01 March 2005
2-6.5. DRYING WITH CIRCULATING AIR DRYING
OVEN. The Circulating Air Drying Oven, (Volume IV or
The motion of air against other materials can
electronic components (such as unpressurized
generate static charges that degrade or destroy
instruments), control boxes, PCBs, and similar devices.
ESD devices. Care must be exercised during
The circulating air drying oven shall never be operated
handling/repair of these items. Use the
above 130°F (54°C) when drying avionic equipment or
recommended shop practices outlined in
components. Damage may result from overheating of
discrete electronic circuit components. Procedures for
the operation of the circulating air drying oven are as
2-6.6.1. Blow off excess water with dry air or dry
nitrogen at no more than 10 psi pressure. Deflect air
off interior back and sides of enclosure to diffuse jet.
2-6.5.1. Blow off excess water with dry air or dry
nitrogen at no more than 10 psi pressure. Deflect air off
interior back and sides of enclosure to diffuse jet.
Check the temperature dial (or control
c a l i b r a t i o n ) periodically to ensure the
temperature setting is correctly calibrated.
Older circulating air drying ovens may have
2-6.6.2. Set the temperature control at a maximum of
uncalibrated dials or controls for setting the
oven temperature. These ovens shall be
calibrated so that the 130°F (54°C) temperature
2-6.6.3. Place the component(s) in the oven and close
setting is "red lined" on the dial or control.
the door. If a timer is available, set it for 1 to 2 hours.
Opening and closing the oven door during drying will
2-6.5.2. Set the temperature control at a maximum of
increase the drying time slightly but not appreciably.
This is considered one of the advantages of the forced
air drying oven over the circulating air type.
2-6.5.3. Place the component(s) in the oven and close
the door. If a timer is available, set it for 3 to 4 hours.
2-6.6.4. Upon completion of the drying cycle, remove
2-6.7. D R Y I N G WITH VENTED OVEN (BULB
Opening and closing the oven door during
drying will increase drying time. This is due to
TYPE). Vented drying oven procedures are as follows:
diffusion of hot, dry air in the oven cabinet with
cooler, more humid air from the surrounding
2-6.7.1. Blow off excess water with not more than 10
psi dry air pressure or dry nitrogen. Deflect air off
interior, back, and sides of enclosure to diffuse jet.
2-6.5.4. Upon completion of the drying cycle, remove
2-6.7.2. Dry the equipment at approximately 130°F
(54°C) for 3 to 4 hours.
2-6.6. DRYING WITH FORCED AIR OVEN. The
Forced Air Drying Oven (Volume IV or V, Chapter 3) is
2-6.8. DRYING WITH VACUUM OVEN. Vacuum oven
the most efficient of the drying ovens. This unit can be
drying procedures are as follows:
used to dry all types and sizes of equipment and
components. The procedures for the operation of the
forced air drying oven are as follows: