AquaHot and Bay heater question

[Mike Shumack]

Someone asked about the operation of the Bay heater in their Beaver Coach. They wanted to know if the Bay heating would work with AquaHot turn On with the thermostat inside coach turned off.

I looked at my Owner's Manual and it only says the AquaHot must be On for Bay heating (the "snap disc turns on heat with temps below 45 degrees +/-). No mention of having to put the inside thermostat to "furnace" mode. That's what I replied. But another poster says the thermostat must be in Furnace mode or only the Bay blower will turn on - the burner won't fire up.
 
I'm in Fl so it's too warm for me to test/verify operation. I'm curious about this now. Could be a misprint in the manual - or other poster is right.

Does anyone know for sure?

[Fred Brooks]

    Hi Mike,
I am pretty sure the Aqua-hot has to be turned on and the T-stats set for gas heat. The reason I believe this to be true is the Aqua hot will heat the coolant on electric (if available) or use diesel (wabasto). The t-stat talks to the zones of the aqua hot to know if they are satisfied. As I recall, the holding tanks heat exchanger is daisy chained to the lavatory circuit or the bedroom Zone (or t-stat). Set the t-stats to 45 degrees and all is good. If the coach is not plugged in, and allowed, turn on the AGS system for Generator stand-by when the batteries require charging. Merry Christmas Mike, Fred

[Scott Shearer]

Mike,

Maybe it depends on the Aqua-Hot model (or coach model and year), but what your owner’s manual says is very similar to how our wet bay heat exchanger works, except ours is controlled by an adjustable remote bulb thermostat.

Basically, the wet bay heat exchanger works just like the any other zone when that zone is set to Furnace. The wet bay fan (and circulation pump #3) will run ANYTIME the wet bay thermostat is calling for heat, even if the Aqua-Hot is off and the boiler is cold (which is not a good thing).

So long as diesel and/or electric are selected, the boiler will attempt to maintain temperature. Interior thermostat settings have no effect on the wet bay heat exchanger or burner operation.

Anyway, that’s how our system works.

It would be pretty unhandy if the interior thermostat had to be set to Furnace to allow the burner to fire. If that was the case, you wouldn’t have any domestic hot water unless the thermostat was set to Furnace.

Aqua-Hot model: AHE-100-04S

-Scott

[Fred Brooks]

   Scott,
   You are correct that the Aqua hot has to be turned on regardless of any interior t-stat calling for heat. Selecting electric or diesel will bring the aqua-hot up to operating temperature including access to hot water if desired. I think Mike is inquiring about how to activate the holding tank compartment heat exchanger. Why would someone only want to heat the storage compartments and holding tanks from freezing and not the interior plumbing from freezing? A simple way to prove operation of the holding tank heat exchanger is to do the following. Purchase a can of compressed air duster used to clean computer keyboards. If you invert the can of duster, you get liquid nitrogen (or propellant) when pulling the trigger. Remove the access cover to the holding tanks compartment. Locate the "disc" or "bulb" thermostat that activates the heat exchanger. Squirt the inverted duster on the t-stat until frosty. The heat exchanger fan should come on. Hope this helps, Fred

[Lee Welbanks]

We had a bunch of company here and used the Patriot Thunder as a hotel room for guests. Charged up the coach with water and turned on the Aqua hot to supply hot water for the folks. None of the thermostats were ever turn on and I know that the basement heat will come on because I turn down the basement thermostat to just see if it would work.
As Fred stated this will not protect the rest of the plumbing system in the coach from freezing as you are not moving any water.

[Mike Shumack]

You both make good points.
It is the Bay heating (freshwater tank and waste tanks) that he was concerned about. The guy who asked was parking his coach in storage and wanted to be sure his tanks didn't freeze. He was not occupying the Coach. I guess the thought was to turn on the AquaHot and leave it On while not there - and it would only fire up if the Bay temp dropped below 40.
 
However now that I am reading your posts and thinking about it more, I think leaving the AquaHot On would not be such a good idea. I doubt he wants to waste fuel keeping his domestic water at 110 degrees, and if the interior thermostat needs to be in furnace mode, then he would be wasting fuel keeping the inside warm (even at the lowest the temp setting).

I don't think anyone (in the previous forum/discussion) was considering the rest of the plumbing system. So does one need to "winterize" - even if they are only staying in the cold for a short time? Or are you just saying, you want to keep the bay and Inside of Coach warm - so turn furnace on?

[Fred Brooks]

   Mike,
If you are living in the coach, no. If you store your coach in the winter months and the possibility of freezing is common, then winterize the aqua-hot and the freshwater system. Fred