Installation Guide

Verify Pump Model and Specifications

• Confirm pump model: PA200S, PA200C, PA300S, or PA300C
• Note inlet/outlet port size: PA200S/C = 2″ NPT, PA300S/C = 3″ NPT
• Verify maximum operating pressure: 100 PSI (relief valve must be set below this)
• Check pump weight: PA300S = 173 lbs, PA300C = 165 lbs, PA200S = 114 lbs
• Confirm rotation direction needed for your application (CW or CCW)

Motor and Drive Specifications

• Verify motor horsepower: 2″ pump up to 5.7 HP at 100 PSI, 3″ pump up to 13.4 HP at 100 PSI (see engineering data)
• Confirm motor speed: 2″ pump operates at 190 RPM, 3″ pump at 280 RPM
• Check coupling: Ensure flexible coupling suitable for your drive
• Verify electrical connection and motor nameplate match your power supply

Piping and Accessories

• Relief valve: NOT included — customer must supply. Set to 10–15 PSI above max operating pressure.
• Suction strainer: 50–150 micron recommended
• Discharge piping: NPT schedule 40 steel pipe or equivalent
• Inlet piping: One size larger than pump inlet (3″ for PA200, 4″ for PA300) to minimize restriction
• Pressure gauge: Optional but recommended for monitoring

Fluid Compatibility

• Confirm your fluid is compatible with nitrile rubber gears (standard)
• If using EPDM, urethane, or Viton gears, note gear material for chemical compatibility
• Verify fluid viscosity: Higher viscosity fluids may require lower RPM
• Check temperature rating: Nitrile gears rated to 240°F standard

Inlet (Suction) Line

• Pipe size: One size LARGER than pump inlet port (PA200 = 3″, PA300 = 4″)
• Minimize restrictions: Avoid excessive elbows and valves; use long radius bends if needed
• Avoid air leaks: All connections must be airtight. Use thread sealant on all NPT connections.
• Flooded suction preferred: For initial startup, position the suction source higher than the pump inlet. This ensures the pump chamber is full of fluid before startup.
• Strainer requirement: Install a 50–150 micron inlet strainer upstream of the pump to prevent particle damage to gears, seals, and bearings
• Support the line: Secure piping to prevent vibration and stress on pump ports

Discharge (Outlet) Line

• Pipe size: Match pump outlet (PA200 = 2″ NPT, PA300 = 3″ NPT) or one size smaller if needed
• Relief valve placement: Install relief valve immediately after discharge, before any long runs of piping. This protects the pump from overpressure.
• Minimize backpressure: Avoid excessive discharge line restrictions that create backpressure and reduce flow
• Support the line: Secure discharge piping to prevent vibration and stress
• Slope for gravity drain: If possible, slope discharge line downward to tank to promote drainage when pump is off

Relief Valve (MANDATORY)

• Required: A mechanical relief valve is MANDATORY. The pump will not stop building pressure on its own.
• Set point: Adjust relief valve to open at 10–15 PSI ABOVE your normal operating pressure, but never above 100 PSI (pump maximum)
• Proper sizing: Relief valve capacity must match or exceed the pump’s maximum flow at the set pressure
• Cracking pressure test: Before startup, test the relief valve on a bench to confirm it opens at the desired pressure
• Bypass return: Valve must return excess flow to tank to prevent pressure damage

Coupling Selection

• Flexible coupling required: Use a flexible jaw, disc, or elastomeric coupling to absorb misalignment and reduce vibration transmission
• Coupling torque rating: Ensure coupling torque capacity exceeds the maximum motor torque at the operating speed
• Coupling guards: Install a guard around the coupling per OSHA requirements for safety

Shaft Alignment

• Parallel alignment: Motor and pump shafts must be parallel. Misalignment causes excessive bearing loads and seal wear.
• Angularity tolerance: Keep angular error below 0.05° (less than 0.1 mm at 1 meter) for best results
• Offset tolerance: Axial offset should not exceed 1 mm for flexible couplings
• Laser alignment recommended: For critical applications, use laser alignment tools to verify precision
• Recheck after startup: Thermal expansion may change alignment; recheck after running for 30 minutes

