Service manual

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© January 2013 Aqua-Hot
®
600-D01 Series Hydronic Heating System Service Manual - Rev. A
When the engine preheat system is activated via the interior
switch panel, the motor home’s engine coolant is circulated
through a dedicated copper coil in the Aqua-Hot’s boiler
tank, where heat from the antifreeze and water heating solu-
tion is transferred to the motor home’s engine coolant. The
heated engine coolant is then transported back to the engine
where it transfers the heat to the engine to gradually warm it.
Additionally, the Aqua-Hot 600 includes a Motor aide fea-
ture, which uses the circulation of the motor home’s engine
to transport the engine’s coolant from the Aqua-Hot’s boiler
tank to the motor home’s warm engine and back to the boiler
tank. Through this process, the boiler tank is kept heated,
which reduces the time required to bring the tank to operat-
ing temperature for interior heat and continuous domestic hot
water. This Motor aide feature is part of the engine preheat-
ing feature and plumbing system, and requires no action on
the user’s behalf to function.
Interior Heating System:
The interior heating system is responsible for providing heat
to the motor home’s interior in order to maintain the temper-
ature at a comfortable level.
For interior heating, it is the room thermostats that trigger the
Aqua-Hot’s interior heating system. When a thermostat rec-
ognizes that heat is required in a particular area, it sends a
signal to the Aqua-Hot’s electronic controller calling for
heat. The Aqua-Hot responds by activating the circulation
pump for that zone, which sends the heated antifreeze and
water heating solution through the Heating Loop correspond-
ing to the zone requesting heat. The fans on the heat ex-
changers in the zone calling for heat are also activated; there-
fore, 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. Until the thermo-
stat signals that heat is no longer required, the Aqua-Hot will
continue to send the heated antifreeze and water solution
through the loop, which returns 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.
AC Circuit:
Although the diesel-burner is the primary heating source for
the Aqua-Hot and is necessary for providing continuous do-
mestic hot water, an alternate heat source exists for moderate
temperatures, which functions with an AC circuit. Whenever
the motor home is connected to an AC power source -
plugged into shore power or using a generator, the Aqua-
Hot’s electric heating elements (2) have the ability to func-
tion in order to provide heat for the boiler tank.
When the antifreeze and water heating solution falls below
operating temperature (as determined by the control thermo-
stat), a signal is sent to the electronic controller requesting
heat. Because the electric element switch is activated on the
interior switch panel, the DC power from the electronic con-
troller is permitted to flow to the AC relay, which activates
the relay in order to allow AC power to flow to the electric
heating element. When the electric heating element receives
power, it becomes active and supplies heat to the boiler tank
until operating temperature is reached.
SECTION 1: INTRODUCTION TO THE AQUA-HOT 600 SERIES
NOTE: The Aqua-hot 600D is equipped with 2 - 2000 watt
120 Volt A.C. electric heating elements. The Aqua-Hot
675D is equipped with 1 - 2000 watt 120 Volt A.C. Electric
element along with 1 - 4500 watt 240 Volt A.C. electric
heating element. To operate both electric elements simulta-
neously, the motor home must be plugged into a 50 amp
circuit. Therefore, when there is less than 50 amp service
provided, there is a Hi/Low switch where only one electric
element can be activated by switching the switch to low.