Part Number: ZWD4040G-VRT3-310EZ
Category: Pressure Washer Pumps → Triplex Pumps → Ready-to-Install Pump Assemblies
Type: Comet PMR ZWD4040G-VRT3-310EZ Pump Made Ready with Bypass & Thermal Relief

The Comet PMR ZWD4040G-VRT3-310EZ Pump Made Ready with Bypass & Thermal Relief (Part #6553) is a factory-configured, ready-to-install triplex pressure washer pump assembly engineered for demanding commercial and industrial cleaning applications. Built around the Comet ZWD4040G triplex pump, this complete assembly comes pre-equipped with a VRT3-310EZ unloader valve, integrated bypass, and thermal relief valve, reducing installation time while providing reliable pressure regulation and enhanced pump protection.

Key Features & Benefits

• Genuine Comet ready-to-install pump assembly
• Part Number: 6553
• Built around the Comet ZWD4040G triplex pump
• Pre-installed VRT3-310EZ unloader valve
• Integrated bypass system
• Includes factory-installed thermal relief valve
• Rated for 4.0 GPM at 4,000 PSI
• Operates at 3,400 RPM
• 1-inch hollow shaft for direct engine mounting
• Compatible with engines up to 14.5 HP
• Reduces installation time with factory-installed components
• Helps protect the pump from overheating during bypass operation
• Designed for commercial and industrial pressure washer systems

Technical Specifications

Part Number: 6553

Pump Model: ZWD4040G

Manufacturer: Comet

Product Type: Pump Made Ready Assembly

Maximum Flow Rate: 4.0 GPM

Maximum Pressure: 4,000 PSI

Maximum Speed: 3,400 RPM

Horsepower: 14.5 HP

Shaft Size: 1"

Unloader Valve: VRT3-310EZ

Bypass: Integrated

Thermal Relief Valve: Included

Weight: 24 lbs

OEM Replacement: Yes

Compatible Applications

Designed for use with compatible gas-powered pressure washers utilizing:

• Comet ZWD4040G pump applications
• 1-inch horizontal engine shafts
• Engines up to 14.5 HP
• Commercial pressure washers
• Industrial pressure washers
• Mobile pressure washing equipment
• Equipment repair and replacement projects
• OEM equipment installations

Always verify shaft size, engine horsepower, mounting dimensions, and pressure/flow requirements before installation.

Function of the Pump Made Ready Assembly

The PMR ZWD4040G-VRT3-310EZ assembly helps:

• Deliver up to 4.0 GPM of water flow
• Produce operating pressures up to 4,000 PSI
• Regulate system pressure through the integrated VRT3-310EZ unloader
• Recirculate water during bypass operation
• Protect the pump from excessive heat using the thermal relief valve
• Reduce installation time with a factory-configured assembly
• Provide reliable, high-performance cleaning for demanding pressure washing applications

The combination of the integrated bypass and thermal relief valve helps minimize heat buildup during trigger-off operation, promoting longer pump life and consistent performance.

Common Signs Replacement Is Needed

Replace the pump assembly if you notice:

• Low operating pressure
• Reduced water flow
• Excessive pump noise
• External water or oil leaks
• Pump overheating
• Unloader valve failure
• Bypass system malfunction
• Cracked or damaged pump housing
• Excessive internal wear
• Thermal relief valve malfunction

Replacing the complete pump assembly helps restore pressure washer performance while reducing installation time and equipment downtime.

Installation & Service Notes

• Shut down the pressure washer and relieve all system pressure.
• Verify compatibility with the engine shaft, horsepower, and mounting configuration.
• Install the pump onto the engine according to the manufacturer's specifications.
• Connect the water inlet, high-pressure outlet, and required plumbing.
• Verify the VRT3-310EZ unloader, bypass system, and thermal relief valve are properly installed.
• Prime the pump with water before startup.
• Inspect the system for leaks and verify proper operating pressure after installation.

Important: Never operate the pump without an adequate water supply. Running the pump dry or allowing prolonged bypass operation without a functioning thermal relief valve can significantly reduce pump service life.

Maintenance Recommendations

• Inspect the pump regularly for leaks and abnormal operating noise.
• Check pump oil level and service according to Comet maintenance recommendations.
• Verify proper operation of the VRT3-310EZ unloader valve.
• Inspect the bypass system and thermal relief valve periodically.
• Flush the system after use when pumping dirty or corrosive water.
• Use only genuine OEM Comet replacement parts and approved accessories to maintain maximum performance, reliability, and long service life.