Webasto combustion fails to accur

[Kristina]

Having an impossible time trying to get webasto new installed system to work. Got new pump and refurbished webasto, didn’t want to heat up in bucket test, sent it back the seller two times he ran it and it worked. Our diagnostics showed error flame interruption during combustion. Though ok maybe it’s voltage and bought a new loom. Finally got it working in bucket installed it and ran it once. It heated up but not loads water was hot in tap not boiling . Have the heat exchanger system with one fan and one towel radiator. Had a coolant leak overnight, topped up system and ran it for the second time. Isn’t heating up again! 
I’m attaching the diagnostics result here. Says again Flame interruption during combustion operation and after start-up has been repeated combustion still fails to accur.

there’s in no air in the system, have a second pump hooked up also, ran it with engine on, no leaks in fuel and pump is working. Primed the webasto through the program. 
really at a loss at this point, maybe someone can look with experience of reading the diagnostics and spot the issues? 

[Jess--]

Biggest problem I have seen with the diesel heaters (webasto, eberspacher, and chinese ones) that cause them to not start up is not enough power (heater plug doesn't get hot enough & fan isn't fast enough to keep combustion going).

Usually accompanied by white smoke from the exhaust (unburnt fuel + smoke)

 

usually caused by long runs on the power cables & voltage drop along them or poor negative (it should go back to the battery not to your hull).

 

As a quick test run an extra pair of power cables (in addition to what's there) and see if it will fire up, if it does then you know that you need thicker power cables for a permanent fix.

 

If it does fire up after a failed start or two expect smoke from the exhaust as it burns off the fuel from the failures, it should clear within a couple of minutes.

[Kristina]

Tried this already on the new loom, ran with engine on also. 

[Chewbacka]

A question for the seller is when they say ‘it ran ok’ for how long did they run it?  

[Kristina]

Don’t know how long but they did a bucket test and sent me a video and their dip Gnostics showed it starts up and goes up in temperature 

[Chewbacka]

21 minutes ago, Kristina said:

Don’t know how long but they did a bucket test and sent me a video and their dip Gnostics showed it starts up and goes up in temperature 

From your initial post it sounds like it runs for several minutes before failing, whereas the sellers test may have been shorter and did not find the problem.

 

I bought my Webasto from Butler Technik Ltd and found them to be very helpful.  I have not used their diagnostics and repairs service, but if I had a problem like yours, I probably would.

 

Maybe give them a call, or use the link.

https://www.butlertechnik.com/butler-technik-eberspacher-and-webasto-heater-repair-service-i101

Added - if yours was originally a vehicle heater they can also reconfigure it to settings appropriate for a boat.

 

Edited October 5, 2022 by Chewbacka

[nicknorman]

Could it just be a bit of air getting into the diesel feed? Air bubble = flame goes out, system shuts down.

[Cheshire cat]

I had a problem with crap in the fuel line after covid. I flushed the line and its been ok since. I currently dont have a filter on the heater fuel line. It's on the "to do"list. 

 

Nick's suggestion is a possibility. Air lock in the system would have the same effect if the webasto is a high point on the system. I had that problem when I changed the antifreeze.

[Midnight]

When we installed my Webasto Thermotop C last year we had a similar problem which turned out to be an air lock in the pipes.

[Kristina]

10 hours ago, nicknorman said:

Could it just be a bit of air getting into the diesel feed? Air bubble = flame goes out, system shuts down.

Tried with clean can of fuel etc. 

23 minutes ago, Midnight said:

When we installed my Webasto Thermotop C last year we had a similar problem which turned out to be an air lock in the pipes.

System pumped through with extra pump thoroughly it’s not an air lock  

[MtB]

12 hours ago, Jess-- said:

As a quick test run an extra pair of power cables (in addition to what's there) and see if it will fire up, if it does then you know that you need thicker power cables for a permanent fix.

 

An even quicker and more helpful test is to measure the terminal voltage during the start-up sequence where the supply cable connects into the Webby. This will rule in or rule out everything to do with the power supply wiring, new loom or not. I expect it needs to be 12.0V or higher but the manual will probably give a minimum value in the fault-tracing section. 

