Sunrise Medical DeVilbiss 505DZ Service Manual page 33

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
NOTE—If the short cycle (D16 or D16 and D18) alarm has been activated, it must be determined whether the problem is with the
sieve beds, a failure of the four- way to shift, or a restriction of flow. A flow meter turned off or crimped tubing may cause such a
restriction. Short cycling would indicate bed failure and non- cycling would indicate a four-way valve malfunction.
If the molecular sieve material is found to be no longer effective, first locate the source of the malfunction or cause (such as leaks)
for contamination and take corrective action.
To replace the molecular sieve beds (after the problem has been corrected) (Figure 29):
1. Ensure the unit is unplugged from the wall outlet.
2. Remove the plastic cable ties that secure sieve beds to internal structure of the unit.
NOTE—Cable ties are reusable, do not cut; press release tab to loosen cable tie.
3. Remove the 1/4" I.D. tubing from the top of each sieve bed.
4. Remove the hose clamps and reinforced tubing from the bottom of the sieve beds.
5. Install new sieve beds in reverse order.The bed serial number label should be at the top of the unit.
NOTE—Ensure that the sealing caps are removed from the new sieve beds just prior to connecting hoses.
6. Leak test all hose connections with a certified leak detection compound.
Hose clamp
Cable tie
Left sieve bed
1/4" I.D. hose
1/2" I.D. hose
Hose clamp
Figure 29
Hose clamp
Hose clamp
33
Fitting
(top of sieve bed)
1/4" I.D. hose
Right sieve bed
Fitting
(bottom of sieve bed)