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SECTION 4
MAINTENANCE PROCEDURES
Every
DeVO/MC44
is thoroughly
tested
and
"burned-in" at the factory to make sure that all
of the product specifications are being met. To
assure continued trouble-free performance vari-
ous maintenance
procedures
should
be per-
formed on a regular basis by a qualified DeVilbiss
dealer. The following maintenance
instructions
are provided as a guideline.
A.
Testing and Calibration
1.
OXYGEN
CONCEN-
90
TRATION
(Percent
+3)
Turn the power switch to the "ON" posi-
tion and slowly turn the flow meter con-
trol knob (6 Fig. 2) and note that the flow
rate is variable from
0 to 5 liters per
minute.
When the unit is first turned on (or if not
used for an extended
period of time) it
may require up to 30 minutes for the oxy-
gen concentration to stabilize. The flow
rate may drift slightly during this period
of time and the oxygen concentration will
gradually increase to a steady value at a
specific flow rate.
When
the
oxygen
concentration
has
stabilized, an oxygen analyzer should be
attached to the oxygen outlet fitting (7
Fig. 2) to test oxygen concentrations at
various flow rate settings. The analyzer
should be calibrated prior to taking an
oxygen
percentage
reading
(See
note
under B-6). As the flow rate is increased,
the percent of oxygen in the delivered gas
decreases,
though
the actual
volume
of
oxygen delivered per minute
is greater.
The range of oxygen
delivered
at the
outlet for various flow rates is shown in
the graph below for the MC44.
100
80
MC44
(240 Volt)
70
ο
1
2
3
4
5
FLOW (Liters Per Minute)
Oxygen Production Vs. Flow Rate
B.
Routine Maintenance
1.
Humidifiers - The humidifier (6 Fig. 3)
should
be cleaned
daily or as recom-
mended
by the manufacturer.
It should
be washed
in warm soapy water, rinsed
thoroughly, and refilled. Be careful not to
overfill.
The
tubing
and
prescribed
cannula or mask should also be cleaned
according to manufacturer's recommen-
dations.
Gross Particle Filter - The gross particle
filter (6 Fig. 4) should
be removed
and
cleaned weekly.
To remove and clean:
A.
Turn the knob counterclockwise
1/4
turn and remove the entire assembly
(See Fig. 5).
B.
Wash
the assembly
in warm
soapy
water and
rinse. Shake
excess water
from the filter.
C.
Use a lint-free cloth or paper towel to
dry filter. Be sure filter is completely
dry before replacing.
D.
Filter
may
also
be
cleaned
by
vacuuming.
NOTE: The gross particle filter should be
monitored more closely in environments
with abnormal
amounts
of particulate
matter
in the
air.
Operation
of the
DeVO/MC44
without the gross particle
filter will prematurely occlude the felt
pre-filter and cause a decrease
in unit
performance.
Felt Pre-Filter - The felt pre-filter (2 Fig. 7)
should be changed approximately once a
month under normal conditions.
To replace the pre-filter:
A.
Rotate
the
filter housing
(3 Fig.
7)
counterclockwise
to remove
it from
the intake bacteria filter (5 Fig. 7).
B.
Remove the cap (1 Fig. 7) on the filter
housing and pull out and discard the
used filter pad (2 Fig. 7).
C.
Insert a new felt pre-filter pad
into
the housing and replace the cap on
the housing.
D.
Place the filter housing on the bac-
teria filter and
turn
clockwise
until
snug.
10/87
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