Talk to me about hydronic heating

[Ductape]

Good morning everyone. We're shopping for the next coach and the model we like has the option of either conventional furnace or hydronic heating. Those with experience with both, what are your thoughts?

We like to boondock a lot, and I like the idea of heating with diesel rather than propane.

I think the hydronic systems are quieter, is that correct?

I wonder about battery use as well, does a hydro system use more or less electrical power to run the boiler, pumps, and fans?

Thank you for sharing your knowledge. 🙂

[Mile_High]

tropical36 wrote:

Mile High wrote:
Believe me, there is nothing bullet proof about the LP furnace in an RV. Every winter on the forum you can read the complaints from folks that have board failures, thermostat problems, etc. Between the two type of systems, I don't think either has a reliability advantage.

So very true, but with these old systems, they pretty much all work independently of each other and the point, I was trying to make.
The best example is with my two separate forced air furnaces and the hot water tank, which have nothing to do with each other. Of course, they share the propane tank, but not like the tank is prone to failure with gadgets and moving parts to keep it operational.

I agree, it's a valid point. Our first trip out we had one furnace that wouldn't run and 1 AC down but we made out fine.

Turns out I had erased them from the thermostat and had to program them back in 🙂 Took some nice feedback from the forum to get me back up with all running.

[Bill_Satellite]

Mile High wrote:

Bill.Satellite wrote:

Mile High wrote:
For the MHs we looked at, in general the hydronic heated units had 150 gal diesel tanks whereas the others only 100 gal.

Are you comparing diesel vs. Propane fuel?

No-no, not really. Just pointing out that the manufacturer typically increased the diesel fuel tank size for units equipped with hydronic heating in case anyone was concerned about the heat eating into the chassis overall travel range.

Ah, thanks. I get it now.

[Executive45]

The AquaHot system is a pretty simple system. It's just difficult for this old guy to get to. I did climb in the lower bay with the technician and he showed me how it all worked and what needed to be done for simple repairs. Obviously I don't have and/or carry things to adjust the fuel pressure in the unit, but everything else is pretty simple if you have even minimal skills.....Dennis

[tropical36]

Mile High wrote:
Believe me, there is nothing bullet proof about the LP furnace in an RV. Every winter on the forum you can read the complaints from folks that have board failures, thermostat problems, etc. Between the two type of systems, I don't think either has a reliability advantage.

So very true, but with these old systems, they pretty much all work independently of each other and the point, I was trying to make.
The best example is with my two separate forced air furnaces and the hot water tank, which have nothing to do with each other. Of course, they share the propane tank, but not like the tank is prone to failure with gadgets and moving parts to keep it operational.

[Mile_High]

Believe me, there is nothing bullet proof about the LP furnace in an RV. Every winter on the forum you can read the complaints from folks that have board failures, thermostat problems, etc. Between the two type of systems, I don't think either has a reliability advantage.

[smlranger]

tropical36 wrote:

smlranger wrote:

tropical36 wrote:

Executive wrote:
While not the Hydronic system, we have it's brother, AquaHot. If it smokes, it needs servicing. It will smell a bit though. That said, our unit has separate blowers at each of the registers so it's very quiet when it's running. We leave ours on electric most of the time and only need to fire up the unit for showers as DW likes long hot showers in the morning. Heating the rig is just a humming sound. Wouldn't have another coach without it....Dennis

Question....How does all this work and let's say the AquaHot/Hydronic, system fails and whether or not you're boon docking or not, what do you do for hot water, heat, etc....and until you get it fixed?
I would guess the genset for space heaters, but how about the hot water and if I'm to understand this thing correctly, most everything is dependent upon it working, instead of having individual self contained appliances. I'm also assuming that the range is electric and needs the genset, correct?

If your Aqua Hot system failed completely, you would not have hot water or the ability to heat the coach beyond what you could do with electric heaters (generator or shore power) or overhead heat pumps.

The Aqua Hot has both electric heating element/s and the diesel burner. It seems that issues with the diesel burner (Webasto) are more common than any issue with the electric heating element. However, if the burner will not work, the electric element is limited in how much hot water or heat it can provide. But, you can still have some hot water with just the electric element.

Thanks for that and kind of what I thought, with the kind of specifics, I was looking for.
I'm getting old and still a little old school as well, so with our two overhead heat pumps, two independent forced air furnaces, elect/propane hot water and of course, portable on board space heaters, I feel that we're good to go, no matter. Still have the RV fridge, too, but just as soon not, with having a 2KW inverter.
Eventually these modern systems will be the only thing out there and pretty much bullet proof, as well. For right now, I am hearing about a lot of failures surrounding these systems, that don't sound like an easy fix, while out there on the road.

Frankly, I don't think you can count on any new 'systems' on modern RV's being bullet proof. In fact, it seems they fail more often as they get more complex. Not unlike home appliances these days. They are fully featured but don't have seem to be as reliable or durable as what many of us came to expect over the years. Just the way it is, IMO.

