K3.2 Pressure Washer Unloader Valve 4.2–5.5 GPM 400–1450 PSI – OEM Replacement Part
Part Number: 1595
Category: Pressure Washer Parts → Unloader Valves → Flow Actuated Unloader Valves
Type: General Pump K3.2 Flow Actuated Unloader Valve
The General Pump K3.2 Unloader Valve (Part #1595) is a high-quality flow-actuated unloader valve designed for pressure washer systems operating between 4.2 and 5.5 GPM and pressures up to 1,450 PSI. Engineered with General Pump's advanced balanced nozzle and balanced piston technology, the K3.2 provides smooth pressure regulation while minimizing pressure spikes and system stress during bypass operation.
Key Features & Benefits
- Genuine General Pump OEM replacement unloader valve
- Flow-actuated bypass operation
- Designed for 4.2–5.5 GPM systems
- Adjustable pressure range up to 1,450 PSI
- Balanced nozzle technology for smooth bypass operation
- Balanced piston design for precise pressure adjustment
- Eliminates pressure spikes common with traditional unloaders
- No exposed external springs or moving parts
- Brass and stainless steel internal construction
- Flow-through discharge design
- Convenient bypass port configuration
- Dual gauge ports for pressure monitoring
- Helps extend pump and system component life
Technical Specifications
Part Number: 1595
Manufacturer: General Pump
Model: K3.2
Product Type: Flow Actuated Unloader Valve
Flow Range: 4.2 – 5.5 GPM
Pressure Range: 400 – 1,450 PSI
Maximum Pressure: 1,450 PSI
Maximum Temperature: 195°F
Inlet Connection: 3/8" BSP-F
Outlet Connection: 3/8" BSP-M
Bypass Connection: 3/4" BSP-M
Gauge Ports: Dual
Construction: Brass & Stainless Steel Internal Components
Minimum Bypass Requirement: 5%
Repair Kit: Kit 59 (Barens Order #3146)
Dimensions: 5.75" x 3.50" x 2.75"
Weight: 1.7 lbs.
OEM Replacement: Yes
How the Flow Actuated Design Works
The K3.2 utilizes a precision orifice system rather than a traditional check valve.
When the trigger gun is closed:
- Water flow stops or is significantly reduced
- Pressure rises immediately after the internal orifice
- A pressure channel transfers pressure to the piston assembly
- The piston shifts position and activates bypass mode
- Water flow is redirected through the bypass circuit
- Pressure throughout the discharge line is reduced
This design creates smoother system operation while reducing stress on pressure washer components.
Balanced Nozzle Technology
The K3.2 incorporates General Pump's balanced nozzle principle, which provides:
- Reduced pressure during bypass operation
- Elimination of damaging pressure peaks
- Improved trigger response
- Enhanced pressure control
- Reduced wear on pumps and plumbing
- Greater overall system reliability
Common Applications
Pressure Washer Systems
Ideal for:
- Commercial pressure washers
- Equipment wash stations
- Fleet washing systems
- Agricultural cleaning equipment
- Industrial cleaning systems
Specialty Cleaning Equipment
Suitable for:
- Soft wash systems
- Water transfer systems
- Process cleaning equipment
- Custom pressure washer builds
- Mobile cleaning rigs
Performance Benefits
- Precise pressure adjustment
- Reduced pressure fluctuations
- Improved equipment protection
- Consistent cleaning performance
- Extended pump life
- Reliable bypass operation
- Lower maintenance requirements
- Long service life
Signs an Unloader Valve Needs Service
Inspect or rebuild the valve if you notice:
- Pressure instability
- Inconsistent bypass performance
- Reduced cleaning pressure
- Water leakage
- Delayed pressure response
- Excessive wear from long-term operation
Installation Notes
- Install in the discharge line according to manufacturer recommendations.
- Maintain a minimum of 5% bypass flow during operation.
- Verify compatibility with pump flow and pressure ratings.
- Install a pressure gauge using one of the dual gauge ports when possible.
- Adjust operating pressure to system specifications.
- Test bypass function after installation.
Important: Proper bypass flow is required for safe operation and maximum equipment life.
Maintenance Recommendations
- Inspect regularly for leaks and wear.
- Verify pressure settings periodically.
- Maintain adequate bypass circulation.
- Keep inlet filtration systems clean.
- Service with Kit 59 when rebuilding is required.
- Follow manufacturer maintenance intervals.