Coupling Installation

• Slide coupling halves onto motor and pump shafts with minimal force
• Center the coupling hub on each shaft (equal overhang on both sides)
• Apply thread sealant (Loctite 222 or equivalent) to set screw threads
• Tighten set screws evenly in a crossing pattern (similar to wheel lug nuts)
• Verify coupling is secure and cannot rotate or slide on the shafts
• Rotate both shafts by hand to ensure smooth, free rotation without binding

How to Check Rotation

1. No product in system yet. Do not prime the pump for this test.
2. Look at the inlet side of the pump (facing the port opening)
3. Slowly rotate the coupling by hand in the direction the motor will turn during operation
4. Observe the gears inside: If rotating clockwise (CW), the gears will appear to roll toward the inlet port, as if drawing product in. This is correct.
5. For counterclockwise (CCW): If the gears appear to roll away from the inlet port, rotation is reversed (incorrect for most applications — see notes below)

Correct vs. Incorrect Rotation

• Correct (CW): Looking at inlet side, gears roll toward inlet port — pump will draw fluid in and prime normally
• Incorrect (CCW): Looking at inlet side, gears roll away from inlet port — pump will not prime and may be damaged. Reverse immediately.

How to Reverse Rotation

If the pump is rotating in the wrong direction, choose one:

• Swap motor leads: Reverse two of the three motor power leads (AC motors) or reverse polarity (DC motors)
• Rotate the coupling 180°: Remove and reinstall the coupling rotated 180° on one shaft (if not keyed)
• Re-verify: After reversing, manually rotate by hand again to confirm correct CW direction

Pre-Startup Verification

• Relief valve installed and tested (cracking pressure verified)
• Suction line fully connected and sealed; no air leaks
• Discharge line connected and relief valve bypass line returns to tank
• Coupling alignment verified and set screws tight
• Rotation direction verified (CW when looking at inlet)
• Pump and motor grounded per electrical code

Flooded Suction Priming (RECOMMENDED)

This is the preferred method for first startup:

1. Position the suction source (tank, barrel) HIGHER than the pump inlet port. Gravity will keep the inlet line and pump chamber full of fluid.
2. Fill the inlet line and pump chamber with fluid via the inlet port (use a funnel if needed). This eliminates air trapped in the pump.
3. Open the suction valve slowly to let fluid enter the pump chamber
4. Close any air vent on the pump discharge (if equipped) to prevent air escape
5. Start the motor and run at LOW SPEED (if variable speed) for 30–60 seconds
6. Monitor discharge: Fluid should flow smoothly without bubbles or sputtering

Gravity Priming (If Flooded Suction Not Possible)

1. Fill the pump chamber and inlet line with fluid manually (use a funnel or gravity from a bucket)
2. With the pump chamber full, start the motor briefly (1–2 seconds)
3. Watch the discharge: If fluid flows, the pump is primed and can run normally
4. If discharge is sputtering or air-filled, stop, refill the inlet line, and try again
5. Never run the pump DRY; this damages the gears and seals

Startup Sequence

1. Confirm relief valve is set and tested.
2. Start the motor at LOW SPEED (if variable speed drive available). Gradual speed increase prevents shock loading on seals and bearings.
3. Listen for normal operation: No grinding, squealing, or loud vibration. A slight humming is normal.
4. Watch discharge flow: Fluid should flow smoothly. Initial sputtering (air bubbles) should clear within 30–60 seconds.
5. Monitor pressure: Pressure should rise gradually as the system loads. Relief valve should not open unless a load restricts flow.
6. Gradually increase speed over 1–2 minutes to full operating RPM. Abrupt speed increase can shock the system.
7. Run at full speed for 5–10 minutes:Check for leaks, abnormal noise, or vibration. Temperature should be moderate (not hot).
8. Verify relief valve opens if there is backpressure (discharge blocked). It should crack open smoothly without chattering.

