Skip to main content ↑ ↓
Topic: Interesting Aqua Hot issue (Read 762 times) previous topic - next topic

Interesting Aqua Hot issue

Replaced my AH fuel lines with some trident fuel lines as I noticed plenty of cracks and suffered from a failure to fire. Following a few purges, my failure to fire wasn't only caused by the fuel lines. I replaced the webasto controller with the one from my parent's FT. This has seemed to fix the failure to fire problem along with quieting the AH down a bit. When my unit would allow it to fire, there was a very large influx of fuel and air causing a very noticeable increase in sound.

Now, a day later, my unit seems to be having a different issue. As it's running, the exhaust seems to sputter or puff randomly sending a small poof of either white or black smoke. It almost sounds like it's losing air for a brief moment.

I will try to upload a video and attach it.

Any ideas?

Re: Interesting Aqua Hot issue

Reply #2 –
I had a wire in/on the controller that failed.  Replacing the wire fixed it.

When my AH has puffed and smoked, I have replaced the nozzle and it fixed it - twice.

Re: Interesting Aqua Hot issue

Reply #3 –
Have you replaced the fuel filter? It definitely sounds like combustion is stalling for a brief second. I know you have new nozzles on there and a new fan motor too right?

Re: Interesting Aqua Hot issue

Reply #4 –
Quote from: Elliott –
Have you replaced the fuel filter? It definitely sounds like combustion is stalling for a brief second. I know you have new nozzles on there and a new fan motor too right?

Fuel filter was changed in April as well as the nozzle. I put another new nozzle on in june after replacing the chamber and putting the new exhaust on. I guess it's possible that it's clogged or there's some dirt somewhere especially after changing the fuel lines.

Motor wasn't changed be we did check it out by putting it on the battery.

The good thing is I have 2 more filters and 4 or 5 nozzles. :D

Re: Interesting Aqua Hot issue

Reply #5 –
Mine will do that when it first fires up until it gets hot it seems.  Once it gets up to temp, it stays steady.

Re: Interesting Aqua Hot issue

Reply #6 –
Air leak in supply fuel line will smoke and/or stutter.

Re: Interesting Aqua Hot issue

Reply #7 –
Quote from: Rudy –
Air leak in supply fuel line will smoke and/or stutter.

But I just replaced all of them. 😔 I guess I can keep running it and see if it calms down. I will likely also replace the nozzle and filter because I didn't do that at the same time as the fuel line change.

Re: Interesting Aqua Hot issue

Reply #8 –
I have seen a supply fuel line leak from a fuel filter that was over tighten distorting the square o-ring leaking air.    Running the burner on a fuel line from a container at the burner bypasses the coach fuel system.

Smoking with the container, burner problem.  No smoke, fuel line problem.

Re: Interesting Aqua Hot issue

Reply #9 –
Quote from: Rudy –
I have seen a supply fuel line leak from a fuel filter that was over tighten distorting the square o-ring leaking air.    Running the burner on a fuel line from a container at the burner bypasses the coach fuel system.

Smoking with the container, burner problem.  No smoke, fuel line problem.

Okay. Thank you. It seems like the issue is worsening as I just turned it on this evening and the puffing is happening every second or two. I'm going to go ahead and replace both the filter and nozzle tomorrow and see what happens. I didn't have this much of an issue with puffing or stuttering with the old lines that I know were bad. 

Re: Interesting Aqua Hot issue

Reply #10 –
Zach, when installing a nozzle, tighten it up, loosen it 1/4 turn and tighten it a second time.  Fuel leaking passed the nozzle threads will cause smoke.

Re: Interesting Aqua Hot issue

Reply #11 –
Why not just do what Rudy said run the burner from a container. That way you will know
if you have a air leak or not. It's a good way to trouble shoot the system.

Re: Interesting Aqua Hot issue

Reply #12 –
Quote from: oldguy –
Why not just do what Rudy said run the burner from a container. That way you will know
if you have a air leak or not. It's a good way to trouble shoot the system.

May as well do that too. Find a container and put the send fuel line in it?

Re: Interesting Aqua Hot issue

Reply #13 –
No air leaks found. Did do Rudy's suggestion and removed the fuel lines and placed the burner lines in a jar of diesel. Started and ran fine.

The issue... the fuel send line was kinked.  The fuel pump was pulling as best as it could but couldn't get fuel to the burner. Unkinked the line, let it cycle while not burning a couple of times and now it's running fine. Capacitors come in tomorrow, so hopefully I can rebuild my controller tomorrow.
 

Re: Interesting Aqua Hot issue

Reply #14 –
You shouldn't have a problem. Biggest part was removing potting material. Be careful not to damage circuit board. I had posted this prior.

The electrolytic capacitors tend to fail as they age. The capacitors determine timing, I've had several that failed to stop the blower properly and cycled on/off. I've had success replacing the capacitors however other components can fail. A schematic of the circuit board would be great but no success finding one. On the older metal enclosed controllers the connector end can be pryed off and the ciucuit board slides out.

 If you know a little about electronic circuits and you're handy soldering it may be worth trying. Cost of new controllers is ridiculous and they last 7 years or so. I have two controllers and replacing the capacitors fixed both of them.

Capacitors are available from Newark Electronics and they're cheap.

 Controller Capacitors
2 ea  220 uf  Axial  16VDC    C1 & C3
1 ea  100 uf  Radial 25V        C4
1 ea    10 uf  Axial    63V        C2
1 ea  470 uf  Radial 35V        C5
1 ea      10 uf  Axial  33V        C6

So during initial inspection i noticed that the C2 and C6 are the same value at 10uf Axial 63v
Will order extra if anyone needs PM me
My unit was working good but since I'm changing the ignition unit this would be the other weak link. Proactively changing capacitors is good in my opinion. I know no one has touched them prior to 2007, so they are old and have been threw many summers.