Simplified Troubleshooting - Sunrise Medical DeVilbiss 505DZ Service Manual

Simplified Troubleshooting

The key to simple troubleshooting is to recognize which type of problem exists and select the most effective approach to solving the
problem. The different types of problems and the approaches for solutions are as follows:
Type I-Unit runs for a while and shuts off.
Approach-Connect the pressure-vacuum gauges to the sieve bed test points and look for the proper cycling sequence. If something
in the sequence is incorrect, troubleshoot the appropriate components (i.e. if the right bed pressurizes first, troubleshoot the four-
way valve).
Type II-Power switch is in the "On" position and "Power" indicator light is illuminated, cooling fan runs, but compressor will not start.
Approach-Check the compressor voltage (115 VAC).
• If voltage is present, then a defective capacitor or compressor exists.
WARNING—Mechanical Hazard. Keep fingers, loose clothing, etc. away when working on compressor.
• If voltage is not present, then a defective wire harness or PC board exists.
Type III- The unit is operating and continues to cycle, but has low oxygen concentration.
Approach-Check cycle times.
• If cycle times are shorter than normal, check for:
defective sieve beds
• If cycle times are longer than normal, check for:
occluded filters
system leaks
defective compressor
malfunctioning sieve bed check valves
NOTE – Check for leaks using a certified leak detection solution. 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.
• If cycle times are normal, check for an oxygen leak:
top of the sieve beds
accumulator tank
pressure regulator
flow meter
final bacteria filter
outlet port
• If cycle times are normal and no oxygen leaks exist, then connect the pressure-vacuum gauges and look for proper purging
action. If no purge action, troubleshoot purge valve.
Check pilot pressure; if pressure falls below 19 PSI or 130 kPa, check for pilot pressure leaks. If there are no leaks,
replace manifold.
T R O U B L E S H O O T I N G
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