Community Forums

IRVSOUTH · 12-05-2022, 04:04 PM

Does anyone know what's beyond the burner wall of my Aqua-Hot AHE-100-04S?
I know there is a fire chamber, electric heat elements etc. and a glycol tank but I can't find a schematic of the inner workings anywhere. The reason I ask is that I have a coolant leak coming down the exhaust pipe hole. I put the system under pressure and it drips out very noticeably. However, on the side with the burner and zone pumps I do not have any leaks. So what is happening beyond the Great Wall of Aqua-Hot? Are there fittings that can fail or could it be the tank sprung a leak and how does one get in there? If anyone has had this issue or can shed some light here please comment. Thanks!

RichardE · 12-05-2022, 05:12 PM

It is likely one of two things. If you are lucky, the filler neck solder joint has failed and your leak is there. This is a common problem. Roger Berke sells a kit to repair the failed neck in situ. The other probability is the area where the exhaust from the burner chamber exits has corroded and sprung a leak. That is no bueno. New tank required.

Archer2 · 12-05-2022, 05:17 PM

Here’s a link to a manual with a cutaway view of an AHE-200 (Figure 3/ pg 7). Yours should be similar.

https://library.aquahot.com/wp-conte...ice-Manual.pdf

caryt · 12-06-2022, 10:27 AM

Whats leaking? Boiler fluid or diesel fuel..

BillJinOR · 12-06-2022, 10:56 AM

Behind the “wall” on the 100 series is a round boiler drum with several fittings .. lines welded into the tank.and of course the burner tube through the middle . Water to very long a copper coil wrapped tightly around the outside of that round cylinder boiler with heat transfer “goop” then insulation.
I helped a tech replace my tank .. not cheap ! If lucky as already said it’s the “radiator cap” solder joint. If not , probably a new tank. There are several welded fittings that could have failed.
FYI I paid 7500 4 years ago , and I helped and Rebuild it using most of my pumps and electronics. A factory rebuild was 10 grand at that time.

IRVSOUTH · 12-06-2022, 11:32 AM

Thanks everyone for your input!

RichardE - can you clearly see if the filler neck is cracked, how far down should I be looking?

BillJinOR - Did you pull your unit out of the coach to work on it or were you able to do it in place? Mine is in the belly of my HR Navigator 05, very tight to work in there and I'm not sure how to remove the rear portion of the SS enclosure. Any Ideas?

caryt - The leak is boiler fluid.

BillJinOR · 12-06-2022, 02:33 PM

The entire unit came out. Disconnect all lines and in my case , 4 bolts 2 from the front and two difficult ones from the back. We took the unit completely apart. It takes two reasonably able folks. I was at the s California repair facility for 5 days , he had the tank and all parts in stock .

153stars · 12-06-2022, 09:36 PM

If the burner chamber to exhaust was leaking it would want to go out the exhaust pipe and you would likely smell sweet exhaust like a car with bad head gasket. A member cut apart and rewelded his tank to replace internal fresh water heating coil, so tank can be repaired.
The cap ,its neck, overflow hose or it's metal tube is by far the most often cause of a glycol leak.

IRVSOUTH · 12-07-2022, 05:48 AM

Quote:

Originally Posted by 153stars

If the burner chamber to exhaust was leaking it would want to go out the exhaust pipe and you would likely smell sweet exhaust like a car with bad head gasket. A member cut apart and rewelded his tank to replace internal fresh water heating coil, so tank can be repaired.
The cap ,its neck, overflow hose or it's metal tube is by far the most often cause of a glycol leak.

Thank you for your reply. How would you go about isolating the neck and metal tube leak? When under pressure the coolant comes out of the same hole in the floor as the exhaust pipe not from a crack in the pipe. It could be the neck or the tank, hard to know which is which when it’s all enclosed in a SS box. Thanks again!

RichardE · 12-07-2022, 07:49 AM

So……… water or coolant tends not to run uphill.

Let’s take advantage of physics in helping you find the leak BEFORE you go to the work of tearing out the box.

