Table 4-2. Unit Troubleshooting Guide (Continued)
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
Step 3. Close the airlock valve at the air manifold for the clean/flush tank valve. Disconnect the air tubing to
the valve actuator. Check if the valve stem retracts into the actuator.
(a) If the stem retracts, repair the valve actuator by replacing the air control relay and solenoid
valve (para. 447).
(b) If the stem does not retract, or if it retracts with a jerky motion, replace the actuator (para.
17. Clean/flush tank valve does not open (system shutdown). CLEAN/FLUSH OUTLET valve Iight off (Reference
Schematic Diagram FO-1, Sheet 7, schematic line 735).
Step 1. Check valve for actual position.
(a) Refer to “AUTOMATIC VALVES” general note.
(b) If valve is open refer to valve light does not show correct valve position troubleshooting (mal-
function 19).
Step 2. Disconnect the valve electrical connector P33. Check for 110-120 VAC across pins J33D and J33E. If
there is voltage present, notify direct support maintenance.
CAUTION
Even after closing the block valve in the next step there will be 85 psig (586 kPa) air in
the tubing to the automatic valve. Be careful when disconnecting the tubing at the
block valve. Slowly back off the tubing nut to allow air pressure drainage.
Step 3. Close the air blockvalve at the air manifold for the clean/flush tank valve. Disconnect the air tubing to
the valve actuator. Check if the valve stem retracts into the actuator.
(a) If the stem retracts, repair the valve actuator by replacing the air control relay and solenoid
valve (para. 4-47).
(b) If the stem does not retractor if it retracts with a jerky motion, replace the actuator (para.
18. Clean/flush tank valve does not close (system running normal). Clean/flush valve is not closed when it should
be. Valve light on (Reference Schematic Diagram FO-1, Sheet 7, schematic tine 735).
Step 1.
Step 2.
Step 3.
Step 4.
Step 5.
Step 6.
Check valve for actual position. Refer to “AUTOMATIC VALVES” general note.
If valve is closed, refer to valve light does not show correct valve position troubleshooting (malfunc-
tion 19).
Disconnect the valve electrical connector J33. Check for 110-120 VAC across J33D and J33E. If volt-
age is not present, go to step 6.
Reconnect J33 and check for 110-120 VAC across terminals 4 and 5 on the valve.
If no voltage is present at the terminals, replace the valve cable and connector (para. 4-47).
CAUTION
Even after closing the block valve in the next step there will be 85 psig (586 kPa) air in
the tubing to the automatic valve. Slowly back off the tubing nut at the block valve to
relieve air pressure before removing the air tubing at the automatic valve.
Close the air block valve at the air manifold for the clean/flush valve. Remove the air tubing from the
automatic valve and check that air is being supplied to the valve by opening the air block valve.
If air does not come out the tubing with the air block valve open, find the blockage in the air tubing
and repair it (paras. 4-24 and 4-68).
Check the wiring on the valve for damage or looseness.
(a) Repair any damage to the wiring (para. 4-47).
(b) If the wiring is okay, replace the air control relay and solenoid valve (para. 4-47).
Remove connector P15 (Reference Interconnection Diagram FO-2, Sheet 14) from the control panel
and check for 110-120 VAC across J15H and J15I (Reference Interconnection Diagram FO-2, Sheet
9).
If voltage is not present, notify direct support maintenance.
4-58
Change 1
TM 10-4610-232-12
4-47).
4-47).
