Aqua Hot Questions...

sloman2001 wrote:
for a MH "wanna be".

We are considering a coach with the Aqua Hot system (I have read the operating manual) and are trying to find out a little more about it, so thank you in advance for any responses. Without laying out a litany of questions, here are 5 questions about the Aqua Hot system I’m seeking clarification on.

Can you use the AH hot water system when camping in sub 32 degree conditions (maybe 25 degrees), or must you always winterize if it is going to get below freezing? We often camp in colder weather, so I just want to know if I need to winterize at the slightest chance of 32 and below. (not asking about the coach heating, but the water heating system)
Yes, the Aqua-Hot or hyrdonic heating system is extremely well suited for cold temperatures. It was on our "must have" list when we were shopping because we used all of our motorhomes for snowmobiling each winter. If you do not run the system you will need to winterize the domestic water side of the boiler but no change with the glycol portion of the system is necessary when winterizing.


Generally, what constitutes the bay heating system (maybe coach specific)? Do I need to ask the particular dealer?

The bay heating system is a heat exchanger with a fan that circulates the heated glycol through the exchanger and the fan pushes that heated air out into the storage/service/tank bay.

To winterize, I have read you cannot merely blow out the lines, but you must use anti-freeze. I am just curious as to why?

For winterizing you will want to use the antifreeze method as there is approx. 150' of copper tubing that makes up the water heater portion of the system. This tubing is either inside of the boiler tank or on the exterior (depending on manufacturing date) where the exchange of heat takes place. With all of this tubing it is quite acceptible to see where water/moisture could condense and move into a low point in the tubing even after using compressed air to blow the system out. This could then freeze, rupture and cause a major expense to replace the boiler assembly/unit.

If you are going to be driving through conditions below 32 degree’s and are using the engine to heat the rig, do you still need to winterize your lines?

When driving in cold temperatures, generally the engine heat is enough to adequately heat the glycol for the system. However, I just leave the diesel switch in the "ON" position. This way IF the system drops below the lower temperature T-stat's setting the diesel burner will kick on the keep the glycol temperature at the set point. Very seldom does the diesel burner come on when traveling but we have had it kick on a few times in slow traffic where the diesel engine is not creating as much heat. Some people think that it is not a good idea to keep the switch on when running down the road but if the engine is keeping everything the glycol up to temperature it simply will not call for the diesel burner to kick on.

We have pulled into rest areas and been sitting for 15+ minutes in sub-freezeing temperatures eating when the diesel burner will kick on. It is actually quite amazing how well the system holds heat. That will also depend on how well the coach is insulated though becuase if the heat exchangers are running more to keep the inside of the coach warm, this exchange of heat will call for the glycol to be heated more often.

For heating only (not for the continuous water supply) to what general outside temperature will Aqua Hot’s use of the 120 VAC burner be sufficient before the diesel burner kicks in or will electric alone provide enough heat? In reading the operating instructions, it sounds like the electric element alone will heat the anti-freeze solution for heating. But it also sounds like you need the diesel burner, so I am just a little confused. Any clarification here would be helpful.

This to a great extent will depend on whether you get the system with one electric element or two elements. Our system has the single electric element and I just leave both the diesel switch and the electric switch on when camping at a park with power. The electric will work adequately and provide plenty of hot water during the summer months and in the cooler spring or fall months (temperatures in the high 30's/low 40's at night) the only time the diesel burner will kick on is when the wife and I are showering in the morning, otherwise the single electric element will work fine. Much colder than that and the diesel burner will kick in along with the electric element more frequently.

Maybe these sound a little dumb, so thanks for your patience. Thanks again for your time!
Tom

No problem Tom. There is a lot of controversy over the hydronic heating system among many of the RV forums, people either love them or hate them. Generally the ones that hate them are those who don't have them. Maybe even some people tell themselves that they love them because they have to justify the money they spent to get it in their coach.

I had some experience working on them on my cousins and aunt/uncles coaches before we purchased ours so I was fortunate enough to have a good idea of what I was getting into prior to purchasing our current coach.

Even though we had some issues with ours when we first purchased the coach (my guess would be the original owners did not understand the system nor want to pay to have it repaired) we would not own another coach without the Aqua-Hot system.

Mike.