[Tracy D'arth]

2 minutes ago, MtB said:

 

An even quicker and more helpful test is to measure the terminal voltage during the start-up sequence where the supply cable connects into the Webby. This will rule in or rule out everything to do with the power supply wiring, new loom or not. I expect it needs to be 12.0V or higher but the manual will probably give a minimum value in the fault-tracing section. 

If its an ex truck one that has not been reprogrammed for a boat, it will shut down at a lower voltage than a boat one would anyway.

[MtB]

 

 

 

6 minutes ago, Kristina said:

Tried with clean can of fuel etc. 

System pumped through with extra pump thoroughly it’s not an air lock  

 

This is flawed thinking. Yes pumping through with an extra pump massively reduces the chances of it being an air lock, but you cannot state with absolute certainty it is not an air lock. There might be an air leak in the pipework (as suggested earlier by NN) which re-establishes the air lock the instant you take the extra pump off, for example. 

 

Similarly with your 'new wiring loom'. Just because you replaced the wires does not mean the input terminal voltage is now definitely high enough. It could be too low with the new wiring too. Measure it! 

[MtB]

 

 

 

9 minutes ago, Tracy D'arth said:

If its an ex truck one that has not been reprogrammed for a boat, it will shut down at a lower voltage than a boat one would anyway.

 

 

Good point, given the OP says it is a reconditioned one. My money is still on inadequate power supply. The symptoms are consistent with shagged out (technical term) batteries if this is a truck unit. The startup current drags them down but it still lights, but as the heater plug stays ON for quite a while after ignition it continues to cane a knackered battery and soon the voltage drops to cut-out voltage, and the unit shuts down.

 

 

 

Edited October 5, 2022 by MtB
Refine it

[MtB]

10 minutes ago, Tracy D'arth said:

If its an ex truck one that has not been reprogrammed for a boat, it will shut down at a lower voltage than a boat one would anyway.

 

 

Point of Order...

 

A truck one would shut down at a HIGHER voltage than a boat one, Shirley. 

 

 But I think that's what you meant! 

[Kristina]

8 hours ago, MtB said:

 

 

 

 

This is flawed thinking. Yes pumping through with an extra pump massively reduces the chances of it being an air lock, but you cannot state with absolute certainty it is not an air lock. There might be an air leak in the pipework (as suggested earlier by NN) which re-establishes the air lock the instant you take the extra pump off, for example. 

 

Similarly with your 'new wiring loom'. Just because you replaced the wires does not mean the input terminal voltage is now definitely high enough. It could be too low with the new wiring too. Measure it! 

It’s not acting like an air lock. There’s no leak anywhere for certain system pumps through and has been bled multiple times. Voltage shows as high enough on the diagnostics kept close eye on it several times . 

8 hours ago, MtB said:

 

 

Point of Order...

 

A truck one would shut down at a HIGHER voltage than a boat one, Shirley. 

 

 But I think that's what you meant! 

It’s a boat webasto 

8 hours ago, MtB said:

 

 

 

 

 

Good point, given the OP says it is a reconditioned one. My money is still on inadequate power supply. The symptoms are consistent with shagged out (technical term) batteries if this is a truck unit. The startup current drags them down but it still lights, but as the heater plug stays ON for quite a while after ignition it continues to cane a knackered battery and soon the voltage drops to cut-out voltage, and the unit shuts down.

 

 

Voltage doesn’t go down enough to cut it out, watched it closely and ran with engine on.  

[Kristina]

8 hours ago, MtB said:

 

 

 

 

 

Good point, given the OP says it is a reconditioned one. My money is still on inadequate power supply. The symptoms are consistent with shagged out (technical term) batteries if this is a truck unit. The startup current drags them down but it still lights, but as the heater plug stays ON for quite a while after ignition it continues to cane a knackered battery and soon the voltage drops to cut-out voltage, and the unit shuts down.

 

 

I understand that running the engine while it’s on should of then resolved the issue if the batteries are not good to give it more power. Also watching the voltage during diagnostics and it doesn’t drop low. 

