Aqua Hot Black Exhaust

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Aqua Hot Black Exhaust

February 02, 2022, 10:40:07 am

My Aqua Hot is blowing a little bit of black exhaust. I only know because I can see it on the ground. When it's running you can't tell, the exhaust looks clean. The nozzle is about 2 months old and has been running pretty much every night since I installed it. I pulled the swirler when I installed the new nozzle and it was clean, so was the combustion chamber. What's the solve here? Do I need to drop the exhaust pipe and blast it was a pressure washer?

Pic attached of the evidence. The darker spot on the ground is from running it every night since mid-December.

Re: Aqua Hot Black Exhaust

Reply #1 – February 02, 2022, 11:11:57 am

Quote from: Elliott – February 02, 2022, 10:40:07 am

My Aqua Hot is blowing a little bit of black exhaust. I only know because I can see it on the ground. When it's running you can't tell, the exhaust looks clean. The nozzle is about 2 months old and has been running pretty much every night since I installed it. I pulled the swirler when I installed the new nozzle and it was clean, so was the combustion chamber. What's the solve here? Do I need to drop the exhaust pipe and blast it was a pressure washer?

Pic attached of the evidence. The darker spot on the ground is from running it every night since mid-December.

When diesel first ignites there is usually a poof of soot. And modern bio-diesel produces more soot then pure dino-diesel. And further. Our old aqua-hot burners are WAY less efficient than aquahot burners of today. According to my aqua hot guy in Tucson. The new burners can be welded into place on the old mechanism. However, I have no idea if he is correct.

Re: Aqua Hot Black Exhaust

Reply #2 – February 02, 2022, 11:32:08 am

Mine too. Not concerned. No catalytic converter or particulate filter installed. New ones might even have DEF. Mine also has a straight pipe 2" and no muffler. And the straight tip does not blow on ground so no more Exhaust soot on ground. Still here probably but not noticeable

Re: Aqua Hot Black Exhaust

Reply #3 – February 02, 2022, 11:37:12 am

Ignore the poof. When you send a rich cloud through the campground, time for a new nozzle, typically. But you will be scarred for life, forever peering out the window to avoid repeating the indignity.

Re: Aqua Hot Black Exhaust

Reply #4 – February 02, 2022, 11:41:37 am

Glad to hear it's normal but how do you guys not get a earful from campground owners? I live close enough to California that I'm likely to have a mob with pitch forks come after me.

Re: Aqua Hot Black Exhaust

Reply #5 – February 02, 2022, 11:57:38 am

Adjust the exhaust nozzle more toward the rear and not at the ground.

After having my AH 'refurbished'; new blower motor, new fuel pump, #2 circulation pump replaced, serviced with new nozzle and igniter', it blew black smoke all of the time. Took it back, and they fixed the problem; mixture too rich. Now, on start-up, there is a short puff of black smoke which leaves the black mark on the ground, like yours. Talked with Rudy, and he said that some of the units will do that, it's just the way it is and not to worry as long as it is burning clean with no smoke while it is running. I will say that I also spoke with AH tech support, and he mentioned that with it blowing black smoke that the exhaust system can become clogged with black soot and will affect the airflow and thus the efficiency of the unit. He suggested running water through the exhaust pipe from where it begins inside the enclosed blower assembly. That one sounds like a springtime project, to me.
Mike

Re: Aqua Hot Black Exhaust

Reply #6 – February 02, 2022, 12:36:03 pm

In October, due to a miscommunication, MOT serviced my AH. ( I told them I like to do my own service ). WE also replaced my combustion chamber, which was showing wear. Even with the service, my neighbor, here at the RV Park, complained of diesel smell when I ran the unit. I prefer to run it on diesel to keep the nozzle clean and because the electricity costs a lot here in the park.
Trying to be considerate, we shut the diesel off and ran it on electric. I informed my neighbor that I had to run it on fuel, every two weeks, to keep the nozzle clean. The last time I fired it up, about a week ago, I blew LOTS of smoke for a few minutes, then it burned normally. This smoking occurred before the service, when I took the coach out of storage, for our trip. It smoked for about five minutes, then cleared up.
Yesterday, when I tried to fire up the diesel, the green light stayed on, but it would NOT fire
So.....I'm damned if I do, and damned if I don't.
If I change out the nozzle now, I will only be able to fire it up every two weeks. I guess I'll just keep it on electric for now and service it before we take off, back to the states, this spring. Then, after our trip back to Maine, it goes back into storage, and the cycle repeats itself. Maybe I should buy nozzles by the case. I find it hard to believe that we can't run some brake or carb cleaner through the nozzle, blow it out, and reuse them. Rudy told me "no".....and I do WHATEVER Rudy says

Re: Aqua Hot Black Exhaust

Reply #7 – February 02, 2022, 12:38:34 pm

That little black spot on the ground seems pretty minor to me. If some busybody in your campground complains, tell them to get a life.

