B&G NP-277 Poly Cup 22029000

B&G NP-277 Polypropylene Plunger Cup (22029000)

The B&G NP-277 Polypropylene Plunger Cup (22029000) is a replacement pump seal for B&G stainless steel hand sprayers. Installed on the pump plunger, this cup seals against the inside of the pump cylinder, allowing each pump stroke to compress air and build pressure inside the sprayer tank.

When the plunger cup becomes worn, cracked, or damaged, air can bypass the seal, making it difficult or impossible to pressurize the sprayer. The NP-277 polypropylene cup also serves as a replacement for the leather-style plunger cups used in older compatible B&G sprayers.

When to Replace the Plunger Cup

Inspect the plunger cup if your B&G sprayer exhibits any of the following symptoms:

• The pump handle moves with unusually little resistance.
• The tank fails to build pressure despite repeated pumping.
• The sprayer requires more pumping than usual to reach operating pressure.
• The existing cup is visibly cracked, distorted, or excessively worn.

Troubleshooting Tip: A dry plunger cup can sometimes cause similar symptoms. Before replacing the cup, inspect it and apply the manufacturer-recommended lubricant to the pump components. If the cup is damaged or the pump still fails to build pressure, replacement may be necessary. Other seals and valves can also cause pressure problems.

How to Replace the B&G NP-277 Plunger Cup

Replacing the plunger cup involves removing and partially disassembling the pump assembly. Refer to the B&G owner's manual for the correct procedure for your sprayer.

1. Depressurize and clean the sprayer. Release all tank pressure, empty the tank, and clean the sprayer according to the chemical manufacturer's instructions before beginning maintenance.
2. Remove the pump assembly. Unscrew and remove the pump assembly from the sprayer tank.
3. Access the plunger cup. Carefully disassemble the pump plunger assembly to expose the cup and its retaining hardware. Note the original arrangement and orientation of the components.
4. Remove the worn cup. Remove the retaining hardware and cup spreader plate as directed in the parts diagram, then slide the old plunger cup off the assembly.
5. Install the replacement. Position the new NP-277 polypropylene cup in the same orientation as the original. Inspect the B&G NP-270 Cup Spreader Plate and replace it if damaged.
6. Lubricate and reassemble. Apply the recommended lubricant, reinstall the retaining components, and reassemble the pump according to the manufacturer's instructions.
7. Test the sprayer. Reinstall the pump assembly and check that the sprayer builds and maintains pressure properly before returning it to service.

Tools: Depending on the pump assembly, basic hand tools such as an appropriately sized wrench or pliers may be needed to remove the retaining hardware. Use the correct tools to avoid damaging the components.

Product Specifications

Maintenance & Related Parts

Keeping the pump assembly clean and properly lubricated helps reduce wear on the plunger cup and pump cylinder. During maintenance, inspect the cup, spreader plate, and other pump seals for damage.

If multiple components are worn, the B&G GD-124 Sprayer Repair Kit may be a more practical option than replacing individual parts.

• B&G NP-270 Cup Spreader Plate
• B&G GD-124 Sprayer Repair Kit
• B&G PO-267 Pump Cylinder (1 Gallon)
• All B&G Sprayer Replacement Parts

Parts Diagram & Owner's Manual

Download B&G Sprayer Parts Breakdown & Owner's Manual (PDF)