Webasto 2010 hydronic heater smoking problems

Hello all. I have a Webasto DBW 2010 with about 6000 total hours. It was rebuilt about 200 hours ago with new motor but not sure what else was done. All worked fine after the rebuild, but now I’m having the following smoking problem:

• Unit starts up and air exits the exhaust
• After about 15 seconds there is a “puff” and unit ignites, starts burning with a small amount of white smoke that seems consistent with past operations
• After about a minute the exhaust noise increases and suddenly there is a copious amount of white smoke belching out the exhaust. And I mean a lot.
• After two minutes of belching things suddenly start clearing up and after another minute no smoke is visible
• The unit runs perfectly with absolutely no smoke for as long as heat is required
• After cycling off (hydronic water is hot enough) for 5 minutes or so the identical process starts all over again as it turns on again

Any thoughts would be appreciated.

Bruce

My first guess and it’s only a guess would be the burner noozle/tip. We had to change ours once. I’d call Suremarine on Monday. Good luck.

Maybe the compressor is starting to fail also, though on my hurricane, after awhile it just wouldn’t light. My 2 cents, and I’m cheap!

Smoking is usually due to plugged up nozzles. They are about $35 and easy to change. Going for a full heat cycle at least every month keeps the nozzles clean.

The nozzle can be subject to wear or obstruction, it typically will disrupt the spray pattern, and that coupled with any misalignment of the electrodes can cause erratic ignition, that would explain the white smoke.

You should be able to take the nozzle out and get a match at a local heating supply house. Buy two, they're cheap and they can be stored indefinitely if they're kept in a dry location in the case. The nozzle should have stamped on it an angle, a letter (pattern), and flow rate in decimal. Match all 3.

Make sure the electrodes are aligned and set per spec. Sharpening the tips of the electrodes to a point can help make ignition smoother and quicker.

Bruce,

We have the same unit.

Regarding nozzles, Sure Marine told me on the first call to change the nozzle.

Problems were identified, and others continued. They were generous with their time on the phone troubleshooting.

On about the 5th call, they revealed that there were a batch of bad nozzles. They produced records indicating they sold me some of the bad nozzles. One was in the unit when I began calling them, and the second bad nozzle was used to replace that one. They eventually sent me two nozzles (new type), which solved that problem.

Please make sure you address the "bad" nozzle issue before you go in 5 other directions...

In the meantime, I am getting black smoke for about 3-5 minutes on a cold start. No other indications of trouble.

Best of luck!

Reliable starting has plagued these repurposed vehicle heaters for decades.

In a vehicle 14.4 V is common , on a boat 12,6V starting is normal.

Simplest cure is fuel with 50% kerosene

Sounds like it's not igniting right away.
As you noted, the white smoke happens when it's starting because it's supplying a lot of fuel and it's not all burning. The smoke is white because it's full of unburned diesel.
Just because you see the white smoke after the first 15 seconds does not mean it has ignited. It's simply blowing diesel through and the glow plugs might be burning some of it. It sounds like what you see after the first 15 seconds is a failed attempt to light. It then has to restart.
Listen to your fuel pump to confirm this. Every click from the pump is a drip of fuel sent to the heater. During startup you'll hear different speeds of clicks. Initially there will be a few clicks, then a bunch of clicks very close together (it's sending a bunch of fuel for startup), then the clicks will slow down as it checks to see if there's flame and tries to keep it going. You'll know if startup fails because all clicks will stop, then it will repeat.

If it's not catching right away, it's probably because your burner is sooted up. There's a tiny hole that goes right through the middle of the burner which is used for starting the heater; it lets through just the right amount of air. My exhaust line is fairly long, and I need to open up my heater about once a season to make sure this hole is clear. Even if you get a tiny piece of soot in there (the hole is only about 1mm diameter), it can cause problems with the starting process. To access this, you take the back off the heater. It'll split right where the fuel line goes in. You only have to remove a couple screws to get in there.

I had a very similar issue with a different heater (Hurricane Hydronic). The symptoms were the same. Check for air (pump), fuel (pump), spray pattern (nozzle) and ignition (igniter). Replacing the nozzle and ignition on mine resolved the problem. I also replaced the circuit board for a more advanced ‘no flame’ shut down and better diagnostic codes.

Thanks everyone for your ideas. I will get with Sure Marine tomorrow and order a nozzle and igniter. And then see if I can figure out how to change it myself. I'm sure it is probably easy to do the second time <smile>.

New nozzle is good preventive maintenance.


I'd open it up before throwing parts at it, make sure the burner chamber is clean and empty, that the sparker/igniters are clean and adjusted.


They accumulate their own dirt, plus whatever beasts crawled in there during the warm weather...



Might not need any parts...

Update - my unit was sooting horribly. Black smoke and soot. I removed the unit and sent to Sure Marine for the second time.

Sure did who knows what AND installed a new motor. They reported the black smoke on start up on their bench, also, and sent it back to me. They treated me right on the new motor and return service.

Unfortunately I am sooting up the same as before. I have ordered nozzles from another source, as I never had any sooting issues until this “batch” of nozzles from Sure Marine.

I will report further when able.

Bruce
I trust you have a good replaceable filter on the fuel feed line?

Just a thought, cuz it just happened to us. Ours wasn’t getting hot enuff and the outlet exhaust was lower than normal.
Check the air filter for the compressor. Mine was pretty dirty and after cleaning she runs like a top. By the way, on our hurricane the filter looks more like one of those brass fuel filters you find in clunk tanks.

I installed a nozzle from Heat My RV, today. Cold start of the furnace produced about 1/4 of the smoke as when started on the previous nozzle. It appeared like the light smoke as I recall before we had this last batch of nozzles from Sure Marine.

This new nozzle is gold in color and the price was right.

Will run the furnace the next couple of weekends and see how the combustion chamber looks...

I am encouraged that this new nozzle might afford the unit a cleaner burn.