Aqua Hot Questions...

[sloman2001]

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)

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

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?

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?

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.

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

[ct1964ups]

paulcardoza wrote:
Chuck,

If you are going to leave the Aqua-Hot running (either electric or diesel), you will be fine with what you did. HOWEVER, if you shut it down and it freezes, you'll be in big trouble, without proper winterization with the pink stuff. If the internal coils freeze and burst, which will happen quite easily if allowed to freeze, the unit CANNOT be repaired. You'll be looking at a $10,000 bill for a new unit.

We also have it in an enclosed insulated garage that is attached to the house....2 walls use the house walls.....and one wall is along another 40 ft garage.....so only the door really faces the outside.....but neither garage is heated.....Chuck

[dougrainer]

NOT running antifreeze thru the hot water coils is a bad idea if you will depend on leaving the unit plugged in and using the 120 or diesel to keep it hot. What happens if you have a major storm and you lose power for a few days??? The system shuts down and then will slowly get cold and then freeze. We just had this type storm in the DFW area of Texas and 10's of thousands were without power for up to 4 days and the temps we had would have frozen the water coil in a Aqua Hot unit. Doug

[paulcardoza]

Chuck,

If you are going to leave the Aqua-Hot running (either electric or diesel), you will be fine with what you did. HOWEVER, if you shut it down and it freezes, you'll be in big trouble, without proper winterization with the pink stuff. If the internal coils freeze and burst, which will happen quite easily if allowed to freeze, the unit CANNOT be repaired. You'll be looking at a $10,000 bill for a new unit.

[ct1964ups]

Hjudge49 wrote:
Chuck, you can still use the Aqua Hot for heat. The boiler is still full of fluid, and the fact that the domestic water coil is empty (or partialy empty) will not hurt it. It would actually be better for you to keep it turned on, since opening the low point drains doesn't really get all the water out of the coils. I never winterize my coach because I live in Florida, but when it even thinks about freezing, I keep mine turned on electric to make sure it doesn't freeze. If it does, it's a replace, not repair situtation.

Hey guys...both of you ..for the quick answer.....Chuck

[smlranger]

ct1964ups wrote:
it is a great system and this is what I did so far....
I drained all the domestic water from the lines....I disconnected the water lines from the pump....and opened both low point drains...BUT I DID NOT RUN THE ANTI FREEZE THRU THE LINES
now my question...CAN I STILL RUN THE AQUA HOT SYSTEM FOR HEAT USING EITHER THE DIESEL OR THE ELECT.....????
Thanks..Chuck

When I asked that question of Roger Burke on the Aqua Hot forum, he said yes. The Aqua Hot system is filled with a boiler coolant and that is what provides the heat to your heat exchangers in the coach. So, even if you 'winterized' you can still use the AH for heat.

Regarding Winterization, both Aqua Hot and Roger Burke strongly advise not to rely on just draining the domestic water and using air to blow out the water lines. The coiled domestic water lines in the Aqua Hot need to be winterized by pumping RV antifreeze (the pink stuff) through the system. Merely blowing out the water lines may leave enough water in the Aqua Hot coils for freezing and bursting. If that occurs, the repair is very expensive.

[Hjudge49]

Chuck, you can still use the Aqua Hot for heat. The boiler is still full of fluid, and the fact that the domestic water coil is empty (or partialy empty) will not hurt it. It would actually be better for you to keep it turned on, since opening the low point drains doesn't really get all the water out of the coils. I never winterize my coach because I live in Florida, but when it even thinks about freezing, I keep mine turned on electric to make sure it doesn't freeze. If it does, it's a replace, not repair situtation.

[ct1964ups]

it is a great system and this is what I did so far....
I drained all the domestic water from the lines....I disconnected the water lines from the pump....and opened both low point drains...BUT I DID NOT RUN THE ANTI FREEZE THRU THE LINES
now my question...CAN I STILL RUN THE AQUA HOT SYSTEM FOR HEAT USING EITHER THE DIESEL OR THE ELECT.....????
Thanks..Chuck

[zmotorsports]

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.

[dougrainer]

You have been given answers to most of your questions. I will answer the 2 that were not answered.