Take some white paper towels and stuff them in and around the filler neck as far into the opening as you can. The green or red coolant will stain them if it is leaking there. You will have to run the unit to cause the leak. The filler neck can be repaired in place although it’s not for the faint of heart. It fails where the lip for the cap is brazed to the fill pipe. You take a MAPP torch and heat it until the solder melts and you pull the lip off. The kit then places a silicone coolant hose with clamp over the fill pipe. The coolant hose is short and has a lip for the cap on the other end. Sort of ingenious for a fix that doesn’t require removal of the unit.

If it is anything else, the unit HAS to come out. There are rivets that hold the stainless cover over the boiler unit that have to be drilled out to remove the cover.

I have a slightly different opinion about a leak at the exhaust opening based upon AH’s that I have seen leak there. There is a rather large opening welded into the bottom of the tank to allow the diesel exhaust pipe to exit. The failures I have seen in the tank corrode just outside the weld zone on the bottom of the boiler vessel. You can confirm this with the paper towel trick. Put some inside the exhaust opening and some outside the opening. That will clue you in on the location of the leak.

Where are you located?

IRVSOUTH · 12-07-2022, 05:03 PM

Quote:

Originally Posted by RichardE

So……… water or coolant tends not to run uphill.

Let’s take advantage of physics in helping you find the leak BEFORE you go to the work of tearing out the box.

Take some white paper towels and stuff them in and around the filler neck as far into the opening as you can. The green or red coolant will stain them if it is leaking there. You will have to run the unit to cause the leak. The filler neck can be repaired in place although it’s not for the faint of heart. It fails where the lip for the cap is brazed to the fill pipe. You take a MAPP torch and heat it until the solder melts and you pull the lip off. The kit then places a silicone coolant hose with clamp over the fill pipe. The coolant hose is short and has a lip for the cap on the other end. Sort of ingenious for a fix that doesn’t require removal of the unit.

If it is anything else, the unit HAS to come out. There are rivets that hold the stainless cover over the boiler unit that have to be drilled out to remove the cover.

I have a slightly different opinion about a leak at the exhaust opening based upon AH’s that I have seen leak there. There is a rather large opening welded into the bottom of the tank to allow the diesel exhaust pipe to exit. The failures I have seen in the tank corrode just outside the weld zone on the bottom of the boiler vessel. You can confirm this with the paper towel trick. Put some inside the exhaust opening and some outside the opening. That will clue you in on the location of the leak.

Where are you located?

I'm in Naples Florida at this time. Down for the winter so it's not an urgent issue but it needs fixing. From what you describe I would assume it's not the neck leaking but the tank. Since I can pressurize the tank the leak must be below the neck line. I will re-pressurize the tank and keep pressure on it until it stops leaking then I can measure the depth of fluid in the tank vs the depth of the tank and that should give me a good idea as to where the leak is. I'm thinking it will be a re and re not a simple fix. Thanks for all your help Richard and everyone else who dropped in on the thread! Have a great night!

shootist · 12-07-2022, 05:25 PM

Quote:

Originally Posted by IRVSOUTH

I'm in Naples Florida at this time. Down for the winter so it's not an urgent issue but it needs fixing. From what you describe I would assume it's not the neck leaking but the tank. Since I can pressurize the tank the leak must be below the neck line. I will re-pressurize the tank and keep pressure on it until it stops leaking then I can measure the depth of fluid in the tank vs the depth of the tank and that should give me a good idea as to where the leak is. I'm thinking it will be a re and re not a simple fix. Thanks for all your help Richard and everyone else who dropped in on the thread! Have a great night!

No you can't run it without it full of boiler fluid. It has a float switch to keep it from being burnt up if the fluid runs low. Do what was suggested. If it leaks up top it will still drip out the bottom.

153stars · 12-08-2022, 09:31 AM

You could draw enough fluid out to just below the cap neck and pressurized the system with pump kit. No leaks of fluid then good chance it's the neck. Some leaks will get worse at higher temp due to dissimilar metal expansion.
You could partially dismantle a your old cap by removing return button valve. Then use the return hose with hose barb and air fitting hose barb at less than 15psi. The upper gasket may leak by some. Of course you need a new cap.