We were staying in the parking lot at FOT one time early in our ownership. A newer (late 90's) coach arrived and parked next to us on the curb side. Next morning it was cool, so they fired up their AquaHot. I looked out our "dining room" window and visibility was ZERO due to the dense cloud of WHITE smoke. I opened our door and the billowing smoke cloud was so thick that I thought the other coach was on FIRE! I ran around and banged on the entry door - guy opens the door - I said WTH is going on? He's like "what are you talking about..."? I walked him around his coach and pointed to the smoke. He shrugs and says "Oh, yea, it's been doing that lately. We're here to get it looked at". Since it was the weekend and the shop was closed, we unplugged and moved to another spot on the other side of the lot.

That was our first introduction to a truly malfunctioning AquaHot. Made me much more appreciative of our rudimentary propane heaters.

Re: Aqua Hot Black Exhaust

Reply #8 – February 02, 2022, 01:04:33 pm

No black spot. No difference either, just out of sight out of mind.
I would be open to a Cadillac converter if I could find one small enough and for Diesel. Might get DW off my behind. She's way too critical worse than anybody else.

Re: Aqua Hot Black Exhaust

Reply #9 – February 02, 2022, 01:15:18 pm

I'd use a foot rake😳

Re: Aqua Hot Black Exhaust

Reply #10 – February 02, 2022, 01:22:20 pm

Elliott,

Here you go - the answer to all your problems. Well, some of them. OK, one of them.

https://www.youtube.com/watch?v=USDELMEafBA

Re: Aqua Hot Black Exhaust

Reply #11 – February 02, 2022, 01:27:56 pm

Quote from: GleamB – February 02, 2022, 12:36:03 pm

I find it hard to believe that we can't run some brake or carb cleaner through the nozzle, blow it out, and reuse them. Rudy told me "no".....and I do WHATEVER Rudy says

I was in a pinch and couldn't get a new nozzle in time for some guests that were arriving so I tried that. I can confirm is does not do jack.

Re: Aqua Hot Black Exhaust

Reply #12 – February 02, 2022, 01:30:20 pm

Quote from: Chuck & Jeannie – February 02, 2022, 01:22:20 pm

Here you go - the answer to all your problems. Well, some of them. OK, one of them.

Even at 20 years old, seeing that monstrosity on the side of my rig would make a little of me die inside. I'll stick with Tommy's idea of using the foot rake every morning.

Re: Aqua Hot Black Exhaust

Reply #13 – February 02, 2022, 01:38:47 pm

Elliot I thought you had enough battery capacity just to run electric heat anyway?

Re: Aqua Hot Black Exhaust

Reply #14 – February 02, 2022, 01:41:28 pm

Quote from: dsd – February 02, 2022, 01:38:47 pm

Elliot I thought you had enough battery capacity just to run electric heat anyway?

The wife's hair straightener and blow dryer trumps everything.

Re: Aqua Hot Black Exhaust

Reply #15 – February 02, 2022, 01:50:16 pm

Had my AH serviced in Q and one of the things they did was to check and adjust the fuel pressure. They used an interface box to plug into the unit to make it deliver fuel pressure to a gauge they installed where the nozzle goes. How are you guys checking/adjusting fuel pressure when you service them yourself?

Mine was quite low...I believe it showed about 110psi when he started and 140ish when he was done. He said he wanted 140-145. I'd imagine lower fuel pressure may cause more soot.

Re: Aqua Hot Black Exhaust

Reply #16 – February 02, 2022, 02:15:31 pm

I got rid of the black spots on the ground and can now rub my finger in a clean exhaust pipe. Threw away the small pipe and muffler and went with 2" pipe one piece. I took the whole old exhaust system to a muffler shop, laid it on the floor and asked for a 2" pipe bent to match. The only issue was cutting some slots in the pipe at the aqua hot elbow to get a good clamp.

