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Struggling to get the Webasto Top C to start up.


Kelbs

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Just now, Wanderer Vagabond said:

They are well bigger that my little Eberspacher filter, are the two screw on top the air bleed screws? (possible source of problem:unsure:)

Yes, little bleeders.  Its only about the size of a smallish teacup. In fact the photo looks to actual be the same scale, or very close.

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5 minutes ago, bizzard said:

Yes, little bleeders.  Its only about the size of a smallish teacup. In fact the photo looks to actual be the same scale, or very close.

The filter on my Eberspacher is the size of a very small thimble, like I said, a couple of dog hairs would block it. Going back to the above filter however, if those screw haven't been bled I assume the system would remain air-locked, particularly if it is a new system with an empty filter.

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3 minutes ago, Wanderer Vagabond said:

The filter on my Eberspacher is the size of a very small thimble, like I said, a couple of dog hairs would block it. Going back to the above filter however, if those screw haven't been bled I assume the system would remain air-locked, particularly if it is a new system with an empty filter.

It might be woth while fitting one of those filter units betwwen the tank and the Eber. The pump should cope with it. They're only about £20 complete. As I said they are extremely common for domestic and industrial systems as well as on some boats, very reliable, bleeders seal well with little I think fibre type washers.

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10 hours ago, Kelbs said:

Thanks all very much for the advice. The problem is definitely that no fuel is coming through the line. 

 

There is plenty of voltage reaching the unit, I tested it earlier. 

 

 

 

First of all I very much doubt the builder fitted a dip tube inside the tank and if not that would explain no fuel. I would get a piece of stiff wire with  small right angle bend on it. push it through the bare fitting and feel for the tie walls. When  we fitted  boats we brazed/silver soldered the dip tube into the screw in fitting so we could get it out easily in case of fracture or blockage. Alternatively just try sucking on the pipe.

 

You were asked a specific question by two different people that was "What is the voltage at the glow plug/heater while it is trying to start". That requires a numerical answer, not "plenty of voltage". We have no way of knowing your competence in these matters and long experience suggests new members may not have much at first so how do we know your idea of plenty of voltage is valid - especially as you have not said if the measurement was  taken while trying to start or not. If it was not then the reading has little value diagnostic wise.

 

Give the pipe a suck, I think there is a very good chance that there is no dip tube installed.

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12 hours ago, Tony Brooks said:

First of all I very much doubt the builder fitted a dip tube inside the tank and if not that would explain no fuel. I would get a piece of stiff wire with  small right angle bend on it. push it through the bare fitting and feel for the tie walls. When  we fitted  boats we brazed/silver soldered the dip tube into the screw in fitting so we could get it out easily in case of fracture or blockage. Alternatively just try sucking on the pipe.

 

You were asked a specific question by two different people that was "What is the voltage at the glow plug/heater while it is trying to start". That requires a numerical answer, not "plenty of voltage". We have no way of knowing your competence in these matters and long experience suggests new members may not have much at first so how do we know your idea of plenty of voltage is valid - especially as you have not said if the measurement was  taken while trying to start or not. If it was not then the reading has little value diagnostic wise.

 

Give the pipe a suck, I think there is a very good chance that there is no dip tube installed.

Thanks Tony. I've managed to get fuel to the webasto, the issue was that I was screwed into the return pipe where there was no internal pipe. The other threaded weld joint, installed by the boat builder, does indeed have the internal pipe. Why would the Builder bother to weld threaded joints into the diesel tank and not fit the internal tube?

 

In terms of the voltage, so sorry to everyone I offended by not replying sooner, I don't know where the glow plug is so didn't test on the unit. I did test at the fuse point and it was around 13v, I forget exactly what it was but it was plenty I am sure, please correct me if I am wrong. I wouldn't have thought the fuel pump would have been engaging, or the unit completing cycle after cycle if it was a voltage problem. Not just my opinion but going from a collection of comments across a range of groups.

 

Now, after getting the diesel into the Webasto it still won't engage fully. I gave it three attempts since bringing the fuel through and still nada. It smoked a lot the first couple of times and the pipes and unit heated up but after it's cycle finished it still hadn't engaged.

 

I feel confident that tomorrow will be filled with success, but any advice on how to get the unit started would be great. Should I be able to turn it on first time from the programmable timer or do I need to keep removing the fuse to reset the CPU? And how long should the unit take to spring into ignition.

 

Cheers.

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36 minutes ago, Kelbs said:

I don't know where the glow plug is so didn't test on the unit. I did test at the fuse point and it was around 13v, I forget exactly what it was but it was plenty I am sure, please correct me if I am wrong.

