Older Hydro Hot antifreeze tank leaks.

[Roland DuBree]

I have had some leaks in my 2001 Contessa coach Hydro Hot tank.  I managed to get most stopped at least where I see the fluid at the bottom of the tank on the tray by adding radiator stop leak pellets.  However, the antifreeze still disappears some place I cannot see. I went to the internet and Googled to "hydrohot (Aquahot) leaks" which really sent me to "Hydrohot (aquahot) leaks on Country Coach forum" This led me to a post about leaks and the second answer post from "Scott on June 9, 2011" gave an explaination of how he stopped the leaks converting his anti freeze tank to an NON-Pressurized tank.  He converted by simple removing the very bottom rubber gasket from the radiator cap.  The top gasket remains to seal the system, but the bottom is used to create the pressure at the 13 psi. With gasket removed, no pressure and fluid just flows out and in of the antifreeze tank to the overflow tank as the antifreeze get hot and cold.  I have not tried this yet but I tried to get Aquahot support to comment on it. They refuse to say yes or no. I presume for legal purposes.  But I found out all newer units now built are NON-PRESSURUZED antifreeze tanks that work as Scott suggests in the forum. You Beaver owners just might want to look at his post and try what he suggests.  some where down the road I am going to try it too when the overflow tank is empty again!

[Roland DuBree]

Wow, on 5/8/2017 the above had 105 views but not one reply!  I had Hoped someone who had read it might have tried it and let me know what they thought of it?

[Gerald Farris]

Roland,
There are a few problems that may develop if you use your Aqua Hot unpressurized. It was originally designed as a pressurized system because it operates so close to the boiling point that the coolant solution could boil where it contacts the burner housing causing uneven heat transfer, and vapor bubbles in the solution that could cause air locks in the system because the coolant pumps will not pump air well, liquid only. This is especially more prone to happen if your control thermostat is operating slightly above the design set point. Therefore, if you monitor the system closely to ensure that you are getting no bubbles in the coolant that is leaving the Aqua Hot unit as it travels to the expansion tank, especially at higher altitudes, an unpressurized system should work well.

If you can find a 7 PSI cap to fit you Aqua Hot unit (some Aqua Hot units have an nonstandard cap), this may be an acceptable alternative to an unpressurized system.   

Gerald

[Roland DuBree]

Gerald, I wonder how Aqua Hot avoids the bubbles and things you mention in your post in the newer units that supposedly have a non-pressurized antifreeze tank?

[Roland DuBree]

My Hydro Hot unit has the large size radiator cap.  Bought a new one a couple years ago for about $100.00 and could only find it with a Hydro Hot dealer.  Never could find one any place else. Now wish I had kept the old to try the gasket removal.  The likelihood of finding a 7.5# cap instead of the 17# in that size is probably impossible.  Anyone have an old one they don't want send it to me!!