Re: Aqua Hot Black Exhaust

Reply #17 – February 02, 2022, 06:27:17 pm

Quote from: craneman – February 02, 2022, 02:15:31 pm

I got rid of the black spots on the ground and can now rub my finger in a clean exhaust pipe. Threw away the small pipe and muffler and went with 2" pipe one piece. I took the whole old exhaust system to a muffler shop, laid it on the floor and asked for a 2" pipe bent to match. The only issue was cutting some slots in the pipe at the aqua hot elbow to get a good clamp.

I actually had unscrewed if from the aqua hot. 2" diameter per Rudy, no muffler but it is notably louder than before. Ill have to check the inside for soot. Put exhaust rap to the tip. Had to turn the steering to the right to get it to clear the left front tire. Also opened up the air control valve/port to full open.
Scott

Re: Aqua Hot Black Exhaust

Reply #18 – February 02, 2022, 08:11:03 pm

Elliott, Make sure your air shutter on the bottom of the burner is at least 1/2 open. The phillips screw should point straight into the side of the burner or even moved more toward the tank. The burner is not sensitive to too much air but is really is to too little air.

Re: Aqua Hot Black Exhaust

Reply #19 – February 02, 2022, 08:49:57 pm

Quote from: craneman – February 02, 2022, 02:15:31 pm

I got rid of the black spots on the ground and can now rub my finger in a clean exhaust pipe

Well I looked at mine and was surprising clean and actually had a little rust on the inside. Would of lost that bet.

Re: Aqua Hot Black Exhaust

Reply #20 – February 02, 2022, 09:18:41 pm

I had problems years ago with my aquahot in a 95 u320 blowing black smoke and melting the combustion swirler. Talked with the Aquahot guy at an FMCA rally. He thought it wasn't blowing enough combustion air and suggested checking the impeller clearance. He recommended a clearance of one sheet of paper for the impeller which I believe is less than whats listed in the service manual. Worked like a charm, no more melted swirlers and minimal smoke. Bottom line soot means not enough air or too much fuel. There'll always be some amount of soot but if it's visible smoke that's not right.
It's easy to make a fuel pressure guage to check fuel pressure. Take an old fuel nozzle, drill it out then braze a bushing to the nozzle for a pressure gauge to screw into. Set the fuel pressure per the service manual, once set it typically doesn't change, I check it during annual maintenance. Air flow is controlled by a rotating shutter on the bottom of the Webasto housing. Learning to take care of your aquahot will save a bunch of money and grief on the road. it seems a lot of shops don't understand aquahot systems but they'll take your money. It's really a pretty simple device once you understand the mechanics. Use a reputable guy like Rudy if you need help.

Re: Aqua Hot Black Exhaust

Reply #21 – February 02, 2022, 11:06:00 pm

Quote from: Elliott – February 02, 2022, 11:41:37 am

Glad to hear it's normal but how do you guys not get a earful from campground owners? I live close enough to California that I'm likely to have a mob with pitch forks come after me.

I have a genturi on my aqua-hot exhaust and the exhaust now exits above roof level.

Re: Aqua Hot Black Exhaust

Reply #22 – February 03, 2022, 08:45:40 am

Elliot; when we were in Yellowstone NP last year, the AH ran from April till the time I left in late October. There was soot on the ground and I was worried that we were having another issue with the bunner, but it seems to have been the elevation we were at. Now, here in TN, the AH has run continuously and no soot. Like Rudy said, check your air shutter, could be the issue. Hope this helps!

Re: Aqua Hot Black Exhaust

Reply #23 – February 03, 2022, 10:24:27 am

Quote from: juicesqueezer – February 03, 2022, 08:45:40 am

Elliot; when we were in Yellowstone NP last year, the AH ran from April till the time I left in late October. There was soot on the ground and I was worried that we were having another issue with the bunner, but it seems to have been the elevation we were at. Now, here in TN, the AH has run continuously and no soot. Like Rudy said, check your air shutter, could be the issue. Hope this helps!

Great idea regarding the elevation. We're at 6000' here. I'll crawl under their and open the shutter like Rudy suggests and see what happens.

On a loosely related note, I have noticed that the coach also requires the boost switch to start when we're at home. Once we drop off the mountain she fires right up after maybe two turns, with no boost. I have always chalked that up to elevation too.

Re: Aqua Hot Black Exhaust

Reply #24 – February 03, 2022, 12:53:31 pm

Can you use Camco Genturi with a slide?
How long do they " hold up?"
Anyone try and make one themselves?

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