Can I just chip in here??

Tony and others need you to give a voltage reading specifically taken during the start cycle whilst the plug is energised, so as to see the worst case including voltage drop due the high current (amps) being drawn.

 

This is his exact request:

13 hours ago, Tony Brooks said:

What is the voltage at the glow plug/heater while it is trying to start"

 

Incidentally, is yours a marine version or one originally designed for use in cars and lorries?

They each have different voltage envelopes unless modified.

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How do I access the glow plug? Do I take the top plastic case off?

 

I contacted the company I bought the refurb unit from and they said it is most likely going to be the automotive version but that most of their clients fit the units in boats and they have never had an issue.

 

I did check before I bought and they said it would be fine in a boat. They have since said they will take the item back if I decide I don't want it. Ideally I would use this one if possible as it's already plumbed in. Is it possible to use the automotive version?

 

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Well, unless a charger was on or the engine was running that 13V is highly suspect. Are the batteries in your meter fairly new? It is even more suspect if the unit was trying to start at the time. 13 volts would be obtainable on a set of batteries that had just come off charge as long as no load was applied to them but when the heater glow plug load was applied the voltage should have quickly dropped to around 12.7 to 12.8. After four attempts to start it should definitely be around those values.

 

If the wiring between the heater fuse and heater itself was provided by the manufacturer then we can assume whatever voltage was there would also be reasonably close to the glow plug voltage but if you purchased the connecting cable then it might be undersized for its run length. Then it would cause voltdrop so the glow plug may not get hot enough. It would also give a low voltage at the heater itself and there in may be a problem. As I understand it the under voltage cut-out value for marine units is set a little lower than automotive ones so if yours is an automotive unit AND if you have discharged batteries or undersized wiring the under voltage cut-out could be operating.

 

Now you have fuel at the heater how much smoke does it make while trying to start?

 

No smoke = no fuel or such a low voltage the glow plug can't even vaporize any.

Smoke but not much = glow plug voltage low

Clouds of smoke = may be too much fuel build up or some other fault (can't help you here as I hate the things and would not have one)

 

Not an Ebay bargain by any chance! If so what other answer were you expecting!

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It wasn't an eBay bargin it was sold by a reputable Webasto refurbishment company. Although it was cheaper than a new unit it still cost a decent chunk of money.

 

The wiring loom was built to Webasto spec so should all be fine.

 

I have 660 amps of battery bank and over 1000w of solar charging these. I know this is sufficient and can see on the victron app on my phone what the voltage of the battery bank is, as well as putting the volt meter on the bank itself.

 

I will try again after work today once the batteries have had a full day of sun and should be up around 14v. 

 

There was a LOT of smoke on the first attempt then by the third and final for last night there wasn't any really. 

 

Will update later.

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1 hour ago, Kelbs said:

It wasn't an eBay bargin it was sold by a reputable Webasto refurbishment company. Although it was cheaper than a new unit it still cost a decent chunk of money.

 

The wiring loom was built to Webasto spec so should all be fine.

 

I have 660 amps of battery bank and over 1000w of solar charging these. I know this is sufficient and can see on the victron app on my phone what the voltage of the battery bank is, as well as putting the volt meter on the bank itself.

 

I will try again after work today once the batteries have had a full day of sun and should be up around 14v. 

 

There was a LOT of smoke on the first attempt then by the third and final for last night there wasn't any really. 

 

Will update later.

Now you tell us you have loads of solar that 13V when trying to start looks perfectly plausible as long as there was reasonable daylight and in my view should be enough to start the heater.

 

Paragraph 4 - No, No, no. The batteries will not be around 14 volts. You may well have 14 volts being delivered by the solar system but that is different to battery voltage. Battery voltage is only a reliable indicator of degree of charge when the batteries have been off charge for many hours and no load has been applied or they are off charge and a reasonable load has been applied for a few minutes. However 14 volts at batteries and 13 volts at Webasto fuse WHEN STARTING should be plenty to start the heater but that indicates a 1V voltdrop between batteries and fuse which is far from ideal. If the 14V and 13V were taken with different amounts of daylight then you can not compare or use the readings.

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Checked batteries when I got back from work and they were 13.3v, same at the Webasto fuse board. I tried to start it up another 4/5 times with no joy. I have tried restarting the unit by disconnecting the main heater wires, as recommended, and checked the exhaust pipe for excess fuel. Still the unit will not start up.

