I hate Webasto and Aqua Hot's, whomever was engineering these should be retired

[KenEhresman]

OK, so after another episode of extreme RV'ing to Michigan in the snow, I'm reminded of one ares's most converters lack any talented engineers and the products they do use are JUNK!!!!

Once again, after rebuilding for the 3rd time, my POS Webasto isn't working right.... I have read, and studied all the material and restore and enjoy antique cars, so I know my way around a garage and tools. Last go around, I meticulously made a fuel pressure gauge and adjusted the fuel pressure per the specs. I even went as far to perform this pressure test at 35degrees and 100Degress to find the "right calibration point....changed the bearings for the second time, nozzle, and adjusted the distance on fan to correct specs.... after that rebuilt it ran PERFECT!!!! then all the sudden, here comes the black smoke again.... flame outs and issues.... I have 2 spare controllers I have swapped in, but I know the black smoke is a pressure fuel pattern, air supply issue... so I guess I'll have another run at this piece of crap.... this will be about 10 now...

But on a different note, someone PLEASE explain to my how my 2000 vantare can run down the road for 4 hours and heat the water in the Aquahot, but for the life of me I cannot get any heat to the heat exchangers inside the coach.... well not any heat to speak of.... it isn't cold, but it isn't hot either... when the unit runs and fires, I get heat... what the heck....

Things I have checked...

1. Yes, the circulation pumps all appear at least to be running when the thermostat calls for heat.
2. Yes, the engine is circulating coolant to the unit, remember I get hot water, like normal hot, not luke warm...
3. I have tried it with the engine circulation pump running and not ( engine pre heat) doesn't make any difference...
4. I have verified the internal coolant is at proper level...
5. I have brought the system to full temp on the internal Hot Water Electric Element, (12 hours) then kicked on the heat exchangers and I
have heat but obviously the little heating element can't keep up and it sucks off the heat in an hour or less...

What I really need more than anything, for our use, is to be able to get heat from 12V ( this is the dirty repairs again I will be doing)
and also need to get heat running down the road.... I'm about half tempted at this point to install another salvaged heat exchanger from a wrecked coach I can plumb into the coolant loop for the dash, because it will bake you out of your seat....

[Dtjoint]

Hi Ken,

Look for low voltage at the unit while running. Could be on either the positive or the ground side. On my Webasto I had intermittent failure issues and found both the grounds corroded and a bad crimp where the converter (CC) added the nozzle heater. Once those were fixed the unit has worked properly ever since. I also found and fixed a minor crack in the fuel return line but doubt if that was effecting performance. I saw proper voltage at the connector at the base of the control box at times and low voltage,other times. At one point I thought the motor was bad so replaced the motor (it was fine if anyone wants one) and the control box (likely also fine) before locating the root cause.

[KenEhresman]

Thanks Jerry, I'll get out my better Scopemeter that can capture and record and put it on and then run some cycles and see what it says as it cycles through... if it is doing that I'll catch it on the playback.

thx

[KenEhresman]

Ok, Aqua hot running once again... Talk about dangerouse, the input shaft on the fuel pump was worn and the seal shot and it was leaking fuel into the blower housing then down into the tray..... lucky it didn't ignite... replaced fuel pump with a spare used one, adjusted to 135 cold and put back together...

FWIW, i'm becoming somewhat of an expert on these since I have torn mine down so many times.... here is a list of very common failures I have come across

1. The Bearing wear out and the motor then doesn't spin correctly, catch it early and you are fine replacing them
2. The fuel pump has more than one issue, the input shaft seal as mentioned above, check all 4 top plate torx to ensure they are tight, have seen them loose, the o-ring under that cover also fails... all pretty easy fixes..
3. The plastic motor couplers fail at the input shaft, they are simple D shaped input shaft but then spin out resulting in no fan, or very low fan.
4. Diode failure on input to controller...

I have 2 extra controllers, a bunch of motors, coils, etc... so if anyone ever needs parts let me know.. some can be found on eBay but are expensive and rarely pop up... At this point I'd probably drop a couple grand on a brand new head, but can only find refurbs....MY .02 cents, if you have to service it, do it all, the first time... bearings, Seals, Couplers, etc... and hopefully be ok for another 100-200 hours of use.. lol

[Mike GAy]

Ok, Aqua hot running once again... Talk about dangerouse, the input shaft on the fuel pump was worn and the seal shot and it was leaking fuel into the blower housing then down into the tray..... lucky it didn't ignite... replaced fuel pump with a spare used one, adjusted to 135 cold and put back together...

