Table 4-2. Unit Troubleshooting Guide (Continued)
TEST OR INSPECTION
(b) If the piping leaks, repair the leaks (para. 4-14).
(c) Replace the pump and motor assembly (para. 4-15).
4. Raw water pump requires priming after every shutdown.
Step 1. Check inlet flapper valve housing, pump valves, and piping for tightness.
Tighten/repair loose components or pipe fittings (paras. 4-14 and 4-16).
Step 2. Check for leaks by filling the pump with water.
(a) If the drain valve leaks, replace it (para.4-14).
(b) If the inlet flapper valve leaks, replace it (para.4-16).
(c) If, during inlet flapper replacement, the inlet flapper seat is found to be damaged, replace/repair
the suction flange (para. 4-16).
(d) If there is a leak in the pump shaft area or in the pump casing, replace the pump and motor
assembly (para. 4-15).
(e) Replace inlet flapper valve (para. 4-16).
5. Raw water pump motor hums but doesnt turn.
If the pump has been subjected to freezing conditions, make sure that the pump does
not have ice in it. Warm it thoroughly.
Check ease of rotation of pump. Turn motor fan by hand.
(a) If the motor turns easily, refer to raw water pump electrical troubleshooting.
(b) If the motor turns hard or not at all, replace the pump/motor assembly (para.
6. Raw water pump does not deliver sufficient flow or pressure to operate ROWPU.
Check that operator has correctly performed troubleshooting for this problem.
Check raw water pump rotation. It should be clockwise from the fan end.
If rotation is wrong, rewire motor by interchanging the T1 and T2 leads in the motor junction box (para.
Test raw water pump. Start the pump and let it run until water is flowing out of the ROWPU waste hose.
Close the cartridge filter block valve and read the pressure on the media filter pressure gage.
If the pressure is less than 35 psig (276 kPa) on the black needle, replace the raw water pump and
motor assembly (para. 4-15).
Check cyclone separator performance.
If a heavy stream of water is coming from the waste hoses and the ROWPU shuts down on low
pressure, check hoses and piping for plugging.
Check raw water pump suction hoses for plugging by holding them up to the light and looking for a
Replace any damaged hoses (para. 4-12).
Check cyclone separator vortex finders for plugging.
Remove outlet flanges from separators (para. 4-20). If the gasket shows signs of being compressed
and out of round, replace the gaskets (para. 4-20).
Refer to malfunction 8 under booster pump troubleshooting for additional checks to locate the problem.
If the above checks have not isolated the problem, replace the raw water and pump/motor assembly