Sunrise Medical DeVilbiss 505DZ Service Manual page 30

C O M P O N E N T T E S T I N G , R E P A I R & R E P L A C E M E N T
To check accumulator pressures (Figure 24):
1. Ensure the unit is "Off."
2. Remove front and back cabinets.
3. Use the pressure-vacuum gauge (part #PV02D-601) and test fitting (part #303DZ-632) included in the Service Kit.
4. Remove the 1/16" diameter hose from the accumulator tank and attach it to the barbed fitting on the test fitting.
5. Attach the 1/16" diameter hose on the other end of the test fitting to the accumulator tank fitting.
6. Install the gauge on the test fitting.
7. Turn the unit "On" with the flow rate set to 5 LPM.
During each cycle, the pressure in the oxygen accumulator will rise to approximately 25.5 PSI (175 kPa) and the four-way valve will
shift to start a new 1/2 cycle. The pressure will then decrease to approximately 19 PSI (130 kPa) at 5 LPM. This minimum pressure
will vary according to flow rate. The higher the flow rate, the lower the pressure will drop in the accumulator tank. When the check
valve opens allowing oxygen to flow into the accumulator, pressure will start to increase until maximum pressure is reached (25.5 PSI
or 175 kPa) again starting another new 1/2 cycle.
NOTE—A defective check valve may cause a rapid drop in accumulator pressure, pressures below approximately 19 PSI (or 130
kPa) at 5 LPM, or a longer than normal cycle time. If a defective check valve exists, the manifold must be replaced; refer to
the section on servicing the manifold assembly.
Pressure-vacuum gauge
Figure 24
30
Test fitting
1/16" I.D. hose
(tubing to PC board)
Accumulator tank
Accumulator tank fitting
1/8" I.D. hose