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Furnace Operation
NOTE: The “Hot Circ
Pump” breaker in the
AC panel and the
inverter, shore power,
or the generator must
be on for the furnace to
operate!
The furnace mode of operation is controlled by a master switch to the right of the lower
helm wheel near the doorway.
The switch has three settings:
Off
The heating system is “all off”
System Heat
The Diesel Furnace will supply heat if called for by the thermostat
Engine Heat
The starboard engine (if running) will supply heat if called for by
the thermostat
Select the desired mode. After the mode is set, set the desired temperature at any of
the thermostats throughout the boat.
When a thermostat calls for heat, and the switch is in the “System Heat” position,
the first time the furnace runs after the master switch is turned on it will take a few
minutes while the furnace starts and brings the circulating water to the needed
temperature before the fans start heating the boat: Be patient! (The furnace’s has a
built-in computer controlling its functions.) The furnace will then supply heat to the boat
until the thermostat senses it is warm enough, then the computer will shut off the fans
while the furnace goes through a “cool-down” cycle. You need not do anything but set a
thermostat!
In the “Engine Heat” position, the heat comes from the starboard engine, and will
come on more quickly if the engine has been running.
As you can see, this furnace system is very flexible and a great addition to the boat! As
long as the batteries can support the modest DC power requirement of the fans and furnace
blower, you will have plenty of quiet heat. In fact, this use of the house batteries’ energy for air
circulation is a good reason to limit use of the furnace to times when passengers are awake,
unless the boat has shore power available.
Furnace Blower Controls
“Fan Heater” controls are located throughout the boat in areas
where there are no thermostats. These will supply heat to that area
when the switch is on “Low” or “High” and the furnace is running.
These switches should usually be on LOW or
HIGH to be sure the furnace can effectively
supply heat to the boat, and not run extensively
and inefficiently in its “idle” mode.
Mode switch on left, the switch on right at helm is for the defrosters..
Section 4M: Furnace & Air Conditioning 4.33