| NX25-120 & NX25-240 SERIES AC FUEL TRANSFER PUMPS
This Troubleshooting guide provides basic diagnostic assistance. If you have further questions, contact us at 1‑800‑634‑2695 (M‑F 8 AM–6 PM ET), or on the web at “www.fillrite.com”.
Troubleshooting
DANGER!
Disconnect all power prior to performing any service or maintenance. Failure to disconnect the power may cause electrical shock, or unexpected starting
of the motor, resulting in injury or death.
WARNING!
DO NOT open or attempt to repair the motor on your NX25‑120 or NX25‑240 series pump. Opening the motor case can compromise the integrity of
the Explosion Proof construction and will void any existing warranty and certification (UL listing).
Please refer to the warranty policy located on page 2.
Symptom
Cause
Solution
Pump won’t prime
1. Suction line problem
Check suction line for leaks or restrictions; it may be too small in diameter, too long,
or not air tight
2. Vanes sticking
Check vanes for nicks, damage, obstructions, or excess wear; replace as necessary
3. Excessive rotor, vane, rotor cover, or housing wear
Inspect rotor, vanes, rotor cover, and housing for excess wear; replace as necessary
4. Inlet / Outlet blocked
Check pump, hose, nozzle, and filter / strainer for blockage
5. Excessive vertical or horizontal inlet plumbing
Reduce vertical or horizontal distance from pump to liquid
6. Bypass valve stuck
Open valve, remove debris
Low capacity
1. Excessive dirt in screen
Remove and clean screen
2. Suction line problem
Check suction line for leaks or restrictions; it may be too small in diameter, too long,
not air tight, or too low vertically
3. Excessive rotor, vane, rotor cover, or housing wear
Inspect rotor, vanes, rotor cover, and housing for excess wear; replace as necessary
4. Hose or nozzle damage
Replace hose or nozzle
5. Low fluid level
Refill tank
6. Clogged outlet filter
Replace filter
Pump runs slowly
1. Pump in bypass
Normal operation; pump naturally reduces speed in bypass mode
2. Vanes sticking
Check vanes for nicks, damage, obstructions, or excess wear; replace as necessary
3. Motor problem*
Refer to warranty policy
4. Excessive outlet restrictions
Reduce outlet restrictions (e.g. use shorter hose, remove swivel)
Motor stalls / breaker trips
1. Short in wiring
Inspect electrical wiring for shorts and replace as necessary
2. Excess rotor or vane wear
Check vanes for nicks, damage, obstructions, or excess wear; replace as necessary
3. Pump rotor lock‑up*
Clean and inspect rotor and vanes; replace as necessary
4. Debris in pump cavity
Clean debris from pump cavity
Bold text
indicates repairs that are not serviceable by the owner;
please refer to our warranty policy on page 2 for further instructions.
*This condition will shut the motor off.