Common Startup Issues

• Pump won’t prime (no discharge flow): Check for air leaks in suction line, verify suction strainer is not clogged, and confirm rotation is correct (CW at inlet).
• Discharge sputters with air bubbles: This is normal for the first 30–60 seconds. If sputtering continues, there is likely an air leak in the inlet line or suction is restricted.
• Pump vibrates or makes grinding noise: Stop immediately. Check coupling alignment and verify gears can rotate freely by hand. Do not operate until the problem is identified and fixed.
• Relief valve chatters: This indicates instability. Verify relief valve is properly sized for the flow and pressure; valve may need adjustment or replacement.
• Pump gets hot quickly: Verify the relief valve is set correctly. If relief is constantly flowing, heat builds up. Reduce backpressure or adjust relief set point downward.

Relief Valve Selection

• Type: Pilot-operated or direct-acting mechanical relief valve (NOT an electronic solenoid valve)
• Port size: Match pump discharge port (PA200 = 2″ NPT, PA300 = 3″ NPT)
• Flow rating: Relief valve capacity must equal or exceed pump flow at full speed and maximum backpressure
  • PA200 at 190 RPM = up to 69 GPM (see performance data)
  • PA300 at 280 RPM = up to 158 GPM (see performance data)
• Pressure rating: Minimum 150 PSI rated (pump max is 100 PSI, but valve should have headroom)
• Fluid compatibility: Ensure valve seals are compatible with your fluid (standard Viton seals work with most fluids)

Relief Valve Installation

• Mount relief valve immediately after pump discharge, before any long runs of piping
• Relief bypass line must return to suction tank (NOT to a high-pressure discharge line)
• Use NPT thread sealant on all pipe connections
• Keep relief valve outlet line as short as possible to minimize backpressure
• If relief outlet is submerged in tank, keep submersion depth minimal to avoid backpressure

Relief Valve Adjustment & Testing

1. Bench test (before installation): Clamp the valve in a vice and apply pressure via a hand pump or compressed air. Verify it opens at the desired cracking pressure.
2. Set point: Adjust the relief valve to open 10–15 PSI ABOVE your maximum expected operating pressure, but NEVER above 100 PSI (pump rated maximum)
   • Example: If your system normally runs at 60 PSI, set relief to 70–75 PSI
   • Example: If your system runs at 95 PSI (near pump max), set relief to 100 PSI
3. Cracking behavior: Relief should open smoothly and continuously. If it chatters, the setting is too close to normal operating pressure.
4. Field verification: After startup, operate the pump with backpressure (partially blocked discharge) and verify relief opens at the set pressure (use a pressure gauge).
5. Annual inspection: Relief valves can drift or get stuck with buildup. Inspect and re-test annually.

Lubrication Schedule

Your pump has 8 grease zerk fittings (4 seal cavities, 4 bearings). Follow a regular lubrication program:

• Apply NLGI #2 grease every 250 operating hours (or monthly, whichever comes first)
• 7 strokes per fitting with a grease gun
• See Maintenance page for complete details

Pressure & Temperature Monitoring

Track these indicators to catch problems early:

• Discharge pressure: Should be stable and consistent. If pressure spikes or drops unexpectedly, check the relief valve or for blockages.
• Fluid temperature: Should remain moderate (<120°F for most applications). If the pump gets hot, reduce backpressure or check alignment.
• Noise and vibration: Should be quiet and smooth. Grinding, squealing, or vibration indicate a problem.

When to Service or Rebuild

Contact NAPCO or refer to the Repair & Replacement Parts page if:

• Flow rate drops significantly (loss of prime)
• Pressure increases at the same flow (wear or blockage)
• Noise increases or vibration appears
• Fluid leaks from bearing housing seals
• Temperature climbs even after adjusting backpressure