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C O M P O N E N T T E S T I N G , R E PA I R A N D R E P L A C M E N T
MOLECULAR SIEVE BEDS
The build and release of pressure in the sieve beds indicates the health of the
sieve material and the operation of contributing components. Determine 'good' or
expected pressures for your altitude by testing bed pressures on multiple oxygen
concentrators that are producing at least 93% purity.
Check sieve bed pressures at the accumulator tank using the manifold test point
or the accumulator tank "T" fitting. See Figures below
Accumulator "T" Fitting
NOTE– The pressure will rise and fall as it cycles through the rotary valve.
The pressure swing will be approximately 4-5 psi.
Also consider the acceptable pressure range for various altitudes as shown
below.
TYPICAL PEAK ACCUMULATOR TANK PRESSURE RANGE @ 10LPM
Altitude
0 to 457 m
0 to 1500 ft.
457 to 914 m
1500 to 3000 ft.
914 to 1524 m
3000 to 5000 ft.
To test sieve bed pressures:
1.
Remove the plugged piece of 1/16" tubing from the accumulator tank.
2.
Connect the pressure gauge to the test point and observe the cycling of
pressures. Refer to the section on Normal Operating Sequence and also
Accumulator Pressure Test.
a.
If it is determined that the valve is not cycling the pressure, refer to
the section on Rotary Valve testing.
b.
If the unit is cycling properly, allow it to operate for 20 minutes.
3.
After 20 minutes of operation, observe the high and low pressures and
check the oxygen concentration level.
a.
If the pressures are within the expected range and the oxygen
concentration is within specification, the sieve material is effective.
b.
If pressures are not within the expected range and/or the oxygen
concentration is not within specification, refer to the Simplified
Troubleshooting Table in this manual to determine the proper
corrective action.
NOTE– If the molecular sieve material is found to be no longer effective, first
search for the source of a malfunction in the system; then, for a cause for
contamination (such as leaks) and take corrective action.
To replace the molecular sieve beds:
NOTE– Make sure that the sealing caps remain on the new sieve beds until
just prior to connecting hoses and tubing.
1.
Ensure any contamination problem has been corrected.
2.
Ensure the unit is unplugged from the wall outlet.
Manifold
Psi
kPa
25-36
172-248
21-33
145-228
21-30
145.207
3.
Cut the plastic cable ties that secure the sieve beds to the internal structure
of the unit.
4.
Remove the tubing from the fittings at the top of each sieve bed.
5.
Remove the hose clamps and hose from the bottom of the sieve beds.
6.
Install new sieve beds in reverse order using new plastic cable ties.
Position the new beds so that the bed serial number label is at the top of
the unit.
7.
Leak test all connections with a certified leak detection solution such as
Snoop® or equivalent (must not contain ethylene glycol). Apply leak test
solution to all fittings and hose connections with unit running. If an air leak
is present, the solution will bubble. All leaks should be repaired before
putting the unit back in service.
CAUTION
Do not apply leak test solution to any part of the rotary valve or the
main PC Board assembly.
POWER CORD
To replace the power cord - 120 volt units
only:
1.
Make sure the unit is unplugged from the wall outlet.
2.
Use the Cabinet Removal instructions listed previously to open the unit.
3.
Disconnect the power cord connector.
4.
Note wire colors and socket locations before removing wires.
5.
Using a pair of duckbill pliers, squeeze the power cord strain relief and pull
it out of the base of the unit.
6.
Insert a new power cord through the hole in the base of the unit and secure
with strain relief.
7.
Insert sockets into connector housing and then reconnect the power cord
connector.
8.
Replace back cabinet and secure with the six screws.
POWER SWITCH
To replace the power switch:
1.
Make sure the unit is unplugged from the wall outlet.
2.
Use the Cabinet Removal instructions listed previously to open the unit.
3.
Note the position of the wires and switch before removing the wires from
the switch terminals.
4.
While squeezing the locking tabs on the top and bottom of the switch, push
the switch out of the front of the unit.
5.
Install the new switch in the correct orientation making sure that it locks into
position.
6.
Reconnect the wires to the switch terminals.
Switch Detail
*Red Wire
*Red Wire
* Either red wire can be connected to either left hand terminal of the switch
23
Brown Wire (or 2 Black Wires)
2 Black Wires (or 1 Brown Wire)
LT-2329
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Troubleshooting