1. You MUST ask the dealer or OEM about specific bay heating concerns. ALL RV's are different and only they can answer your question.
2. The reason you cannot blow out a Aqua Hot type system is, the Hot Water copper tubes are extremely small in diameter and are coiled thru the Heater tank fluid. This is how you can get continuous Hot Water. Blowing out this coil system, according to Aqua Hot (their manual states this also) you cannot get all the moisture out from blowing out and this mist of water can run and form a small water droplets and THAT when freezing can burst the copper line. Aqua Hot does NOT sell that part and the only thing to do is either buy a new complete unit or ship the unit back to Aqua Hot for rebuild which still costs thousands of dollars. If you are using the unit and have the 120 element or the Diesel unit on, the unit cannot freeze. What you do to winterize is, blow out the complete RV and once done, you run RV antifreeze thru the water pump until the pink comes out the Hot water low point drain. That means the copper loop has RV antifreeze in it. Doug

[Golden_HVAC]

If you have both the burner and electric on, I think the electric trys to keep it at 180F while the burner comes on once the water in the reservoir is below 150F until it reaches 170F, then it goes off until cooled by use (either domestic hot water or running a hot water coil to heat the coach).

The hot water tank being in the basement should help keep the basement warm.

Like said above, you might have 1 or 2 electric heating elements. One is normally rated at 1,500 watts 120 volts, the other might be rated at 3,500 at 240 volts. But it can change - depending on your model number.

Is it cheaper to run on diesel or pay for electric? Here in Portland OR, the hydroelectric power is pretty low cost, $0.10 per KW. 1 gallon of propane is 95,000 Btu's and in a LP heater will produce about 80,000 Btu's of heat, or what would take 22 KW in a electric heater. Diesel is about 135,000 Btu's per gallon, and can produce about 105,000 Btu's per gallon burned, given some heat goes out the flue. This is equal to about 32 KW. So it would cost $3.20 to offset one gallon of diesel in this area, more than $4.50 in Southern California with their higher $0.16 per KW power. For me, it is less expensive to run electric heat $2.20 than to buy propane. Diesel costs would be about equal up here in Portland.

Like stated above, if it gets below 30F, then leave the aqua hot on, it will not freeze. To save fuel, run the electric if at home, or a campground, but run it on diesel if you need to - if on battery power. You will need something to recharge the battery (solar or plug it in) if it is parked in a driveway or something.

Fred.

[sdianel_-acct_c]

We have a 2004 Country Coach Allure with Hydro Hot, the smaller version of the Aqua Hot. We have camped for 5 days in 17 degree icy snowy weather without winterizing the coach. Of course you should winterize if you are storing it and not using it. From the manual: "The Aqua-Hot's Domestic Hot Water Heating System must be completely drained of domestic water any time the heater is STORED where freezing temperatures may be experienced.
We have never winterized our coach as we continuously use it.
In the winter we turn on the electric and diesel switches per the owner's manual recommendations (unless we're in a park where we pay extra for electric) then we only use the diesel switch. We have a heat exchanger in the service bay that prevents freezing of the fresh water tank and water lines within the service bay. We fill our fresh water tank and disconnect the water line from the coach if the temperature is going to be below freezing for more than 2 hours. Our Hydro Hot provides "continuous" hot water very quickly. Note: on our coach the demand for hot water overrides the demand for heat temporarily. We never notice this feature because we don't use that much water due to grey water holding tank size. We don't worry about what temperature electric vs diesel. The diesel knows when to kick in. We just leave both switches on. Diesel is the primary heating source for hot water and furnace in low temps and high demand. Electric is a secondary source for higher ambient temps and low demand. We love our Hydro Hot (Aqua Hot). Here is a good website for Hydronic Heater Repair with some photos and info about Aqua Hots. Roger Berke is a great resource.

[Ivylog]

When stored outside I never winterized anything... just left the single electric element on and set the Tstats as low as they would go. This was enough heat to keep everything warm enough even when it was in the teens outside.

[gsander1]

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)

You never need to winterize if you are going to leave the system hot.

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

Every coach I've had with hydronic heat has had a heat exchanger in the water bay. You should ask the seller.

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?

Because the domestic hot water is produced via a coil in the AH. Coils of copper tubing don't blow out well and are destroyed by freezing water.

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?

No

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.

The answer is dependent on the size and insulation quality of the coach. Remember, the heating coil is only 12.6 amps. The same size as a small space heater. You wouldn't expect to heat a large, four slide coach with one space heater on low. So, maybe down to 45 degrees or so but you won't get much domestic hot water without the diesel burner.

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

[Mr_Mark1]

Tom,

Depending on which Aqua-Hot system that's in the coach that you are considering, it might have one electric element or two. Ours has two (110 and HI) and it will make the water scalding hot!

We have never winterized as we stay in milder climates. The whole purpose of the Aqua-Hot is to use it when it's cold. The engine will circulate the antifreeze through-out the system so you will have very hot water when you arrive at your destination.

You can use the heating system when you are driving down the road without the diesel running because the engine is heating the antifreeze.

If you are using the Aqua-Hot, it should heat the water bay area also so no worries about freezing the pipes. You will love the Aqua-Hot system.

MM.