Sunrise Medical DeVilbiss 505DZ Service Manual page 17

P A T I E N T A L E R T & D I A G N O S T I C S Y S T E M
Shown below are the failure combinations for the diagnostic service lights D17, D16, and D18 top to
bottom and their respective meanings. NOTE – These lights will illuminate when the unit shuts off and can
be observed when unit is turned off and on again by depressing and releasing switch "S" while unit is
running. It is extremely beneficial to attach pressure-gauges to the sieve bed test points and verify the
following:
HIGH PRESSURE A
POSSIBLE CAUSE:
PURGE VALVE, PC BOARD
(VOLTAGE TO 4-WAY)
LONG CYCLE A
POSSIBLE CAUSE:
LEAK, WORN COMPRESSOR
(VOLTAGE TO 4-WAY)
SHORT CYCLE A
POSSIBLE CAUSE:
SEIVE BEDS, 4-WAY
(VOLTAGE TO 4-WAY)
PC BOARD FAILURE
POSSIBLE CAUSE:
WIRE HARNESS, DEFECTIVE
ELECTRONIC COMPONENT
(VOLTAGE TO 4-WAY)
NOTE – These alarms will illuminate when unit shuts off and can be observed when unit it turned off and on
again by depressing and releasing switch "S" while unit is running.
When a system error is sensed, the compressor will automatically shut off, but the cooling fan will continue to run. The audible
alarm will also sound and the "Service Required" light on the control panel will illuminate.
NOTE—The green "4-way" indicator light on the PC board will illuminate only when the four-way valve is activated. At the same
time the left sieve bed should be pressurizing. When it is off, the right bed should be pressurizing. This light is not considered an
alarm indicator.
IMPORTANT
HIGH PRESSURE
POSSIBLE CAUSE:
SAME AS "A"
(NO 4-WAY VOLTAGE )
LONG CYCLE
POSSIBLE CAUSE:
SAME AS "A"
(NO 4-WAY VOLTAGE )
SHORT CYCLE
POSSIBLE CAUSE:
SAME AS "A"
(NO 4-WAY VOLTAGE )
AN UNEVEN CYCLE TIME
DURING OPERATION
POSSIBLE CAUSE:
LEAK, CROSS PORT VALVE LEAKAGE
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