TM 10-4610-232-12
Table 4-2. Unit Troubleshooting Guide (Continued)
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
Step 5.
Step 6.
Step 7.
Step 8.
Step 9.
Install pump control panel.
NOTE
The following tests should be conducted with the pump head and diaphragm in-
stalled. If pump head is removed it is common for the shaft to hang forward and not
stroke.
NOTE
If the stroke Iength knob does not go to 100, turn it counterclockwise until motion
stops. Remove the yellow cap and loosen hex nut. Reset knob by setting the knob to
point to zero and retightening hex nut.
Reconnect the connector disconnected in step 3 and push the chemical pump “START” pushbutton.
Set the speed knob at 100. Set the stroke knob to 100. Listen to the stroking action. The pump should
pulse between 95 and 110 times per minute. This indicates that the electronic pulser module is work-
ing correctly. Count the number of strokes in 6 seconds and multiply the total by 10 to obtain the
strokes per minute.
(a) If pump strokes faster than 110 times per minute, replace the pulser module (para. 4-36).
Light would stay on almost continuously.
(b) If stroke light stays on, got to step 10.
(c) If stroke light stays off, go to step 7.
(d) If pump strokes slower than 95 times per minute, go to step 9.
Push the CHEMICAL PUMP STOP switch. Remove the pump control panel as in ate 4. Push the
CHEMICAL PUMP START button. Check for 110-120 VAC across terminal 2 and the black incoming
power wire.
If voltage is not present, replace the pump cable (para. 4-36).
Check for 110-120 VAC across pulser terminals 1 and 2,
(a) If no voltage is present, replace the switch (para. 4-36).
(b) If the terminals of the pulser are getting proper voltage, the EPU is stroking, and the stroke
light is off, replace the stroke light (para. 4-36).
(c) If EPU does not stroke with power applied, go to step 9.
Push the CHEMICAL PUMP STOP switch. Disconnect the pump connector. Remove the red wire
from pulser terminals 4 and 6. Power off. Measure resistance across these two wires making sure the
speed knob is set fully clockwise. Resistance should be less than 100 Ohms. Turn speed nob fully
counter clockwise. The resistance should be 1,000,000 Ohms (1 megohm ± 20%).
(a) If the resistance is not correct, replace the potentiometer (para. 4-36).
(b) If the resistance check is not okay, replace the pulser (para. 4-36).
Step 10. Push the CHEMICAL PUMP STOP switch. Disconnect the pump connector. Remove the pump con
trol panel as in step 4. Disconnect yellow EPU wires from pulser terminals 3 and 5. Measure the resis-
tance across the EPU wires. Cold coil (64-72°F) resistance readings should be 42-50 Ohms.
Replace the EPU assembly if readings are other than those listed (para. 4-36).
Step 11. Use an ohmmeter set for high resistance and measure the resistance between either EPU lead and
the green EPU ground lead. Resistance should be infinity.
(a) Replace the EPU assembly if resistance is not infinity (para. 4-36).
(b) Replace the chemical pump if all the preceding checks are satisfactory and the pump will not
run (para. 4-36).
Chemical pumps run but light does not come on (Reference Schematic Diagram FO-1, Sheet 6, schematic
lines 610-611).
Notify direct support maintenance.
4-50
Change 1
2.
