Aqua Hot On The Road

[Cat320]

I am still trying to figure how this thing works on the road. If we are driving, does the AH work for coach heating without turning on the diesel burner? Do we just scroll through the thermostat settings, select "heat" and it works, or do we need to fire up the burner like when do when camped?

[38 Special]

I leave the deisel burner off and turn the thermostat to furnace. Works good here in the south. If severe cold, may need more than the engine will produce.

[texnet]

Not sure about your coach and setup but here is how mine works.

Heat = Heat pumps from roof air conditioning/heat pump turned on
Furnance = Aqua Hot heat enabled

Our coach is setup so the engine cooling system is circulated through the Aqua Hot system and thus provides heat to the coach, but at a lower rate of btu. If we need more heat we turn on the Aqua Hot switch and the diesel flame lights up as needed.

[ottffss]

Originally Posted by Cat320

..If we are driving, does the AH work for coach heating without turning on the diesel burner? ....

Yes. In all probablilty your rig is set up this way. But...

Originally Posted by 38 Special

I leave the deisel burner off and turn the thermostat to furnace. Works good here in the south. If severe cold, may need more than the engine will produce.

As 38 said, it is possible to exceed the ability for the engine to heat the AH enough to provide heat. Typically this can happen if driving in single digit temps and/or you want it overtly tropical inside. Also note that if you use domestic hot water in this manner it may take quite a while for the engine to reheat the AH enough to turn on the heaters again.

If you are not getting enough heat/hot-water without the diesel burner on while driving then just turn on the diesel burner and all is good again.

Try it and see! (Give the engine time to heat up the AH enough to get heat, or just run the diesel when you first start in order to heat the AH up and then turn off the diesel and see how far you get.)

[hooverbill]

When camped and I am using electric only, and it's cold, the coach will not warm up enough to be comfortable, and the burner must be turned on. Same when driving and using engine heat, if it's too cold, as noted above, you must turn on the burner.

[Dave78Chief]

The Aqua-Hot FAQ 10 (http://www.aqua-hot.com/esource/ecom/esource/default/FAQs.aspx) says to leave the diesel burner ON while driving to ensure the boiler water temperature is high enough to keep the coach warm.

The closed engine pre-heat system will circulate water through the boiler while the engine is running. The Aqua-Hot is in effect acting a like a 2nd engine radiator during this time as this is the same engine coolant water being circulated through the engine radiator. The engine heated water typically runs in the region of 180 to 215 degrees and is used to heat the Aqua-Hot boiler water. The Diesel Burner thermostat in the Aqua-Hot boiler typically operates in the range of 158 to 190 degrees. If the Aqua-Hot boiler is kept hot enough by the engine pre-heat water, then the Aqua-Hot boiler thermostat will not light off the diesel burner. If, do to Aqua-Hot system loads (ie outside temps real low), the engine pre-heat water is not able to keep the boiler temp up high enough, the Aqua-Hot boiler thermostat will light off the diesel burner in order to provide the extra heat needed to bring the boiler temp back into it's operating range. So, the Aqua-Hot boiler switch can be ON but it will not light the diesel burner if the engine pre-heat water keeps the boiler at operating range.

The floor registers and associated pumps are controlled by seperate Thermostats. Coach installations that have dual Duo-Therm A/Cs typically use a 4 or 5 button CCC unit. The Aqua-Hot heat exchangers are also controlled by the Duo Therm CCC system. For a 2 zone Duo Therm system, when set for furnace, the thermostat in the main CCC unit controls temps in the front half of the rig and a thermostat associated with the rear AC unit controls temps in the rear of the coach. Each AC unit sends a control signal to the Aqua-Hot (reffered to as zones on Aqua-Hot) as needed based on the seperate theromostat settings (zone set points of Duo-Therm CCC). These are just 12VDC On/Off signals. When the zone control signal is ON, the associated Aqua-Hot zone pump starts circulating water for the zone and the zone heat exchanger fan is turned ON.

While I used a Duo-Therm system to explain heat exchanger operation, there is no reason seperate thermostats (Front, Rear, storage Bays, bathroom, etc.) cannot be used to control Aqua-Hot zones. Aqua-hot simply needs some form of zone control thermostat to control heat exchanger operation.

Aqua-Hot (formally Hydro-Hot) Operators, Installation, Service, and Parts manuals are located here: Aqua-Hot Heating Systems Inc.

To recap,

Just remember the heat exchangers distributed around the coach are feed from closed loop systems like an old radiator system in a house. The fan in each heat exchanger and the associated water circulating pump used to move water in the zone system is controlled by a standard room thermostat.

The boiler can be heated by the diesel burner, and electric element (shore power or generator), or engine preheat water. Both diesel burner and electric element are controled by a boiler thermostat. Engine pre-heat water is what ever temp the engine radiator water is at.

Dave