Instruction manual

4
SIG MARINE PRODUCTS MANUAL REV S4.
BALANCED DRAFT SYSTEM
The Balanced Draft System is optional; it is not required but can be added later if you wish.
The Balanced Draft has 2 major advantages. In most cases it will eliminate “back drafting or
down drafting” (Page 8) and allows the heater to use outside air for combustion rather than cabin
air. This increases the safety and efficiency of the heater. The balanced draft system can be
mounted on all our heaters No. 100, 120, 170, and 180. Unfortunately it can not be mounted on
the No. 200 and 250 stove.
The Balanced Draft is simply having the air feed for the heater coming from outside the boat
immediately adjacent to the exhaust pipe.
This means that any wind conditions that affect the exhaust will affect the air intake
simultaneously - thus a balanced draft. Similarly the heater will not experience any barometric
pressure changes in the boat because the air intake for the heater is through the 3” opening in the
bottom that is connected to the outside air through the air intake and the 3” hose. The air intake
must be as close to the exhaust as possible - no more than 3 feet away and free of all obstructions.
We want the intake and exhaust to experience the same conditions. The exhaust should be
approximately 12” higher than the intake. The air intake hose should be as short as possible with
as few elbows and bends as possible. We want a smooth flow of air to the heater.
The size of the hose for the air intake must be 3” - the same as the exhaust pipe. The Rain Caps
on the exhaust and the air intake must be identical.
If installing the Balanced Draft, the intake pipe may be 3” hi-heat flex hose, stainless steel or
aluminum pipe.