Aqua Heater

[Bernard Haag]

Pete, I have tried everything on your very helpful step by step directions. But.....where is the electical switch? I have a switch that says heater just ender the sink with the instant water heater and garbage disposal.... Is this it.... hope you can help further......

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From: Pete Masterson
To: WanderlodgeForum@yahoogroups.com
Sent: Tuesday, September 29, 2009 11:16:25 AM
Subject: Re: [WanderlodgeForum] Aqua Heater

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 experienced 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"

On Sep 29, 2009, at 5:40 AM, Bernard Haag wrote:

thanks for the help I will try it today

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From:Wayne Kotila <"waynekotila@yahoo.com">
To:"WanderlodgeForum@yahoogroups.com"
Sent:Monday, September 28, 2009 10:47:14 PM
Subject: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

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From:bhaagrealtor <bhaagrealtor@<SPAN class="Apple-converted-space">yahoo.com>
To:WanderlodgeForum@ yahoogroups. com
Sent:Monday, September 28, 2009 9:53:16 PM
Subject:[WanderlodgeForum] 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