Webasto thermo top Z/C-D heater

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Mikedefieslife

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Does anyone have any experience with diesel water heaters?

My boat came with one, but I'm so far unable to get it to work.

It turns on and makes whirring sound for a while and emits white smoke from the exhaust (on first start). It then stops, starts again and the fuel pump starts pumping, then it runs for a few minutes without ever getting hot, then shuts off.

It looks essentially quite a simple system, but I haven't figured it out. A search turns up results mostly of car heaters e.g. BMW using canbus systems, or Rover ones tied to the cars ECU. The Webasto website is useless as all documents seems to be related to cars and talk about running the engine and whatnot.

It got down pretty cold last night so need to get it sorted as soon as I can really.
 
Mikedefieslife said:
Does anyone have any experience with diesel water heaters?

My boat came with one, but I'm so far unable to get it to work.

It turns on and makes whirring sound for a while and emits white smoke from the exhaust (on first start). It then stops, starts again and the fuel pump starts pumping, then it runs for a few minutes without ever getting hot, then shuts off.

It looks essentially quite a simple system, but I haven't figured it out. A search turns up results mostly of car heaters e.g. BMW using canbus systems, or Rover ones tied to the cars ECU. The Webasto website is useless as all documents seems to be related to cars and talk about running the engine and whatnot.

It got down pretty cold last night so need to get it sorted as soon as I can really.
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I have one the same
It runs hot water radiators
Sounds like it's trying to start but not quite getting there.
Will probably be no diesel or only small amounts with air pockets getting through.
It may be that the heater has not been run in a long time and the diesel has siphoned itself back into the tank.
It can be as simple as having to try and start it 3 or 4 times in quick succession to get sufficient diesel through.
 
No bad smell.

Do these need fuel bleeding like a diesel engine? If so I can't see any obvious way to do that. If not then presumably I can hook up an outboard style fuel bulb to prime it.
 
You can download the repair manual from the Butler Technik website - it has full troubleshooting advice, plus details of how to reset the heater after error lockout.
 
Got woken up by the ruckus caused as the polar beers chased the penguins around the boat.

Found the manuals, not particularly useful though since they seem based around installation in cars, and the troubleshooting charts tend to just say Perform Troubleshooting on Shop level, whatever that is. Think a device is used to read error codes.

The heater is definitely is using diesel as the fuel supply is going down, but it's not getting hot.
 
I bought my boat with an old DW80 diesel water heater. It didn't work at all. I spent a while getting to work and has since worked for 2 years without issue.

On my control panel is switch with a light. When it shuts down it will give flashes that tell you the error. I.e. low voltage, fuel, overheat etc. These are very useful. The fact it is firing up in the first place is a very good sign!

For comparision, mine heaters water that firstly goes into the hot water calorifier and then around the boat to various heat exchanges that blows hot air. If you get it working and yours is not rigged into the calorifier they I thoroughly recommend it! When as anchor for a few days, being able to get hot water without firing up the engine or generator is fantastic.

Also if you having got a basic matrix heater wired in parallel to you calorifier for hot air when under engine, then do so! Such a low cost and easy addition to any boat and you can get the cabin up to 25degrees in no time while motoring!!!
 
Mikedefieslife said:
The heater is definitely is using diesel as the fuel supply is going down, but it's not getting hot.
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The unit isn't getting hot or the heating isn't getting hot? If the unit is firing up getting hot to touch but the water is not hot and or not sending hot water to the heat exchangers then either you have an air block in the water circuit or your water pump isn't running.

The water in the system will be either sealed and pressurised or have a header tank like mine. Check the header tank is full if you have one. If sealed then there should be a water pressure gauge.

To refill the system I use a watering can with a hose attached and then hang it high above the whole system to create pressure to push out any air.... or you may have a little button that turns on the waterpump manually when the main heater is off. This allows you to pump water around the circuit until all the air is out.

