Yamada 711686 Outer Chamber, aluminum for NDP-20
The Yamada 711686 is the genuine replacement outer chamber specified for NDP-20 Series pumps with aluminum wet ends. Two are fitted to a pump, one on each side of the center block.
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 outer chamber
- Material: aluminum
- Fits NDP-20 Series pumps with aluminum wet ends
- 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-20 Series pumps with aluminum wet ends
- 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: 711686
- Part Type: Outer Chamber
- Material: Aluminum
- Fits: NDP-20 Series pumps with aluminum wet ends
- Quantity Used: Two per pump
- Series Port Size: 3/4 in on the NDP-20 Series
- Condition: New
Frequently Asked Questions
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.
Q: Can a cracked plastic chamber be repaired?
It should not be. It is a pressure containing part, and a repair that holds on the bench will open up under pressure and cycling.
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 outer chamber.
CLRMarine
