Location And Use Of Internal And Check Dampers - Field Controls M Manual

For larger plants, drafts over the fire (taken through openings in the fire doors, etc.) of .10" to .15" should be
enough, and .20" should be the maximum. Greater economy will be obtained with lower drafts.
To check the fire or to bank it, close the ash pit door tightly. It is permissible to use a check or hand turn
damper also, when banking the fire, should the ash pit doors fail to close tight enough. But if the ash pit draft
doors fit well it is more simple to open or close the ash pit air register by degrees to obtain the heat desired at
different times, rather than to change the settings at the smoke outlet of the furnace frequently.
When a thermostat and damper motor are used, install a Field Barocheck control instead of the standard unit.

LOCATION AND USE OF INTERNAL AND CHECK DAMPERS

With an oil burner, never use damper "A" (See Figure 6) or the check damper. Remove damper "A" and seal
the check damper closed. If the draft developed in the chimney is very excessive, so that control cannot fully
regulate it, damper "B" may be partly closed to supplement the control. But it must be securely locked so that
it cannot block the flue passage too much and cause a deficiency of draft. For safety reasons, usually it is
better to remove all internal dampers when an oil burner is installed. With a stoker, the same rules apply as
with oil. For a hand fired coal burning plant, it is permissible to use damper "A" of the check damper when
it is desired to bank the fire. The Field Barocheck combines the function of a check damper with that of a
barometric control all in one unit. If the draft developed in the chimney is very excessive, damper "B" may be
used by partly closing it, locking it there.
Figure 6
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