The best guy on this forum for this type of thing is called David. Can't remember his full username but he'll reply shortly I think.
 
I have the Eberspacer equivalent, very similar to the Webasto.

If you're getting white smoke and it's not getting hot, then you're not igniting the diesel. The white smoke is unburnt diesel, you should be able to smell it.

This could be caused by:

Low voltage, it probably needs a good solid 12 volts or more at the heater, I suggest you check it with a multimeter. You could try it with a shore supplied battery charger running or run the engine on a fast tick-over to get the battery voltage up to 13.5volts or more.

If that doesn't work (or you have already tried it), it'll be a glow plug problem the glow plug has to get red hot to ignite the diesel. Either the glow plug is knackered, you can check the resistance with a multimeter on the Ohm setting, it should be low, if it's high or open circuit, you'll need a new glow plug. Or if it checks out OK, the glow plug is gummed up with carbon. This means stripping down the combustion chamber and cleaning it. You'll need a gasket set, it's difficult to reuse the old ones, and you don't want the combustion chamber to leak, it may ruin your day. I'd probably replace the glow plug at the same time, just so you know where you are.

There's probably a metal screen or gauze in front of the glow plug, this get red hot when the burner fires up and ignites the diesel once the system is running and the glow plug turns off. You have to make sure that this is relatively clean.

I'd be tempted to get an experienced Webasto/Eberspacher engineer to have a look at it if you're unsure, but be prepared to be shocked by the price of spare parts.

Diesel heater tend to like to be run at a high load/temperature, this helps keep the glow plug and screen free from carbon, i.e. it burns it off.

Once you have the burner running, the water will get hot and pump should run to circulate the hot water. Normally there are matrix heater and they will kick in once the water is hot enough, assuming that the thermostats are turned up.

I hope this helps, but if you are struggling get an engineer who knows what he's doing with diesel heaters, it'll save you time and money in the long run.

As a final point, if it is glowplug problem and you keep trying to start it, you'll be pumping diesel into the chamber. When it does eventually start-up, you'll get copious white smoke from the exhaust, until the excess diesel burns off. Just keep it running until all the white smoke has gone, and then run it some more to get the system really hot, to clear off the carbon out.
 
I've taken this apart now for a better look.

No dry carbon deposits, but the internals of the combustion chamber were wet from diesel due to the all the start attempts that I have made. There is no way to properly clean the head area of the combustion chamber. It has a wire gauze that is easily damaged, the opening is narrow and deep.

Mine doesn't look clean, but it's not full of carbon build it up either.

Now I ran a test on the glow plug. This multimeter's lowest setting was 200ohms, the test showed a resistance of 01.8. Presuming in the 200ohms range it can measure 000.0 then this looks to be the problem. Resistance on a good glow plug should be <00.4ohms.

They are £60 to replace :(
 
Mikedefieslife said:
They are £60 to replace :(
Click to expand...

That's the least of your worries with an old diesel heater. Most replacement parts are in the hundreds! OVer time i picked up 2 broken "spares and repairs" units for cheap and broke them down into usable bits. I could build a whole new unit for the price of one new flame detector or fan.
 
Installed the new glow pin, and voilla - heating. Such a joy, as the weather has been pants recently, and as ever it's good to check off a job on the ever growing list.

IMG_1516.jpg

Even if you ignore the broken ceramics that happened when removing the old one, compared to the new one, you can see it very visibly worn even though the pins ares lightly different.

Anyway, now all I need is a recommendation for a good thermostatically controlled programmable timer.
 
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More of this crap.

Heater stopped working after being on the hard for a few weeks. Opened it up and the combustion chamber was full of carbon so cleaned that out, but still a no go.

Test the glow pin which I only bought in October. Resistance on a good glow plug should be <00.4ohms. This one new one that was within tolerance before now has a resistance of 00.6ohm so outside of range.

Do car shops not see these plugs as at £60 a time it's pretty expensive. Best move might be to bin it entirely and save on the weight.
 
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