We're going to talk about the different kinds of Boiler antifreezes that are used in our Aqua-Hot's & Our Hydro-Hot's. There is the Green type (Ethylene glycol) and the newer Pink type (propylene glycol).
Aqua-Hot with serial # 03-725 or Greater, or Hydro-Hot serial # 03-586 or greater use the pink antifreeze (Propylene glycol), All Aqua-Hot's with the serial # 03-725 or (Lower) or Hydro-Hot serial # 03-586 or (Lower) use the older automotive antifreeze type (Ethylene glycol) which is usually Green .
The difference is in 2003 they put the domestic hot water coils inside the boiler tank and before that the earlier Aqua-Hot's and Hydro-Hot's they bonded the domestic hot water coils on the outside of the boiler tanks . So the reason is if you use the (Ethylene glycol) Green in the newer style , coils inside the boiler tank if you develop a leak in the domestic heating coils you can get antifreeze in your drinking water or ice cubes or any other water in your coach , If you drink (Ethylene glycol) Green You DIE!!!! The older style Aqua-Hot's serial # 03-725 or lower ,or Hydro-Hot's serial # 03-586 or lower with the domestic water heating coils on the outside and you develop a leak it just leaks out , Bad thing you got problems.
Be careful what type of (Pink) antifreeze you use, there is a difference, there is boiler antifreeze and there is the type you put in your water pipes to winterize your coach, they are both (Pink) and both safe if drank. The difference is the one antifreeze for winterizing does not do anything for boiling point and it usually is bought at most stores that sells R.V. supplies and runs about $3.00 to $5.00 a gallon and the Boiler antifreeze is harder to get and it usually is about $25.00 a gallon, And Roger or Aqua-Hot or any of us authorized Aqua-Hot service center carries that product.
So if you have the newer style (Coils on inside) and you notice your water is a little pink check it out, But you won't die if you drink it. Or if you have an old style (Coils on Outside) you can use either one. Be Safe out there.
Thanks for that info Art. Gonna bookmark this post!