[Rod]

Rod,

Your water heater will be kept hot by the engine coolant when your driving, provided it’s not shut off, and your bay will keep warm. You can turn on your Webasto, set your thermostats and your Webasto will give you heat without actually firing the diesel burner. The engine will be hot and the Webasto pump will circulate the coolant to your heat exchangers.

I keep my valves for the hot water heater shut off because the water is scaulding when driving.

[Bob]

Thanks Tom.

What a great system. I am continually impressed!

[Archived]

One more thing Tom, do you know where the shut offs are for the hot water heater?

[Archived]

The hot water heater shut offs are above the heater itself. A valve for both the coolant in and coolant out.

Never worry about your bay freezing. You only need to keep heat in the water bay because it is the only one with water and plumbing and it is provided with a heat exchanger over the fresh water tank. That will put heat into the bay any time you have the Webasto or engine providing hot coolant. If the temperatures outside are warm enough so the Cruiseairs or the toe space heaters are keeping the house warm, the bay is going to be OK.

If you aren’t running the Websto or engine and are concerned about the bay you also have an electric bay heater mounted on the rear bulkhead with a thermostatic control near it. The switch for the electric heater is in the 120 volt electric panel. Kind of unnecessary. I never used it.

For running down the road, select the heat option on the OTR switch on the dash. It will keep you toasty warm.

[Peter]

Jon and others…..

The Aqua-Hot doesn’t have tanks like the Webasto…. what is the advantage of one over the other? We currently (as I’ve mentioned in other threads) have the Aqua-Hot system and thought that’s what I would want in our new coach if/when we order a new Prevost.

Since I’m a little green on these systems and only having Aqua-Hot, it seems to me having separate water tanks to worry about would be a slight disadvantage. Am I missing something?

Thanks, Mark

[Rod]

You have it backwards.. Aqua-Hot has it’s own coolant tank and the Webasto uses the engine coolant. Even though you have Aqua-Hot, the diesel burner is Webasto. So in short, if you have a bus with Webasto it uses the engine coolant to heat engine, hot water heater and heat exchangers (furnace). If you have Aqua-Hot, it has it’s own sealed coolant tank to do all the same thing the Webasto equipped bus does. The Aqua-Hot adds complexity to the system by means of a boiler and multiple pumps for each function. You will have a pump for each heat exchanger and the engine pre-heat. Your fresh hot water tank is actually built into the Aqua-Hot, were the Webato buses have a seperate hot water tank or sometimes like Marathon, two.

Hope that helps. I’ve had both and really like the Aqua-Hot because of the electric heating function without the nead to use the diesel unless it really gets cold or you need unlimited amounts of hot water. On the other hand, I like the Webasto because it’s a simple system and uses the engine coolant for all functions. Both work really well.

[Archived]

Rod Could you email me. I tryed to email you but it came back undelivered. I would like to talk to you about doing some work for us on the coach. treedocrwm@aol.com Thanks Rick

[Archived]

I’m not sure I understand what an Aquahot does that Webasto does not do.

My webasto heats my coach engine, coach interior, and my hot water. To do so it uses engine coolant which it circulates via a rather large robust circulating pump.

If I prefer to not use my diesel fuel, such as when hooked to shore power, my HW tank has an electric heating element, my engine has an electric heater and I have electric toe space heaters of the same size wattage as an Aquahot.

An Aquahot is built around a Webasto. It’s heat source is a Webasto unit. I believe it has individual pumps for each loop in lieu of one large pump. What exactly am I missing except for an added layer of complexity using its own coolant and heat trransfer?

Both systems work. The Aquahot is an easy install for a converter because it is all in one package, but go count the posts about Aquahot problems and consider that those are over and above any problems that might occur with the Webasto.

[David]

We are in Lincoln Nebraska. It is fiendishly cold here but inside we are nice and toasty!

Rick…..just sent you an email.

[Dean]

I agree with Jon. The converters that use AquaHot most likely do so to avoid th complexity of plumbing in hot water heaters, as it is pretty much a self-contained drop in system. My only problem with AquaHot(other than the added complexity) is when looking at used coaches. After a certain age(ten yrs.or more) depending how they have been winterized and maintained, there is potential for a nasty bill for replacement(10K+) down the line. George

[Archived]

Tom (Truk4u)… thank you. That was a good clear explanation.

I guess the part I was hung up on, is that the Marathon uses 2 water tanks. It just made me think that about the fact that we don’t have water tanks with the Aqua-Hot so it seemed to me to be an additional item to malfunction.

We have not had trouble with our Aqua-Hot per se in the 6.5 yrs. we’ve had the coach. A kitchen sink hose split causing the excess water to drip down on the Aqua-Hot computer board shorting it out. Otherwise, the Aqua-Hot ‘itself’ has been flawless.

Mark

[Archived]

Coach heat? This is the first year I will be using the OTR bus heat. Tried to use it last year …. nothing but cold air. Then I saw a valve down by the radiator on the drivers side of the coach. I am guessing I need to turn it on to circulate water through the coils ….. Right? Then what do I need to know? Does everything work great after that?

[Peter]

Mine had 2 valve Mike— one on the return and one on the supply– both same area. If it doesn’t work then you need to bleed air in two places. defroster. heat exchanger underdash. thumb type valve like on car rad with short hose to outside. and drivers side compartment where ac evaporator is is main bus heater core has simular valve. Then you will prob have to top off you antifreeze tank..Your elect controls are??? to me without seeing. The box on the floor in your picture is your cold air return for your heat system and has the sensor in it. It does sit directly above the hot rad /heat exchanger /bus heat that may need to be blead… Directly across under that side angle type duct under the window is the main upward discharge into the coach for both AC and Heat–pull it up and look you may want to do away with that whole duct work….FWIW Bob

[Corey]

We tried the OTR heat coming back from Nebraska. The green heat light was but all we got was cold air. Does the green light mean we have a problem or does it mean it is working?

[Archived]

Rod (or Nancy)….you have two options for heat while driving. The first is to use the OTR with the selector switch set in “heat” mode. When it cals for heat you will see the annunciator light.

For the OTR to work the valves need to be open. In the Webasto compartment there are a number of valves that have to be open, and I can’t remember if you also have a valve next to the radiator covered with a flap. If so that needs to be open. Also check in the OTR bay on the driver’s side and see if there are any valves in there. I can’t remember about that either, but I would look in there.

The second option for heat is the Webasto. Once the engine is up to operating temperature the Webasto will not fire, but it will provide heat through the various house heat exchangers, including one in the center of the lower dash.

If the coach was used in warm temps it might be the valves were closed to prevent coolant from circulating in an area that was being air conditioned. Both systems use solenoid valves so if all the valves are open I would verify the solenoid valves are functioning.