 

One thought I have had is that the very first rad on the system has a TRV attached, I used it because it came free with the rad and it is out of sight. I know you aren't supposed to use TRV's with the Webasto system but I assumed it would be fine if left open. Does anyone have any experience with this? 

 

I contacted the seller earlier to ask for his opinion and he had this to say (amongst other things):

 

'Webasto claims that boats should have units that are capable working at lower voltages. Automotive units will work with batteries drained to 10.04v, 'marine' one can go down to 9.76v. Is it really the issue? All power inverters cut out at 10.5v to protect batteries, so would you want to drain your batteries to 9.76? That would make webasto work extra 5minutes before it cuts out and would cause permanent damage to batteries. Batteries aren't supposed to go below 11v or it will permanently damage them and reduce capacity. Other thing is most boats are on hookup all year round and voltage never drops below 13.2v."

 

Any one know what I should try now? 

 

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4 minutes ago, Kelbs said:

Checked batteries when I got back from work and they were 13.3v, same at the Webasto fuse board. I tried to start it up another 4/5 times with no joy. I have tried restarting the unit by disconnecting the main heater wires, as recommended, and checked the exhaust pipe for excess fuel. Still the unit will not start up.

 

One thought I have had is that the very first rad on the system has a TRV attached, I used it because it came free with the rad and it is out of sight. I know you aren't supposed to use TRV's with the Webasto system but I assumed it would be fine if left open. Does anyone have any experience with this? 

 

I contacted the seller earlier to ask for his opinion and he had this to say (amongst other things):

 

'Webasto claims that boats should have units that are capable working at lower voltages. Automotive units will work with batteries drained to 10.04v, 'marine' one can go down to 9.76v. Is it really the issue? All power inverters cut out at 10.5v to protect batteries, so would you want to drain your batteries to 9.76? That would make webasto work extra 5minutes before it cuts out and would cause permanent damage to batteries. Batteries aren't supposed to go below 11v or it will permanently damage them and reduce capacity. Other thing is most boats are on hookup all year round and voltage never drops below 13.2v."

 

Any one know what I should try now? 

 

The TRV will not be an issue re starting. It might become an issue if it restricted the flow enough for the heater to eventually overheat.

 

I think the fuel flows into a sport of gauze covered pot in the modern heaters (unlike Webastos of the late 60s) so I can't see why you should expect to see fuel at the exhaust outlet.

 

I think I would measure the voltage at the glow plug terminals when it is starting and if you get in excess of 12V there take the plug out, connect the wires and try to start it to see if the plug glows brightly enough to ignite diesel..

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7 minutes ago, Tony Brooks said:

The TRV will not be an issue re starting. It might become an issue if it restricted the flow enough for the heater to eventually overheat.

 

I think the fuel flows into a sport of gauze covered pot in the modern heaters (unlike Webastos of the late 60s) so I can't see why you should expect to see fuel at the exhaust outlet.

 

I think I would measure the voltage at the glow plug terminals when it is starting and if you get in excess of 12V there take the plug out, connect the wires and try to start it to see if the plug glows brightly enough to ignite diesel..

Cheers Tony. Will try this tomorrow. 

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13 hours ago, Kelbs said:

It wasn't an eBay bargin it was sold by a reputable Webasto refurbishment company. Although it was cheaper than a new unit it still cost a decent chunk of money.

 

The wiring loom was built to Webasto spec so should all be fine.

 

I have 660 amps of battery bank and over 1000w of solar charging these. I know this is sufficient and can see on the victron app on my phone what the voltage of the battery bank is, as well as putting the volt meter on the bank itself.

 

I will try again after work today once the batteries have had a full day of sun and should be up around 14v. 

 

There was a LOT of smoke on the first attempt then by the third and final for last night there wasn't any really. 

 

Will update later.

Mine is an ebay bargain. A seller with the user name MP and H. he has 817 positive feedbacks, all for webasto units he has sold, superb service and price. i bought two and have one as a spare. Starts first time every time and works without fault and going into third winter now for less than half price of pukka unit. Had first one serviced by same guy for peanuts and returned within 48 hours. I am not alone. Just sayin like.

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14 minutes ago, mrsmelly said:

Mine is an ebay bargain. A seller with the user name MP and H. he has 817 positive feedbacks, all for webasto units he has sold, superb service and price. i bought two and have one as a spare. Starts first time every time and works without fault and going into third winter now for less than half price of pukka unit. Had first one serviced by same guy for peanuts and returned within 48 hours. I am not alone. Just sayin like.

That's who I got mine from. 

