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Topic: Aqua Hot smoking question (Read 2016 times) previous topic - next topic

Aqua Hot smoking question

Just cranked up the diesel burner on the AH, and it smoked pretty good for about 5 minutes, then was burning clean.  Any comments on what might be going on?

Thanks,
Mike
Mike Brady
'97 U320 SE. #5137
'13 Honda Fit
Willow Springs, MO

Re: Aqua Hot smoking question

Reply #1 –
I saw the our coach do the same earlier this year. An annual service, which included a new fuel nozzle and filter, cured it.
Bob & Nadine Hall
98 U320
07 Honda CR-V

Re: Aqua Hot smoking question

Reply #2 –
Hi Mike,

If the exhaust cleared up after a few minutes, you had flooded the burner chamber before it ignited. Under those circumstance it would be expected (though not normal) to see clouds of unburned fuel / white smoke.

You should look into why it did not ignite quickly on the first time. Lots of causes...centering around a partially plugged fuel filter, intermittent ignitor coil, intermittent control box, low fuel pump pressure, plugged fuel filter, low voltage and more.

You might follow the diagnostic trouble charts in the repair manual to see if you can narrow down the problem.

Jim
Jim Frerichs
2002 U320 42'

Re: Aqua Hot smoking question

Reply #3 –
This depends on whether you had white smoke as Mike said or black smoke.  You'd get white smoke if you had slow initial ignition.

I would think that the likeliest scenario is a marginal nozzle that needs serviced as was mentioned above.  As the nozzle wears the fuel atomization isn't as good.  When it first starts and the combustion chamber is cold the poorly atomized fuel may not mix with the air that well, burns poorly, and thus it comes out as black smoke.  A diesel engine with worn injector nozzles will smoke black too.  As it warms up combustion becomes better as the chamber becomes hotter and a more complete burn is easier with the poor atomization.  This is pretty much the behavior of ours right now and I have a new nozzle ready for it.  It could be the motor not spinning fast enough which would cause too little air, a rich burn and black smoke.  Ours smoked pretty good once when our batteries were on the low side and we were in high altitude where the air is less dense.  Voltage has to be good to the aquahot motor for everything to work properly.

Re: Aqua Hot smoking question

Reply #4 –
Sounds like the fuel shut off solenoid is leaking by. If you get smoke for a short period of time, each time it starts, look in that direction.
The selected media item is not currently available.Bob & Faith Rozek
1997 U320 40'
Xtreme Remodel
2010 Scion XD

Re: Aqua Hot smoking question

Reply #5 –
Last year ours did the same.  We took it to R&R in Spokane and a new nozzle solved the problem.
But I am surpised how fast the nozzle wore as the AH was quite new with little use??
Now, here in the frozen North and the coach firmly anchored it smokes again when I start it??  It was put down to old fuel in the lines, and maybe it has blocked the new nozzle??  I have the old one and may just clean it in brake cleaner and fit it again if the smoke persists
Cure, do not change the nozzle just before you park up for winter.
If you are somewhere warm the smoke will help to repel the Mosquitos!!!
Speedbird 1.
2001 U320 Build #5865
Daihatsu Rocky Toad
VW Touareg
'82 F100 Stepside
Beech' Debonair

Re: Aqua Hot smoking question

Reply #6 –
A little white smoke on start up and/or on shut down is not a problem.  Many do not smoke at either time but do not be concerned if yours does.  Now if the smoke on start up does not clear right away, be concerned.

The very worse thing one can do to a nozzle, especially a new nozzle (speedbird1), is to not use the diesel burner for long periods of time.  Running lots and lots of diesel through the nozzle produces almost no wear or erosion of metal to the nozzle.  But a "Worn Out" nozzle is caused by lack of use, allowing the diesel on the nozzle to congeal obstructing the super fine mist spray pattern.  Lousy spray patten means smoking, smelling or even no fire.

So, the bottom line is -- use the diesel burner once per month or more year round, stored or occupied, period.  If you let it sit and sit, plan on servicing the burner when you put the coach back in service.
Rudy Legett
2003 U320 4010 ISM 450 hp
2001 U320 4220 ISM 450 hp
1995 U320 M11 400 hp
1990 Granvilla 300 hp 3208T
Aqua Hot Service Houston and Southeast Texas

Re: Aqua Hot smoking question

Reply #7 –
Interesting rudy, I never knew that.  I noticed that at least with ours the more I use it the less it smokes.