White smoke common from my coach

[George Frudakis]

Hi all, turn the thermostat to furnace heat. The electrical heat works well, if I leave it to long, I run out of hot water but the front of my coach blow but not hot air. So, I decided to turn on the diesel heater switch.  I have never used it, and after a while white smoke was coming from the exhaust pipe. My neighbors thought the coach was on fire. Turn it off and just used electric heat. Is it normal to have white exhaust smoke coming out like a white could or will it change to regular diesel smoke after a while.

[Steve Huber Co-Admin]

George,
An air leak can cause this condition. Other possible causes are electrodes out of alignment, a faulty fuel nozzle, low fuel pressure or bad fuel pump. If you haven't serviced the unit or used the diesel burner in quite some time I'd start with a new fuel filter as you may have gelling that is reducing fuel flow/pressure. Next on my list would be a new nozzle and electrode alignment.
Steve

[Gene Obie]

You indicated you've never used your diesel heater so their could just have been moisture inside. Could the "white smoke" just have been steam? Any water leaking around your diesel heater?

[David T. Richelderfer]

White smoke from a cold diesel engine is always seen when it is first started in the morning, especially on a very cold winter morning.  After a minute or two, it will clear up as the engine and exhaust piping warm up.  There's a problem when that white smoke doesn't show; that means the diesel didn't ignite.

 

[Fred Brooks]

   George,
 When did you last service your Aqua-Hot diesel burner and combustion chamber?
  Fred

[Eric Maclean Co-Admin]

George
I agree with all the above posts the first place to start in with a good servicing ( this should be an annual event )
Cleaning all the soot buildup from the combustion chamber makes a big difference on its own but as Steve said a full service involves a new nozzle, filters electrode set properly and a fuel pressure test and possibly adjustment .

The source of the white smoke is unburnt diesel fuel.
In an Aquahot the white smoke can be caused by several things I'll give you a list of things to check.
1) poorly aligned electrodes ( too far into the chamber disrupting the spray pattern of the nozzle)
2) a bad fuel nozzle spray pattern
3) a bad or leaking fuel cut off solenoid valve
(after a combustion event the fuel cut off solenoid closes to shut down the burner if it leaks it will flood the combustion chamber with raw fuel which will lay there until the next combustion event when it will be burnt off slowly causing the white smoke )
4) a sooted up combustion chamber will. Collect raw fuel rather than burning it completely and contribute to the white smoke)
5) a cracked combustion chamber allowing boiler antifreeze into the chamber will cause white smoke
 ( this is caused by running the boiler low on antifreeze some of the early model Aqua hots didn't have a low fluid level cut out and could suffer this failure if run low this can be tested by pressure testing the boiler with the burner and burner tube removed look for signs of antifreeze in the combustion chamber.)
 6) low battery voltage will cause the motor to run slower resulting in poor air flow as well as poor fuel pressure which will cause BLACK smoke and very quickly soot up the combustion chamber .

https://youtu.be/9p5T6ixogEk?si=3E8ZsRbkDn2p1KTL

https://youtu.be/nj_BqehNu64?si=qwYmSEgRhs-X88QF


The aqua hot will produce a small amount of white smoke on a cold startup (from a cold ambient temperature) this is normal because the boiler fluid is keeping the combustion chamber cool causing a large quench area which hinders the diesel fuel from burning completely but as the chamber comes up to temperature the white smoke should past 3 to 5 minutes .of course this is only on a dead cold startup. Once the boiler is up to temp the next burn went takes place on a warm combustion chamber and should not smoke for more than a couple of seconds .

The Aquahots tend to run rich too much fuel not enough air at elevations over 5000 ft  because the air is just a little bit thinner at elevation this can be off set by opening the air inlet apature on the bottom of the burner to allow the blower to provide more air flow. ( I leave mine open all the time with no adverse effects.

Hope this helps
Eric