Understanding The Major Systems - Aqua-Hot 400 Series Service Manual

This Service Manual is designed to aid trained and
qualified service technicians with the process of trouble-
shooting and servicing the Aqua-Hot 400-P01 hydronic
heating system.
The Aqua-Hot 400-P01 heating system features a 12
Volt-DC powered Propane-burner and a 120 Volt-AC, 1650
Watt electric heating element. These two heating sources
are used in conjunction with an FDA-approved
"GRAS" (Generally Recognized as Safe) propylene glycol
based boiler antifreeze and water heating solution in order
to provide a continuous supply of domestic hot water, inte-
rior/fresh water tank heating and independent interior zone
heating. Be sure to reference the cut away diagrams on
pages 9-12 for complete component over view.
Should any additional assistance be needed, please
contact the technical support department at 1-800-685-
4298, Monday through Friday, between the hours of 7 a.m.
and 4 p.m. Mountain Standard Time.
Understanding the Aqua-Hot 400-P01's Major Systems:
The basis for the Aqua-Hot heating system's functionali-
ty is the antifreeze and water heating solution, which is
comprised of water that is distilled, de-ionized, or soft and
FDA-approved, "GRAS' propylene glycol based boiler anti-
freeze. Through this solution's ability to maintain and trans-
fer heat, the Aqua-Hot's two major systems; the domestic
water system and interior heating system are able to func-
tion effectively. This antifreeze and water heating solution
is contained within the Aqua-Hot's boiler tank and is heated
by the Propane-burner/Electric Heating Element when their
operating criteria are met.
In order for the Propane-burner to be considered as a
heating source, it must have an adequate gas supply, re-
ceive power from the electronic controller, and be selected
as a heating source from the interior switch panel.
In order for the electric heating element to be consid-
ered as a heating source, it must receive power from either
a generator or from the shore power and be selected as a
heating source from the interior switch panel.
Once the antifreeze and water heating solution reaches
operating temperature (as determined by the Aqua-Hot's
control thermostat), the domestic water system, and the
interior heating system are permitted to operate as needed.
Domestic Hot Water Priority System:
The Aqua-Hot 400 is a Domestic Hot Water Priority Sys-
tem. This means that the Aqua-Hot cannot heat the interior
of the motor home and produce continuous hot water sim-
ultaneously. When the domestic water is being used, the
interior heating system will shut down until the demand for
domestic hot water ceases.
The domestic hot water priority system is responsible for
providing hot water whenever a hot water faucet is opened,
(i.e. shower or sink).
When hot water is requested, domestic water from the
motor home's fresh water supply is transported through a
copper coil in the Aqua-Hot's boiler tank where heat is
transferred from the heated antifreeze and water heating
solution to the domestic water flowing through the copper
coil. The heated domestic water then flows through the tem-
pering valve to be mixed with cool water from the motor
home's fresh water supply. This achieves an appropriate
temperature before it flows to the faucet requesting hot
water.
Interior Heating System:
The interior heating system is responsible for providing
heat to the motor home's interior in order to maintain the
temperature at a comfortable level.
For interior heating, it is the motor home's interior room
thermostats that trigger the Aqua-Hot's interior heating sys-
tem. When a thermostat recognizes that the heat is re-
quired in a particular area, it sends a signal to the Aqua-
Hot's electronic controller. The Aqua-Hot responds by acti-
vating the circulation pump for that zone, which sends the
heated antifreeze and water heating solution through the
heating loop corresponding to the zone requesting heat.
The fans on the heat exchangers in the zone calling for heat
are also activated; therefore, as the heated solution flows
over the heat exchanger's fins, the heat is transferred to
those fins and dispersed into the interior of the motor home
by the fans. The Aqua-Hot will continue to send the heated
antifreeze and water solution through the loop, which re-
turns the cooled solution to the Aqua-Hot's boiler tank to be
re-heated before being sent back through the loop again.
This process continues until the pre-set temperature of the
interior is reached and the interior room thermostat signals
the electronic controller that heat is no longer required.
© Aqua-Hot® AHE-400-P01 Service Manual Rev.B June 2014
Section #: Title
Introduction to the Aqua-Hot 400LP
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