Aqua Heater

[Ralph Fullenwider]

Pete:


This is the best read I have seen on this system, out standing. Thank
you, am putting the write up in my hard file for future reference.



Safe travels,


Ralph & Charolette Fullenwider

'84 FC 35 "Ruff Diamond"

Duncan, Oklahoma


At 10:16 AM 9/29/2009 -0700, you wrote:

The AquaHot is set up with three
sources of heat:


1. Engine heat (while engine is running) -- this also allows the engine
preheat to operate "in reverse."

2. Electrical heating element (2000 watts) while connected to shore
power. This is controlled through a breaker on the main 120 VAC power
panel.

3. Diesel burner. This has 12 vdc power (Lord knows where the fuse is)
and is controlled by a switch labeled "Hydronic Heat" on the
dashboard. The switch has a green light that shows when the burner is
enabled (but not necessarily running).


The selection of heat source is by default and or controlled by
thermostats.


Engine heat is the default heat source. When the engine is operating,
there is no shore power, so the AquaHot will get heat from engine. The
hydronic heat switch should be off when the engine is operating.


Using the AquaHot for internal heating purposes requires that the Dometic
thermostat(s) be set to "gas heat" AND that the A/C switches on
the sub-dashboard (left side) be ON. The bathroom has a separate
thermostat that is not remotely controlled. In cold weather, on the road,
I usually would set the mid-coach thermostat to operate the hydronic
heat, set at a comfortable level. Since the front of the coach was
sometimes cooler, supplement heat from the chassis system might be
used.


When hooked to shore power, the electric element operates. It has a
thermostat control to maintain 190 degree temperature of the water. (A
mixer valve in the AquaHot is used to adjust the output water temperature
to avoid potential scalding.) Since the AquaHot is a
"continuous" hot water heater, as the water flows, it raises
the input water temperature as it flows through the internal tubing.
Often, cool water input can not be adequately heated by the electric
element alone (especially when using the shower).


If the diesel (hydronic heat) switch is on, ! when the output water
temperature drops below 180 degrees (before the mixer valve), then the
diesel burner is signaled to ignite. (This gives priority to the electric
element.) The output of the diesel burner is significantly greater than
the electric heating element and it generally is able to keep up with the
water flow raising the input water sufficiently for comfortable showers
and other needs. In extremely cold situations (input water temperature
below 40 degrees), even the diesel burner is insufficient to raise the
input water to a comfortable level. This is where you learn that the
AquaHot has the equivalent capacity as about a 15 gallon water heater.
(Note -- this is a similar "feature" of all so-called tankless
water heater designs.)


Draw your attention back to the green light by the hydronic heat switch.
Depending on several variables, from time to time, the diesel burner
_may_ not successfully ignite. A "flame detector" then shuts
off the system (for safety) and the green light by the switch will go off
(even though the switch is on). This is not common, but I've had it occur
occasionally. Of course, this happens just after you step into the shower
and you detect it by running out of hot water!


If the green light goes off, to re-set, turn off the hydronic heat
switch. Wait about 10 seconds (to allow the safety switch to reset) and
turn the hydronic heat switch back on.


Regular annual servicing the diesel burner will reduce the likelihood of
having the diesel burner fail to ignite. The annual service replaces the
burner nozzle and re-adjusts the position of the electronic ignition
(spark plug-like) probes.


I note that in cold weather, the electric element alone is usually
adequate to maintain the 40 degree temperature (thermostat on front
bulkhead, curb side) in the basement that protects the tanks, plumbing,
and other basement located items from freezing. This was the case down to
14 degree temperatures! I exper ienced in Colorado in December. At some
point, however, colder temperatures are likely to require the diesel
burner.


Finally, the engine preheat. This device, controlled by a switch on the
panel on the street side above the driver's head, uses the AquaHot to
pump water through the engine, warming it for a cold-start situation.
It's very effective and in most situations running it for 2 or 3 hours
before a planned start is sufficient. This is different from the block
heater (red-lighted switch near galley in my coach) that provides gentle
electric heat (shore or generator power required) to the engine block
and/or oil pan. The block heater requires 12 or more hours for effective
impact.


In "moderate" cool weather, where the ambient temp is below 60
degrees, using the engine preheat for as little as a half-hour, often
makes the Series 60 much easier to start. If an engine start is desired
when ambient temps have been (or are) below 50 degrees, then using the
engine preheat for at least an hour is almost essential.


Be sure to turn off the engine preheat switch _before_ starting the
engine.



Pete Masterson

(former) '95 Blue Bird Wanderlodge WBDA 42

El Sobrante CA

"aeonix1@mac.com"




Re: [WanderlodgeForum] Aqua Heater




To start your aqua Hot on diesal, there is a switch on the dash and it
should be labeled hydronic heat.

Wayne

1996 PT42




From: bhaagrealtor <bhaagrealtor@
<a href="http://yahoo.com/" target="_blank">yahoo.com>

To: WanderlodgeForum@ yahoogroups. com

Sent: Monday, September 28, 2009 9:53:16 PM

Subject: [Wan! derlodge Forum] Aqua Heater






can some tell me where I should be looking for the diesel switch and
electrical switch on my PT42 1995 model...thanks. ..Bernie