Graco 121231 Plug Assembly Cap — Ratio Check
The Graco 121231 Plug Assy Cap Ratio Check is an OEM component designed to securely seal unused ratio-check ports on Graco fluid-handling or proportioner equipment. Built for high-pressure applications, it ensures system integrity, helps prevent contamination, and supports reliable ratio monitoring.
Key Features
- Durable Construction: Precision-machined body resists corrosion and abrasion.
- Leak-Resistant Sealing: High-quality elastomeric O-ring stack for reliable pressure sealing.
- Easy to Install: Hex-drive interface enables torque-controlled installation.
- Maintains System Integrity: Caps off unused ratio-check ports to prevent contamination or leakage.
- Compact Design: Minimal dead volume, ensuring accurate ratio check readings.
Technical Specifications
| Part Number |
121231 |
| Maximum Working Pressure |
Up to ~ 3000 psi (manufacturer-specified systems) :contentReference[oaicite:0]{index=0} |
| Seal Material |
Nitrile (with backup ring) |
| Body Material |
Anodized aluminum alloy :contentReference[oaicite:1]{index=1} |
| Application |
Ratio-check / manifold port sealing on plural-component proportioners |
Compatible Machines
While **Graco does not publicly provide a definitive list** naming every model that uses this part, this plug is generally used in proportioners and two-component systems that support a ratio-check system. Some relevant families and systems include:
- Graco Reactor 2 series (e.g. E-series, H-series, XP-series) :contentReference[oaicite:2]{index=2}
- Graco Electric Proportioners (heated, plural-component systems) per Graco’s parts manual. :contentReference[oaicite:3]{index=3}
- Other Graco fluid-handling or manifold systems that include a ratio-assurance or ratio-check port. :contentReference[oaicite:4]{index=4}
Note: For exact compatibility, consult your system’s parts diagram or manual to verify that part **121231** is the correct plug for the ratio-check port.
Installation Notes
- Ensure the port is clean before installation to avoid damaging the O-ring.
- Tighten using a torque wrench — overtightening can damage the seal, undertightening can cause leaks.
- Inspect periodically for seal wear and replace when necessary to maintain system integrity.
- When servicing, depressurize the system according to the manufacturer’s safety procedure.
Why Choose Genuine Graco?
Using the original Graco part ensures:
- Proper fit and function in critical ratio-check systems.
- Longer service life and seal reliability.
- System integrity and ratio accuracy — non-OEM plugs may compromise performance or leak.
Frequently Asked Questions
Leaving the ratio-check port open may allow contamination, fluid leakage, or pressure loss, which can lead to inaccurate ratio readings or system inefficiencies.
Not necessarily. This plug is intended for systems that have a ratio-check port. Always verify with your system’s parts manual or schematic to ensure compatibility before ordering.
Inspect the seal and body during regular maintenance, especially if you bleed or flush the system often. Replace the O-ring and cap if signs of wear or leakage appear.
