W:\ELECTRICAL\INSTRUCT\FURNACE\FURNACE GENERAL INSTRUCTIONS 2011.DOC
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01/2014
5-9
For Tempering Furnaces, open the exhaust and fresh air dampers enough to prevent
fouling of the work. Where significant amounts of smoke or moisture are being driven
off in the furnace process, it is necessary to exhaust enough air to remove this
material. Failure to provide sufficient ventilation may result in condensation of oil or
solvent vapors inside furnace walls with a resulting risk of fire.
5-9.1
When the exhaust is increased, the fresh air intake must also be increased.
Failure to do this will result in cold spots within the furnace, particularly around the
door, since air will be drawn in past the gaskets. When the fresh air intake damper
is properly adjusted, there will be a slight leaking of hot air out of the door gaskets.
The fresh air intake damper is located on the wall of the heat chamber.
5-9.2
Proper balance of the fresh air inlet and exhaust outlet are essential for uniform air
temperature. Room air entering the fresh air inlet expands when heated and
pressurizes the work space forcing air out the exhaust or past the door gasket. Too
much fresh air (or too little exhaust) can result in excessive leakage of hot air at the
door seal.
5-10
Where furnaces are equipped with louvered ductwork, the louvers may be adjusted to
give the best performance for your particular process. The louvers were originally set
at the factory in an empty furnace. Loading of your parts may affect uniformity. These
louvers are not designed for frequent adjustment and should only be changed when
absolutely necessary. Louvers should be opened where the work space is cold and
closed where it is hot.
5-11
Hot loads, tongs and other hot tools or fixtures such as shelves and loading trucks
should be located in areas clearly marked to warn plant personnel of the potential
danger of burns or fires caused by the hot parts.
