AquaHot leak at the cap.

[distaff]

I have also posted this to Roger Berke's forum, before I get a bunch of suggestions I do that, but folks here often have very similar experiences to learn from.

Symptoms -

• Last February I noticed the unit was leaking boiler fluid from the cap. Removed the cap, refilled, replaced the cap, problem seemed solved (fluid level in the overflow was rising and falling with heat cycles) but I parked the coach shortly thereafter.
• This fall had a friend stay in the coach for a few weeks, using the AH. After she moved into the house I noticed the overflow was empty.
• I filled the overflow tank to the cold fill line, and added about a jug of fluid to the boiler (about 3 inches from the top of the neck) and installed a new cap (the old one was pretty new).
• Fired the unit and let it cycle, saw a drip come off the neck at the cap and steam from the top of the cap.
• Very difficult to say for sure due to the location, but it seems the leak is through the cap and not lower, will let it cool to examine it again, but I also note that after coming up to temp, there was no additional fluid in the overflow.
• Is it possible that the overflow line is blocked and causing pressure to escape around the cap?

Really hoping it isn't failure of the neck as that is a difficult repair, but hoping doesn't fix things. My next step is to let it cool, remove the cap, check the fluid level, remove the overflow hose, check the neck and overflow outlet, and test it again with a hose to a jug on the ground.

[Outbound]

When it cools down does fluid level in over flow tank return to filled level or stay empty.

[distaff]

So far the level in the overflow is not changing, but I may have to let it cool off longer (I will turn on the heat in the coach to draw out some heat). I will report back in a while.

[96 Wideglide]

This is the reason I've avoided touching my cap.

I regularly watch the level in the overflow tank to make sure it's raising when hot, and lowering to the same point when cool.

[distaff]

Ran the heat for 25 minutes and the level didn't change. The boiler fluid should have cooled down enough to pull some back from the reservoir.

[distaff]

Mr. Berke is suggesting his solution to the problem (assuming it is a damaged neck):

https://www.parts.rvhydronicheaterre...r-Neck-Kit.htm

Now, at $350 I imagine there is excellent profit margin in this part, but given the alternative of removing the unit I may pull the pin on this. Need to do a bit more exploring to make sure I have the problem this solves.

[96 Wideglide]

Have you cut an inch or so off the overflow hose, and re-installed?

[distaff]

Originally Posted by 96 Wideglide

Have you cut an inch or so off the overflow hose, and re-installed?

That part I'm not clear on. I asked how it installs and his answer was "instructions come in the package". I will examine my system tomorrow and will ask the question again. I would prefer to understand how to install it before I fork over the money.

[FLYING BUTCH]

I had same problem. Found a small leak in the hose that went into the radiator cap. Replaced small section of hose and stopped problem. Good luck

[Windecker]

Absolutely worth trimming the last inch off and reconnecting. A bit of a fight to get the old one off (maybe). Also, make sure the tiny little hose clamp holding the hose on is not bent up or whomped (technical term LOL) on so hard it cuts through the hose.

Also, they recommend putting on a new higher pressure cap. I think the original is around 7 PSI and the replacement is around 12 PSI. Of course, make sure the sealing surface just inside the filler neck is clean an free of crud that might prevent the cap from sealing.

Lastly, these are known to leak at the plastic drain fitting out of the bottom of the tank, just to the right of the burner assembly (shown below).

In my case, only leaked with up to full temp and slowly leaked more over time (heat cycles and months...). Later model units than mine (2005) had a brass drain fitting and not plastic. Not sure when they swapped to brass? Quite easy to tell the difference though.

Good luck!
Windecker

Originally Posted by FLYING BUTCH

I had same problem. Found a small leak in the hose that went into the radiator cap. Replaced small section of hose and stopped problem. Good luck

[distaff]

Originally Posted by 96 Wideglide

Have you cut an inch or so off the overflow hose, and re-installed?

Didn't read this correctly, I'm going to try putting a new section of hose on that flows out the side to a jug, and see that the tube at the neck is not blocked.

[96 Wideglide]

Certainly worth a try!

There was a recent thread where a member was sure it was either the cap, or neck, and it ended up being the hose split. It would only leak a little when the boiler was up to full temp, on diesel.

[distaff]

After further consideration, and following Roger Berke's directions, I pulled off the radiator neck. It was not easy to get at, and I had to use some wood shims to wedge the hoses up out of the way to clear some space to work.

After struggling with a pipe wrench, I did use a little heat to soften the solder - to protect the hose I took a small glass cutting board and wrapped it in aluminium foil and wedged it it between the neck and the hoses. I don't think that this would provide enough protection to attempt soldering a new neck in place, so I will go with an approach that doesn't require soldering.

Then with a couple of pairs of channel lock pliers I was able wrench it out. Pictures of the exposed pipe, removed neck, and tools below, sadly this site and Apple are not compatible and all my images post upside down. Please stand on your head while viewing.

I am considering finding an aluminum weldable filler neck. My neighbour has a small machine shop in his garage and we will weld it to a short bit of 1.5 inch diameter aluminium tube, with a short section of the tube machined down so it will slide inside the pipe for stability, then will attach the two with a bit of hose. More pictures when we have the parts ready to be assembled.

[shootist]

That's not an easy place to solder but more than doable. I have worked on mine enough to know it would take some time with fiberglass welding blankets to protect everything.