 

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1 hour ago, Kelbs said:

Checked batteries when I got back from work and they were 13.3v, same at the Webasto fuse board.

Completely irrelevant. What is the voltage on the glow plug when it’s attempting to start?  A surface charge of 13.3V at some distance removed from the unit prior to starting it tells you nothing about undersized cables, faulty connections or a faulty glowplug. 

1 hour ago, Kelbs said:

... would you want to drain your batteries to 9.76?

Again, this is missing the point by a country mile. Has he never heard of voltage drop down a cable?

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23 minutes ago, WotEver said:

Again, this is missing the point by a country mile. Has he never heard of voltage drop down a cable?

I tried to explain this point really carefully way back in #31.

As you know, he has been been asked many times, but there seems to be some sort of block on the specific point of supplying a voltage reading during startup. It’s as if the OP thinks he understands perfectly that this is not the problem, so ignores it repeatedly, thus preventing it being eliminated as a possible issue?

The solar factor has further complicated this.

Of course I may well be speaking out my rear end (but in this case perhaps not?)

Edited by gbclive
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10 minutes ago, gbclive said:

I tried to explain this point really carefully way back in #31.

As you know, he has been been asked many times, but there seems to be some sort of block on the specific point of supplying a voltage reading during startup. It’s as if the OP thinks he understands perfectly that this is not the problem, so ignores it repeatedly, thus preventing it being eliminated as a possible issue?

The solar factor has further complicated this.

Of course I may well be speaking out my rear end (but in this case perhaps not?)

No, you’re missing nothing. Perhaps the cabling and supply is perfect but until that is confirmed we’ll all be suspecting it as a possible cause, particularly because the symptoms are classic of a low voltage at the unit. 

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3 hours ago, Kelbs said:

Checked batteries when I got back from work and they were 13.3v, same at the Webasto fuse board.

 

As other keep saying, this reading is irrelevant.

 

What is the voltage AT THE GLOW PLUG TERMINAL  for the n'th time, DURING THE START-UP CYCLE?

 

 

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7 hours ago, Mike the Boilerman said:

 

As other keep saying, this reading is irrelevant.

 

What is the voltage AT THE GLOW PLUG TERMINAL  for the n'th time, DURING THE START-UP CYCLE?

 

 

Again, I don't know where the glow plug is. Perhaps if someone could tell me then I could check. I'm not just ignoring the matter but I think I'd have to crack open the casing to find the glow plug. 

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Also, the unit gets very very hot and starts to warm the water pipes. I may be wrong but if smoke is coming out of the exhaust and the unit is heating up would that not mean the glow plug works? Is the glow plug only used in start up or is it on the whole time the unit is on?

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This page shows the  glow plug kit and the burner & glow plug assembly so that might give you a clue as to where to start looking.

 

https://www.cabin-connect.co.uk/ProductGrp/webasto-thermo-top-c

 

But I would have hoped that this would have been in the "manual" supplied with your heater.

2 minutes ago, Kelbs said:

Also, the unit gets very very hot and starts to warm the water pipes. I may be wrong but if smoke is coming out of the exhaust and the unit is heating up would that not mean the glow plug works? Is the glow plug only used in start up or is it on the whole time the unit is on?

Now you add a vital bit of information.

 

That suggest an over heat shutdown which in turn suggest lack of water circulation so:-

 

Lack of water, airlock, valve turned off, restriction to flow and so on. With that last bit of information the TRV might be an issue.

 

Why oh why do we have to try to drag info out of  people with [problems or only get fed vital bits of info in dribs and drabs.

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On pumped wet systems like this the main pipe runs are usually at or close to floor level while the heater is often mounted above the uxter plate so may be 2ft or more higher. This is a sure fire recipe for an airlock in the horizontal pipes that leave the heater. It is even worse if there is a slight uphill slope leaving the heater. If I were fitting one I would fit an air bleed pint at the highest point in both horizontal runs but the hot outlet one is probably more important. That is unless a vent is fitted at the highest point, not a filler, an open vent.

 

To say any more needs a carefully drawn diagram showing the whole system and exactly the angles and how the pipes run.

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I think Tony may have something there. I changed my radiators and ended up with an airlock in the webasto. It fired up and heated up water in the immediate vicinity but couldn't pump it around the system. I can't remember the symptoms in terms of whether it shut itself down or not but the solution was to pull one of the water hoses off the webasto allowing it to back fill from the header tank. 

 

Once I did that everything worked as expected. Be careful not to get scalded. The water "trapped" in the Webasto was very hot.

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