[Rudy]

Aqua-Hot is a closed system, they do not mix.

[Archived]

Thanks Tom. Glad of that.

[Bill]

Steve,

The Aqua Hot heater has a engine coolant copper coil wrapped around the outside of the heater coolant tank that is immersed in a heat transfer mastic. The hot coolant in the tank heats the engine coolant in that coil. Either the engine coolant pump or the AH engine preheat pump circulates engine coolant from one end of the engine through the heater coil and back to the other end of the engine. Leave the AH engine preheat pump off unless heating the engine prior to starting in cold conditions.

The main engine heats the AH heater coolant tank going down the road all of the time the main engine is running. The AH preheat pump heats the engine before starting in cold conditions. As shared earlier, the two coolants never mix.

Hope this helps you.

---

2005 XL Thompson Coach

Rarely tow anything behind us.

Sold: 1993 Liberty that we loved for 12 years.

[Corey]

Neither system should be rusty or have residue.

Coolants are designed to prevent corrosion and if they are maintained you should not see rust.

[Archived]

Rudy,

You might want to recheck that. I have had the occasion to completely rebuild my AquaHot and i think you will find the copper coil, set in mastic, on the outside of the boiler contains potable water.

There is a loop head exchanger inside the boiler through which engine coollant flows. When the engine is running the flow of engine coolant through that loop heats the boiler coolant. When the engine is not running and you want to warm it up on a cold night, you can run the AH pump for engine heat and it will circulate through the same internal heat exchanger and heat the coolant for the engine, thus heating the engine.

Both coolant systems ( engine and AH ) are totally isolated unless there is some failure of the heat exchanger inside the boiler.

Russ

[glen]

Russ,

Just goes to show you what I know. I thought on heaters not having an electronic control board, that both fresh water and engine loops where on the outside. But your first hand experience trumps here. The operation is still the same.

The newer heaters with electronic control boards have both coils inside of the tank. This has brought about the use of GRAS (Generally Recognized As Safe) boiler fluid so a leak in the fresh water coil can not hurt you.

Thank you for correcting my info.

[Greg]

Good info Russ. Thanks to all . This helps as I undertake replacement of tank and copper tubing.

[Peter]

Is there any problem running the “warm-up” recirc pump while driving? It seems that just relying on the engine’s water pump to recirculate the coolant through the AquaHot system does not provide as much heat up front as when I augment that flow with the warm-up switch on.

Will this cause any problems??? Rudy?

[Tim]

Steve,

I have replaced my tank and wrapped it in copper. Job completeld a year and a half ago or so. No problems since. I found a source for the mastic heat transfer medium. If I can be of any help answering questions or supplying pictures just shot me an email.

I have a home in Maryville too! In the Keys for the winter and on Tellico Lake for the summers normally.

RussWhite at Earthlink dot net

[John]

Russ,

Running the engine preheat pump while the main engine is running should not be a problem. You are experiencing a noticable increase in heat transfer which is most likely an increase in flow rate of engine coolant through the preheat coil.

Now if the engine coolant lines were to be connected backwards, then the two pumps would work aganist one another. But in your case, the noticable increase in heat says yours are in sync with one another.

To the folks that have successfully repaired a split fresh water loop in their heaters, please accept my congratulations and my admiration of you expertise. This is above my pay grade and a fine accomplishment. Bravo to you.