FWIW, i'm becoming somewhat of an expert on these since I have torn mine down so many times.... here is a list of very common failures I have come across

1. The Bearing wear out and the motor then doesn't spin correctly, catch it early and you are fine replacing them
2. The fuel pump has more than one issue, the input shaft seal as mentioned above, check all 4 top plate torx to ensure they are tight, have seen them loose, the o-ring under that cover also fails... all pretty easy fixes..
3. The plastic motor couplers fail at the input shaft, they are simple D shaped input shaft but then spin out resulting in no fan, or very low fan.
4. Diode failure on input to controller...

I have 2 extra controllers, a bunch of motors, coils, etc... so if anyone ever needs parts let me know.. some can be found on eBay but are expensive and rarely pop up... At this point I'd probably drop a couple grand on a brand new head, but can only find refurbs....MY .02 cents, if you have to service it, do it all, the first time... bearings, Seals, Couplers, etc... and hopefully be ok for another 100-200 hours of use.. lol

You folks are scaring me!! Lol!

Our first coach was a Newmar with electric water heater. We had issues.
Next coach (which we will sell after we get it repaired) is a Mandalay with Oasis WH and furnace. Again, I had to replace pumps and other issues. Mama doesn't like cold showers!!

I'm hoping the Liberty/Webasto combination is more consistent!

[Dtjoint]

Hi Mike,

No need for concern. They are robust reliable units when properly serviced. The issue is found in the term “properly serviced”. It is all too easy for even well known service folks to just change the nozzle and filter once in a while and declare it properly serviced. Just like a home oil furnace a proper service also requires a close inspection of the hoses (the connection ends get brittle with age and heat), wire connections (especially grounds), the plastic motor-to-pump and fan connector and any internal leaks. All these are easy and fast to do with the motor head assembly removed. Whether that is easy to do or not depends on where your Webasto burner head is located. Mine is in a SS box just inside the PS engine compartment side door so it is a snap to get in and out once you pass the fear factor of doing it the first time. What is not so easy is trying to diagnose the root cause issue if it fails. My suggestion is look first for external electrical problems like bad grounds or connectors. After confirming good power then go through the steps Ken suggests. Bottom line, if your Webasto works reliably now it likely will continue to do so as you use it. Do the same kind of inspection and service as you would do with a home furnace and enjoy the nice quiet heat.

jerry

[KenEhresman]

Hi Jerry and Mike,

Without sounding like Negative Nancy, I don't share Jerry's optimism on the engineering side of the Aquahot. I agree with alot of the comments, they are easy to get in and out, and once you have tore into once, it is a breeze. the challenge that I have with "trusting" these units is based on Jerry's comments about the brittle pieces and parts... as such, a diesel fired heater, the cycles will age all plastic, seals, connectors and other parts that lead to these failures. There are 2 certain things that will kill these, not using them regularly is probably the number 1 reason, and incomplete or improper service is number 2 hitting on Jerry's comments. This is why I would also recommend, when you hit certain time intervals of a "Complete" service. the challenge with the "Complete Service" is the cost. Some parts are cheap, so change them often. O-Rings, Hoses, Drive Couplers, Bearings etc... other parts not so cheap, Coil, Fuel Pump, 12V motor etc...

In my case, I bought a neglected 2000 Vantare with a LOT of deferred maintenance issues. This likely has sped along the failure of the unit, but ultimately, I think it has a life of about 20 years give or take if serviced regularly. Lots of us are at or near this life, and will likely see more than one failure in the months and years to come if we use them. A total rebuild will bring it back to life, but since I am on failure number 4-5 over the last year, I don't share any optimism it will run robustly or reliably. I mean, I don't think removing the fuel pump and inspecting it is normal maintenance, yet mine failed at the input shaft....

So, in my humble opinion, if you are at or over 20 years, I'd recommend a Full Service, changing every part that isn't a fixed part of the casing... including fuel pump, 12v motor, bearings, seals, nozzle, heater if equipped, all hoses and connectors... or better yet, if you can find one, change the entire burner head with a new one...