Cat Pump 5CPQ6221 Triplex Plunger Pump for Demanding High-Pressure Applications
The Cat Pump 5CPQ6221 is a triplex positive displacement plunger pump built for operations that run long hours and cannot afford downtime. It moves up to 6 GPM and handles discharge pressures from 100 to 2000 PSI at 1400 RPM, which puts it in the sweet spot for pressure washing rigs, industrial cleaning stations, misting and cooling systems, water treatment skids, and general plant washdown work. The "Q" in the model number is not cosmetic. It identifies the quieter Cat Pumps design that drops sound output by roughly 6 dBA compared to conventional plunger pumps, a meaningful difference for anyone working near the equipment all day.
Construction is where this pump earns its reputation. The inlet and discharge manifolds are 316 stainless steel, the valve assemblies are 316 stainless steel, and the plungers are solid ceramic running against standard NBR (Buna-N) seals. That combination resists corrosion, scaling, and abrasive wear far better than brass or plated components, so the pump holds its performance through hard water, mild chemistry, and continuous duty cycles. A forged chrome-moly crankshaft, a 0.709 inch stroke, and an oversized crankcase holding 17 ounces of oil keep the drive end cool and stable under sustained load.
At 20 pounds and just under 11.5 inches long, the 5CPQ6221 fits compact skids and mobile units without giving up capability. It accepts belt drive, clutch, flexible coupling, and bellhousing arrangements, so it adapts to whatever prime mover the system already uses. Seal options in FPM, EPDM, and high-temperature configurations extend the working range to 180°F when the application calls for hotter fluid or different chemical compatibility, making this one pump platform that covers a wide range of installations rather than a single narrow use case.
Key Features
- Triplex three-plunger positive displacement design for smooth, low-pulsation flow
- "Q" series engineering reduces operating sound level by approximately 6 dBA
- 316 stainless steel inlet and discharge manifolds resist corrosion and chemical attack
- 316 stainless steel valve assemblies for long service life under continuous duty
- Solid ceramic plungers deliver exceptional wear resistance and seal life
- Forged chrome-moly crankshaft supports sustained high-pressure loading
- Standard NBR (Buna-N) seals and O-rings, with FPM, EPDM, and high-temperature options available
- Large 17 oz crankcase capacity for cooler running and extended oil intervals
- Accepts belt drive, clutch, flexible coupling, and bellhousing drive configurations
- Compact, lightweight footprint suited to skid-mounted and mobile equipment
- Fully rebuildable with readily available seal, valve, and plunger service kits
Applications
- Industrial and commercial pressure washing systems
- Plant and facility washdown equipment
- Vehicle wash and fleet cleaning systems
- Misting, fogging, and evaporative cooling systems
- Reverse osmosis and water treatment feed systems
- Hydrostatic testing equipment
- Agricultural spraying and crop protection systems
- Dust suppression systems
- Surface preparation and paint removal equipment
- Food processing and sanitation cleaning stations
- General water transfer and boosting where high pressure is required
Specifications
- Model: 5CPQ6221
- Pump Type: Triplex positive displacement reciprocating plunger pump
- Flow Rate: 6.0 GPM (23 LPM)
- Discharge Pressure Range: 100 to 2000 PSI (7 to 138 BAR)
- Speed: 1400 RPM
- Inlet Pressure Range: -5 to 60 PSI
- Inlet Ports: Two, 1/2" NPT (F)
- Discharge Ports: Two, 3/8" NPT (F)
- Plunger Diameter: 20 mm
- Stroke: 0.709" (18 mm)
- Shaft Diameter: 0.787" (20 mm)
- Crankcase Oil Capacity: 17 oz (0.50 L)
- Manifolds: 316 Stainless Steel
- Valves: 316 Stainless Steel
- Plungers: Solid Ceramic
- Crankshaft: Forged Chrome-Moly
- Seals: NBR (Buna-N) standard; FPM, EPDM, and HT options
- Maximum Fluid Temperature: 160°F (71°C) standard seals; up to 180°F with optional seals
- Overall Dimensions: 11.47" x 10.0" x 5.75"
- Pump Weight: 20 lbs (8 kg)
- Drive Options: Belt, clutch, flexible coupling, bellhousing
Frequently Asked Questions
Q: What does the "Q" designation mean in the model number 5CPQ6221?
A: The "Q" identifies Cat Pumps' quieter running design, which lowers the pump's sound output by roughly 6 dBA compared to a standard plunger pump of the same class. It is a practical benefit in enclosed rooms, indoor wash bays, and any setting where operators work close to the equipment for extended periods.
Q: What horsepower motor is needed to run the 5CPQ6221 at full pressure?
A: Required horsepower is calculated by multiplying flow in GPM by pressure in PSI and dividing by 1460 for an electric brake horsepower rating. At 6 GPM and 2000 PSI, that works out to roughly 8.2 BHP, so a 10 HP electric motor is a common pairing that leaves adequate margin for startup and continuous operation.
Q: Can the 5CPQ6221 handle heated fluid?
A: With the standard NBR seals the pump is rated to 160°F. Optional FPM, EPDM, and high-temperature seal configurations raise that limit to 180°F. Selecting the correct seal material for both temperature and chemical compatibility is important, since running past the seal rating shortens service life considerably.
Q: How often should the crankcase oil be changed?
A: Cat Pumps recommends an initial oil change after the first 50 hours of break-in operation, then every 500 hours or every three months under normal duty. Systems running continuously, in high ambient heat, or in dusty environments benefit from a shorter interval. The crankcase holds 17 ounces.
Q: Is the 5CPQ6221 field serviceable, or does it need to be replaced when seals wear?
A: It is fully rebuildable. Seal kits, valve kits, plunger assemblies, and complete drive ends are available as service parts, and the pump is designed so the fluid end can be serviced without removing the drive end from the mounting. Routine seal replacement typically restores the pump to full rated performance.
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