[blackrose]

9 hours ago, Kristina said:

 

System pumped through with extra pump thoroughly it’s not an air lock  

 

But you said you'd had a coolant leak. Was that from the heater itself or from your plumbing? If the plumbing is unreliable then how can you be sure there isn't air in the system? Also what do you mean by "extra pump"? Assuming there's no bleed valve in the system all you should need to do is slide the return hose slightly off the heater spigot until there's a small gap to bleed the air out of the system. I don't see how an extra pump will help? The heater's pump should be perfectly adequate to do that job.

9 hours ago, MtB said:

 

 

Point of Order...

 

A truck one would shut down at a HIGHER voltage than a boat one, Shirley. 

 

 But I think that's what you meant! 

 

Tracy was correct. It would also shut down at a LOWER voltage. The automotive models are designed to be run with fully charged batteries, marine units can cope with slightly lower voltages.

Edited October 6, 2022 by blackrose

[matty40s]

Looking at the 3 screens, your problem is the units parameters(ie, it's a truck one).

The unit faults out at 13.99, your boat alternator will be producing well over 14 if the batteries are low.

[Tony Brooks]

30 minutes ago, matty40s said:

Looking at the 3 screens, your problem is the units parameters(ie, it's a truck one).

The unit faults out at 13.99, your boat alternator will be producing well over 14 if the batteries are low.

 

It also showed a voltage of 11.88 on the flame failure screen. Even given the glow plug load that seems rather low for a domestic bank in good order and well charged. The question is did it really shut down on a flame failure or did it shut down on low voltage. I don't know enough about their intricacies to pass a comment, but shut down at 11.88 volts makes me suspect an automotive computer map.

 

However, if the engine is running and charging that voltage suggests a wiring problem - volt drop between battery and unit.

Edited October 6, 2022 by Tony Brooks

[Kristina]

39 minutes ago, matty40s said:

Looking at the 3 screens, your problem is the units parameters(ie, it's a truck one).

The unit faults out at 13.99, your boat alternator will be producing well over 14 if the batteries are low.

Have been assured it’s a boat one by seller also this is the specs the diagnostics shows. I doubt that I’m getting so scammed that the seller tested it twice himself and still sent it back working and also it worked in bucket on our end and heated up one time 

[BEngo]

Can anyone explain to me why so many posters get good, experience based, practical advice and either just ignore it or argue against it?

 

N

[Kristina]

1 hour ago, blackrose said:

 

But you said you'd had a coolant leak. Was that from the heater itself or from your plumbing? If the plumbing is unreliable then how can you be sure there isn't air in the system? Also what do you mean by "extra pump"? Assuming there's no bleed valve in the system all you should need to do is slide the return hose slightly off the heater spigot until there's a small gap to bleed the air out of the system. I don't see how an extra pump will help? The heater's pump should be perfectly adequate to do that job.

 

Tracy was correct. It would also shut down at a LOWER voltage. The automotive models are designed to be run with fully charged batteries, marine units can cope with slightly lower voltages.

Leak was near radiator at straight connector, it has been tightened. No leaks anywhere also in system. System was bled through thoroughly several times air released if there was any at radiator and header tank. It’s nit acting like an air lock which we had before and fixed. Can see coolant pumping through the system. There’s no way air is getting in magically into the coolant system there are no leaks to suggest this. 

Just now, BEngo said:

Can anyone explain to me why so many posters get good, experience based, practical advice and either just ignore it or argue against it?

 

N

Not ignoring it literally have tried to address each of the ideas several ways multiple times now and still it’s not working 

[MtB]

6 minutes ago, BEngo said:

Can anyone explain to me why so many posters get good, experience based, practical advice and either just ignore it or argue against it?

 

N

 

Puzzling isn't it?

 

There is clearly a difference in the installation of this Webby on the test bench (where it works) and in the boat (where it doesn't). The task is to find and pin down what the difference is, but the OP simply bats away and dismisses every suggestion about areas to investigate.

 

This Webby is not going to work ever, with this approach.

 

 

 

 

Edited October 6, 2022 by MtB
Fiddle with it...

[Tony Brooks]

4 minutes ago, Kristina said:

 

Not ignoring it literally have tried to address each of the ideas several ways multiple times now and still it’s not working 

 

So have you used a decent multimeter to confirm the voltage at the glow plug during start up and at the unit's positive connection during and after start up until it cuts out.