HearthStone Nestor Martin S31 Owner's Manual page 6

FLUE PRESSURE ADJUSTMENT REQUIREMENTS
The flue creates the negative air pressure within the stove which induces the air into the burner. For the correct
operation of the burner this air flow must be proportioned to the firing rate of the burner. The following chart below
illustrates the required negative air pressures relative to the burner settings, with the shaded band giving the
tolerance within which the burner will give satisfactory performance.
THE DRAFT STABILIZER
The draft stabilizer works by opening to provide an additional air supply to the flue whenever the flue's negative
pressure reaches its upper limit. This action checks any rise beyond this limit to maintain the correct negative
pressure within the stove.
This system of flue control is universally accepted as both effective and reliable, but because the
supplementary air it allows into the flue is drawn from the room, it is desirable to have it open as little as
possible.
Where the flue is either subjected to prolonged strong winds or the flue itself is of higher efficiency than normal,
the stabilizer may be unable to supply sufficient air to reduce the negative pressure adequately or be needlessly
wasting room heat by having to supply dilution air constantly.
A second regulator may be installed on the stove's flue if during start up the flue is found to be subjecting the
stove to a negative pressure which is too high for efficient combustion.
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