Sig Marine Sig100, Руководство по эксплуатации и установке

Страница: 4 / 35

4
It is important to create and maintain a positive pressure inside the boat. High
winds can draw air out from the boat and thus create a negative pressure. This
condition can result in down drafts. Ensure that when you do have windows
open that they do not create a suction effect in the cabin due to the window’s
position and the wind direction. In a similar way, it is possible for the air intake
on your engine to suck the air out of a cabin if it is not properly vented.
Your heater is a natural draft appliance and it creates its draft pressure like a
chimney in a wood stove. The rising, heated air in the chimney pulls fresh
air into the heater as it rises up the chimney and exits the flue cap. The
greater the draft pressure, the more able the heater will be to resist strong
winds, overcome flue elbows that inhibit draft and the hotter you will be
able to get your heater without sooting. A CO alarm should be installed in
the boat. We also recommend the high heat shut-off kits available through
us.
4. How Does the Chimney affect the Heater?
The heater does not create the draft for a natural draft appliance to operate; it
is the chimney that creates the draft for operation. The purpose of a chimney
is to take the combustion products (smoke and gasses) from the appliance to
the atmosphere outside your boat, and at the same time, to draw air in for
combustion into the appliance. This movement of combustion air and
exhaust is called draft.
In essence, it is the difference in pressure between the air inside the chimney
flue and the outside air that creates this movement. Warmer, lighter gases in
the flue will move upward.
To keep the pressure conditions favorable, we need a tall column of warm
air inside the chimney, and cooler air outside. The warm air will tend to rise,
drawing the exhaust from the appliance out. As air exits the chimney, fresh
air for combustion is drawn into the appliance. The stronger the upward draft
in the chimney the more likely you won’t experience downdraft.
Important Factors of the Chimney
Since draft is a measure of pressure, chimney draft is affected by pressure
conditions in the boat. Several factors come into play:
1. Adequate air. First, there must be adequate air movement into the
boat to make up for the air exiting through the chimney. If the boat is
very tightly insulated, the volume of air drawn up the flue will exceed