Hydro-Hot Tank Leak

[Jack W Hannah]

The tank in my Hydro-Hot system has developed a significant leak. Stop Leak has been suggested as a possible fix. Does anyone have any experience with this situation and possible fix short of complete unit replacement?

Thank you,

Jack Hannah

[Eric Maclean]

Jack
Two and a half years ago I bought my coach it has an Aquahot unit installed that had been bypassed so I set out to get it working
First after repairing fuel leak issues and getting the burner to work .
It became apparent very quickly it had problems the first thing was the tank bottom had a series of pin holes eaten through so it would constantly leak antifreeze when filled .
The second problem was I think related to the first , I think the system had been run low on antifreeze and had cracked the burner chamber causing it to leak antifreeze into the chamber when the burner was running and creating a large cloud of white smoke at the tail pipe.
After contacting Aqua hot and discovering that a new units price was outrages and a new tank was $9500 I decided I could do a lot of welding for that price.
The third problem was the domestic hot water coil had been frozen and was destroyed.
What I ended up doing is removing the unit and completely rebuilding it as follows
1) I removed the domestic hot water coil from the outside of the tank.
2)  cut the bad section out of the bottom of the tank.
3) cut the burner combustion chamber out of the tank end plate.
4) located a wabosto 2010 coolant heater and cut the outer shell off the heat exchanger to ready the combustion chamber for installation. ( It was interesting to see that this is exactly what Aqua hot had done to build it in the first place.
5) welded the combustion chamber back into the tank end plate.
6) fabricate and replace tank bottom.
7) rap the tank with 160 feet of 1/2 copper tubing .
(the tubing came in 100 foot rolls so used it all 200 feet and as a result have better hot water production.)
incase the copper tubing in heat transfer cement
9) reassemble the unit into it's enclosure
10) reinstall into the coach

The completed unit looks and works just like a new one
I made all my welds with a mig welder and the welds have to be water tight
The system has worked flawlessly now for two years.
Hope this helps
Eric
Jack
With your unit for a temp fix you might drain and dry out the tank and try to pour an epoxy into the tank to seal the bottom .
Or if you can get to the bottom of the tank ( I don't think you can in the unclosed ) you might be able to use a screws and rubber washer to seal the hole the real problem is the tank is rusting out and the rest of the bottom is probably not far behind.
You could try stop leak but I'd try water glass instead you should be able to get it from a good old time pharmacy.
Good luck
Eric

[Neal E Weinmann]

Is it leaking water or is it leaking coolant? Mine developed a water leak at the connections in the rear of the unit. I replaced all the compression washers and the leak was gone.

If it’s a coolant leak, check the simple things first - the overflow hose from the coolant tank neck to the plastic expansion tank and the plastic expansion tank itself.

[Eric Maclean]

Jack
As Neal suggested find the leak first .
Some people here on the forum have had the filler neck come loose in the tank creating ba leak where the filler enters the tank.
Eric

[David T. Richelderfer]

Several years ago our AquaHot developed a small leak that continued to get worse over a few months.  Antifreeze was leaking out of the aluminum shell and running on the floor until it found a hole where it dripped on the ground.  I thought the radiator cap might have outlived its useful life so replaced it.  In the process of removing the radiator cap, I broke the soldered-on radiator-cap collar off the top of the interior tank.  But this was not the leak I was looking for but now I had two problems.  I ended up having the AquaHot annualed by Mike Flowerday in LaPine, OR.  Mike used JB Weld to affix the collar back on and it's been good since.  The leak I originally saw came from the 110v electric water heater coil.  The coil is a replaceable unit that screws into the interior tank and uses an O-ring for a seal.  The O-ring had started decomposing and was rapidly deteriorating causing the leak to lose more anti-freeze quite quickly.

You might find this thread an interesting read...   http://beaveramb.org/forum/index.php/topic,3069.msg29012.html#msg29012

[Eric Maclean]

Jack
Rebuilt units may be available from John Carrillo at heat my RV you can checkout his web site.
Eric

[Bill Sprague]

After about 10 years, our HydroHot was not working right.  A couple certified by AquaHot techs tried and failed to figure it out.  John Carrillo fixed it.  It was clear to me that he is among the best of the best in the AquaHot service and repair business.

[Jack W Hannah]

Thanks to all for your input; very much appreciated.  As suggested, I’ve already reached out to Heat My RV for their input.
Eric – Unfortunately, I have neither the skill level nor the facilities to attempt such an extensive repair/rebuild. Wish I did. About the extent of my capabilities is pouring something in the tank and hope it solves the problem. To that end, can you tell me a little bit more about Water Glass that I would get from a Pharmacy?

[Bill Lampkin]

Maybe see below:
https://www.drugtopics.com/view/opinion-liquid-glass

[Eric Maclean]

Thanks Bill for the description
As a young mechanic some 40 + years a go I learned from an old timer how to use water glass to seal water leaks in a cracked
 ( frozen) engine block.
There are other products used to seal leaking radiators and cooling system leaks one of my favorites was called Bars leak but it  when poured out of the can it has what looks like pellets of saw dust .
Most commercial stop leaks are the same and use a filler to help plug the hole the problem with the fillers is that they can plug the small openings in heater cores that's why I recommended water glass as it is a liquid .
I believe water glass is actually one of the active ingredients in most stop leak products.
Over the years I've seen everything from pepper to raw eggs used to stop rad leak's with success.
Most products should be poured into the system at operating temperature say 160 degrees or higher and allowed to circulate the water glass turns to a gel and solidify a when it exits the crack of hole and comes in contact with air.
Hope this helps Eric

[Jack W Hannah]

Bill & Eric,

Thanks again for the info. Very much appreciated.

Regards,