Yamada 715939 Air Chamber, metal for NDP-25 and NDP-32
The Yamada 715939 is a factory air chamber used in NDP-25 and NDP-32 Series pumps. It is a pressure containing part, clamped at its rim by the tie bolts and sealed by the diaphragm bead all the way round.
Chambers fail by erosion, by corrosion and by cracking at the bolt bosses. Abrasive product wears the inside surface thin, particularly opposite the inlet where the flow turns; chemical attack does the same job more evenly. Either way a chamber that has worn thin will eventually split under pressure, and the first sign is usually weeping at the diaphragm bead as the sealing face loses its flatness.
Key Features
- Genuine Yamada replacement air chamber
- Material: metal
- Fits NDP-25 and NDP-32 Series pumps
- Two per pump - one each side of the center block
- Machined sealing face for a positive diaphragm bead seal
- Direct replacement, no modification required
Applications
- NDP-25 and NDP-32 Series pumps
- Rebuilding a pump after abrasive or corrosive service
- Replacing a cracked or eroded chamber
- Restoring a leaking diaphragm bead joint
- Scheduled wet end overhauls
- Marine, industrial and chemical transfer duty
Specifications
- Brand: Yamada
- Manufacturer: Yamada America
- Manufacturer Part Number: 715939
- Part Type: Air Chamber
- Material: Metal
- Fits: NDP-25 and NDP-32 Series pumps
- Quantity Used: Two per pump
- Series Port Size: 1 in on the NDP-25 Series
- Condition: New
Frequently Asked Questions
Q: What torque should the tie bolts be?
Follow the factory figure for the model and tighten opposite bolts in sequence. That is what keeps the clamping load even around the diaphragm bead.
Q: Should both chambers be replaced together?
If one has worn from abrasion, the other has almost certainly worn the same amount. Inspect both and replace as a pair where the duty is abrasive.
Q: How do I know a chamber needs replacing rather than resealing?
Look at the sealing face and the wall thickness. A scored, eroded or dished face will not seal a new diaphragm, and a wall that sounds dull or flexes under hand pressure has lost too much material.
Q: Why does the joint leak after fitting a new diaphragm?
Most often because the chamber sealing face is marked or the tie bolts were tightened unevenly. Both leave a gap the diaphragm bead cannot bridge.
Not sure this is the right part? Send us a Picture of the Pump Plate on your pump and the CLR Marine team will confirm the correct air chamber.
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