Safety Instructions
©Aqua-Hot® 250 Diesel Series Use and Care Guide p. 5
Safe Operation
The Aqua-Hot Heating system consists of an electric
heating element and a burner. The electric element
and/or the burner heat a propylene glycol and water
mixture, that fl ows through tubing and into heat
exchangers to heat a zone that calls for heat. The
heating system also heats domestic water for hot
water use in the shower or at hot water faucets.
To safely and properly operate the Aqua-Hot 200 Series
heater, please make sure that the fl uid level is up to
the “COLD” level line on the expansion tank before
heating. If the heater has already been activated and
running, the fl uid should be to the “HOT” level.
Locate the Aqua-Hot switch panel inside the coach
(contact the vehicle manufacturer if unable to fi nd),
turn on either the “ELECTRIC” switch to turn on the
Electric Element or “BURNER” switch to turn on the
burner. It will take approximately 20 minutes to get
the glycol fl uid up to operating temperature. After the
tank is to temperature, you can turn on the heat on
your coach thermostat or run hot water.
General Care
The Aqua-Hot 200’s fl uid levels should be checked regularly
to ensure it is at the proper level. It should be checked when
the Aqua-Hot is at maximum operating temperature, when
the burner completes a cycle or when the electric element
disengages. The level should be at the “HOT” mark on the
expansion tank.
It is necessary to take precautions during any user
maintenance. Note that the fl uid will be very hot, and any
scalding hot vapor or coolant could cause serious burns or
injury.
Intended Use
This manual explains the operation and care of the Aqua-Hot
heating system.
These instructions are approved for the Aqua-Hot 200 series
model for recreational vehicles only. Not for use in boats.
Service and repairs may only be carried out by an authorized,
factory-trained Aqua-Hot technician. The heating system must
be installed/serviced in accordance with local codes, or, in the
absence of local codes, follow NFPA 1192.
• The vehicle owner is responsible for correct operation of
the appliance.
• Make sure to properly winterize the Aqua-Hot’s domestic
water system when not in use and/or any time the heater
is stored where freezing temperatures may be experienced.
The Aqua-Hot warranty will not cover claims for freeze
damage. Please refer to page 14 for proper winterization
of the Aqua-Hot.
• In order to provide the best freeze protection, boil-over
protection, anti-corrosion, and rust protection, a mixture
of 50/50 Propylene Glycol antifreeze and distilled water is
recommended.
• The mixture may be modifi ed to provide the most adequate
freezing, boiling, and rust/anti-corrosive protection. A
50/50 mixture of Propylene Glycol and distilled water has
a freeze point of approximately -29°F and a boiling point
of approximately 223°F. Reference page 18 for measuring
the antifreeze mixture with a refractometer.
Hot Water System
When hot water is requested, domestic water from the
coach’s fresh water tank is transported through the domestic
copper coil, that goes into the boiler tank located in the Aqua-
Hot. The water is then heated by the heated antifreeze and
distilled water solution. The heated domestic water then fl ows
through the tempering valve to be mixed with cool water from
the fresh water tank to achieve an appropriate temperature
before it fl ows to the faucet.
Figure 1
