16
ACCUMULATOR PRESSURE TEST
To check accumulator pressures:
1. Make sure the unit is “Off.”
2. Remove front and back cabinets.
3. Use the pressure-vacuum gauge (part #PVO2D-60
1) and pressure
test assembly (part #303DZ-637) included in the Service Kit.
4. On non-OSD and early-OSD models remove the
1/16" (1.6
mm) diameter tubing from the accumulator tank fitting and
attach the
1/16" (1.6 mm) diameter tubing on the other end
of the pressure test assembly to the accumulator tank fitting
just vacated above.This tubing goes from the accumulator to
the pressure transducer on the PC board.
On later OSD models remove the
1/16" (1.6 mm) diameter
tubing cap (part #370-0035-100) from the acumulator tank
fitting and attach the pressure test assembly to the tank fitting
just vacated. Use the tubing cap to plug one side of the
pressure test assembly.
5. Install the gauge on the pressure test assembly.
6. Turn the unit “On” with the flow rate set to maximum recom-
mended flow.
During each timed cycle, the average pressure in the oxygen
accumulator will rise and fall.
NOTE: Normal pressures observed depend on altitude and
flow rate. Increases in altitude and flow rate will slightly
decrease accumulator pressures. Decreases in the two variables
will slightly increase accumulator pressures. Acceptable accu-
mulator pressure swing ranges at various altitudes at the maxi-
mum recommended flow are identified in the “Specifications.”
NOTE: A defective check valve may cause a rapid drop in
accumulator pressure below the minimum value.
NOTE: A defective compressor will be indicated by slowly
rising pressure. Pressure may only reach a certain level and
then stop.
Low oxygen concentration levels and accumulator pressures
higher than normal may indicate defective sieve beds. Severely
contaminated beds may also cause the pressure relief valve on
the compressor to open.
NOTE: A malfunctioning four-way will also cause high accu-
mulator tank pressure and activation of the pressure relief
valve. In this case it should be determined whether the prob-
lem is with the sieve beds, four-way, or both.
CAPACITOR
The capacitor enables the compressor to start and run by
supplying voltage to the windings of the compressor motor.A
defective capacitor will result in the compressor running slower
or not starting.
WARNING: Electric Shock Hazard.When replacing
the capacitor, do not touch the terminals or allow
metal objects to come in contact with the terminals
on the capacitor.The capacitor may hold a charge for
several days after the unit is turned off.
If a defective capacitor is suspected, a new one must be
installed.The capacitor is strapped into a well molded into the
bottom of the unit (Figure
10) next to the cooling fan.
To replace the capacitor:
1. Make sure the unit is unplugged from the wall outlet.
2. Remove the front and back cabinets.
3. Remove the compressor.
4. Disconnect the two wires from the terminals on the capacitor.
5. Cut the nylon cable tie holding the capacitor in place and
remove the capacitor.
6. Reconnect the wires to the new capacitor.
7. Install the new capacitor and secure with a new cable tie.
8. Replace the compressor.
9. Replace the front and back cabinets and secure with the
six screws.
COMPRESSOR
The DeVilbiss Oxygen Concentrator uses a double-head, oil-
free compressor.The compressor is secured to the compres-
sor plate with four rubber motor mounts.
A compressor that is worn or defective may:
• cause pressure to rise slowly.
• cause excessive noise and/or vibration.
• cause lower oxygen concentrations.
A worn or defective compressor can be caused by a defective
internal component such as:
• reed valve
• o-ring
• gasket
• Teflon
®
ring
These components are included in the Compressor Service
Kit (part #505DZ-643).
NOTE: A built-in thermal cutoff switch will shut the compressor
off if it becomes overheated.This protects the compressor from
damage caused by heat build-up. (Some models have an auxiliary
thermostat mounted within the compressor compartment.)
NOTE: A pressure relief (PR) valve is located on the pressure
head to prevent high pressure build up in the system should a
component malfunction occur.
COMPONENT TESTING, REPAIR, AND REPLACEMENT
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