
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If the fuse has got a bit corroded to hopefully avoid a repetition you might like to give the fuse and holder a coating of "Liquid electrical tape". Its a paint on liquid that strinks as it dries and forms a conformal coating to keep moisture out. It stays flexible so you can get things apart if required. I use it all over the boat where electrical connections are vulnerable. Got mine off E Bay.

 

Top Cat

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OK, thanks will do!

 

You also mentioned "safety check which can be done by the owner annually" I guess that's in the manual? I only really looked at the install guide you sent so far, better dig it out!

Not in the install manual, even the marine one but t is pretty simple:

Check electrical supply, all contacts bright & tight, terminal crimps and cables secure (this may have prevented the OPs issue)

Check coolant connections for evidence of leaks, check pressure if closed loop system, or header tank level.

Check security and integrity of exhaust system.

Check fuel system for evidence of leaks and security of fuel lines.

Check exhaust for evidence of excess smoke during start up or running (a little during start up is acceptable)

Give the heater a wipe over if getting grubby.

Apart from hooking up the Thermotest to see all pramiters are within spec, checking the CO2 output of the exhaust and feed return temperatures that's all I do

I would also advise either adding some inhibitor or changing the AF at 2 yearly intervals.

 

Edit to add: the above is for wet systems only, blown air heaters require a more thorough safety check.

Edited by NMEA
  • Greenie 1
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In addition to NMEA's advice, above, I would check the flexible mounts.

 

I had to replace the flexible mounts on my Webasto after 8 years. They had begun to perish.

Very few are fitted with them though, not part of the standard marine kit.

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Interesting. Does that mean mine is of automative origin?

No, they are not usually fitted in automotive either, I imagine some builder thought they were a good idea (which they are in some mounting locations) at some time. I only use them if the heater is mounted on the engine room to accommodation bulkhead and even then not always if there is a wooden mounting plate fixed to it.

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