[tropical36]

smlranger wrote:

tropical36 wrote:

Executive wrote:
While not the Hydronic system, we have it's brother, AquaHot. If it smokes, it needs servicing. It will smell a bit though. That said, our unit has separate blowers at each of the registers so it's very quiet when it's running. We leave ours on electric most of the time and only need to fire up the unit for showers as DW likes long hot showers in the morning. Heating the rig is just a humming sound. Wouldn't have another coach without it....Dennis

Question....How does all this work and let's say the AquaHot/Hydronic, system fails and whether or not you're boon docking or not, what do you do for hot water, heat, etc....and until you get it fixed?
I would guess the genset for space heaters, but how about the hot water and if I'm to understand this thing correctly, most everything is dependent upon it working, instead of having individual self contained appliances. I'm also assuming that the range is electric and needs the genset, correct?

If your Aqua Hot system failed completely, you would not have hot water or the ability to heat the coach beyond what you could do with electric heaters (generator or shore power) or overhead heat pumps.

The Aqua Hot has both electric heating element/s and the diesel burner. It seems that issues with the diesel burner (Webasto) are more common than any issue with the electric heating element. However, if the burner will not work, the electric element is limited in how much hot water or heat it can provide. But, you can still have some hot water with just the electric element.

Thanks for that and kind of what I thought, with the kind of specifics, I was looking for.
I'm getting old and still a little old school as well, so with our two overhead heat pumps, two independent forced air furnaces, elect/propane hot water and of course, portable on board space heaters, I feel that we're good to go, no matter. Still have the RV fridge, too, but just as soon not, with having a 2KW inverter.
Eventually these modern systems will be the only thing out there and pretty much bullet proof, as well. For right now, I am hearing about a lot of failures surrounding these systems, that don't sound like an easy fix, while out there on the road.

[Mile_High]

Solo wrote:

I have no data to support this comment but, I suspect operating a hydronic Aqua-hot heat system with the diesel burner and then using batteries only to operate the pump and the small fans at each heat exchanger on our coach would require significantly less battery power than running a propane fired furnace like we've had in our other motorhomes.

I suspect you are correct - Both my SF25QW and SF20QW suburban furnaces draw 7.0 amp each. That 14.0 amps when both running. The furnaces are tough on battery draw.

[Mile_High]

Bill.Satellite wrote:

Mile High wrote:
For the MHs we looked at, in general the hydronic heated units had 150 gal diesel tanks whereas the others only 100 gal.

Are you comparing diesel vs. Propane fuel?

No-no, not really. Just pointing out that the manufacturer typically increased the diesel fuel tank size for units equipped with hydronic heating in case anyone was concerned about the heat eating into the chassis overall travel range.

[Solo]

Executive wrote:




The Aqua Hot has both electric heating element/s and the diesel burner. It seems that issues with the diesel burner (Webasto) are more common than any issue with the electric heating element. However, if the burner will not work, the electric element is limited in how much hot water or heat it can provide. But, you can still have some hot water with just the electric element.

To follow-up with with how well the electric side of our Aqua-hot system operates, admittedly, we are somewhat conservative water users but, the electric element provides all of our hot water and heat needs unless outside temperatures fall much below 45 deg F or so. If we have guests onboard, the diesel burner gets fired at times. However, for boondocking, remember the electric element is dependent upon shore power or genset whereas the diesel burner is not.

I have no data to support this comment but, I suspect operating a hydronic Aqua-hot heat system with the diesel burner and then using batteries only to operate the pump and the small fans at each heat exchanger on our coach would require significantly less battery power than running a propane fired furnace like we've had in our other motorhomes.

Smelly and noisy would not be my description of a properly operating Aqua-hot hydronic system.

[Bill_Satellite]

Mile High wrote:
For the MHs we looked at, in general the hydronic heated units had 150 gal diesel tanks whereas the others only 100 gal.

Are you comparing diesel vs. Propane fuel? If so, that would likely be 150 gal. of diesel VS. 100# or propane or something more like 25 gal.

[2gypsies1]

Our experience... they are noisy and smelly when parked next to them.

[smlranger]

tropical36 wrote:

Executive wrote:
While not the Hydronic system, we have it's brother, AquaHot. If it smokes, it needs servicing. It will smell a bit though. That said, our unit has separate blowers at each of the registers so it's very quiet when it's running. We leave ours on electric most of the time and only need to fire up the unit for showers as DW likes long hot showers in the morning. Heating the rig is just a humming sound. Wouldn't have another coach without it....Dennis

Question....How does all this work and let's say the AquaHot/Hydronic, system fails and whether or not you're boon docking or not, what do you do for hot water, heat, etc....and until you get it fixed?
I would guess the genset for space heaters, but how about the hot water and if I'm to understand this thing correctly, most everything is dependent upon it working, instead of having individual self contained appliances. I'm also assuming that the range is electric and needs the genset, correct?

If your Aqua Hot system failed completely, you would not have hot water or the ability to heat the coach beyond what you could do with electric heaters (generator or shore power) or overhead heat pumps.

The Aqua Hot has both electric heating element/s and the diesel burner. It seems that issues with the diesel burner (Webasto) are more common than any issue with the electric heating element. However, if the burner will not work, the electric element is limited in how much hot water or heat it can provide. But, you can still have some hot water with just the electric element.

[Mile_High]

For the MHs we looked at, in general the hydronic heated units had 150 gal diesel tanks whereas the others only 100 gal.