Pressure Washer Unloader Valve - Pressure Regulator

 

The pressure cleaner's unloader valve functions as a safety device. Unloader valves control the direction of the flow of water exiting the pump. A positive displacement pump always delivers water, regardless of whether the spray gun is open or closed. When the spray gun is closed, the unloader valve redirects the flow of water back to the inlet side of the pump. This prevents the build up of dangerously high pressure and guards against the failure of component parts. Pressure cleaners are installed with either a Trapped Pressure Unloader or a Flow Actuated Unloader.

Spray guns start, stop, and direct the flow of water from the pressure washer’s nozzle. Squeezing the trigger releases pressure. Releasing the trigger interrupts the flow of water to the nozzle, although the pump continues to run. Without an outlet for releasing this water, pressure would continue to build. A very dangerous situation would result.

The Unloader Valve

Unloader valves function as “traffic cops” and pressure regulator that direct the flow of water in a pressure cleaner system. When water stops flowing from the nozzle of a spray gun, the unloader valve redirects it for a safe pressure outlet. When the cleaner is in “bypass mode,” water that is not released by the spray gun is diverted back to the inlet side of the pressure pump. It then circulates through the pump and back to the inlet side of the unloader valve. Water is once again either released via the spray gun, or redirected to the pump. The process of continued re-cycling of water through the pump is called “cycling.”

  • “Trapped Pressure” unloader valves are the most commonly used. These valves sense and are activated by building pressure at the pump output. Trapped Pressure valves initiate bypass mode in direct response to building pressure in the hose between the pump output and the spray gun. They are often simply called “Pressure” valves. A spike of pressure results when cycling is interrupted and Trapped Pressure valves re-release water to the spray gun. Operators should be prepared for the “kickback” effect on the spray gun or wand to avoid loss of control or injury.
  • “Flow Actuated” unloader valves respond to the interruption of water flow to the nozzle. These valves sense any decrease in flow from the valve to the spray gun and initiate the bypass loop in response. Unlike Trapped Pressure valves, no pressure is trapped, so no “kick back” occurs when water is re-released. With Flow Actuated unloader valves, operators cannot regulate pressure by downsizing the orifice size of nozzles. Flow Actuated valves detect the loss in flow, and react by cycling repeatedly.

Although cycling prevents the dangerous buildup of pressure, added safety concerns arise during bypass mode. Moving parts in the pump create friction and heat which is transferred to the water flow in bypass. Cycling water can quickly be heated to dangerous temperatures as no cool water enters the pump during bypass.

Most pressure cleaner pumps can withstand temperatures of 140º F. At higher temperatures, damage to the pump can occur. Pump packings, plungers, seals, and even the short bypass hose in external bypass systems may be damaged. Thermal Relief Valves offer some protection against excessive heat buildup. They ensure cool water is released to the pump when temperatures exceed 145º F.

Operators are advised to always take care to prevent overheating regardless of the presence of Thermal Relief valves. Pumps should not be allowed to operate in bypass mode for more than 2 to 3 minutes. Squeezing the spray gun trigger always interrupts cycling and introduces new, cool water to the system.

Read article on how to set pressure regulator or unloader valve.

 

Definitions


Safety Relief Valve

The safety relief valve is the designed weak point in the pressure washer. If the unloader malfunctions, the safety relief valve will open and relieve system pressure safely.

EZ Start Adjustable Unloader
EZ Start unloader eliminates pressure in the pump while starting the engine making the unit to start easier; less damaging to starter motors especially on electric start engines.

 

Pressure Regulator - Unloader

VRT3-310EZ Trapped Pressure Unloader Valve
VRT3-310EZ

Trapped Pressure Unloader Valve

The unloader valve is rated up to 4500 PSI at 10.5 GPM. Includes a built-in easy start valve to make starting your engine easier with less pressure restriction. Easily adjust your pressure from 0 to 4500 PSI with a turn of the handle.

  • Maximum Rating: 4,500 PSI at 10.5 GPM
  • Maximum Temperature: 194° F
  • Inlet/Outlet: 3/8" FNPT
  • Bypass: 3/8" FNPT
  • NOTE: The valve has been designed for continuous use at a water temperature of 140°F. It can operate for short periods at a maximum temperature of 195°F.
  • Overall Dimension: 7" x 3.25" x 2"
  • Weight: 1.8 lbs

(Shipping charge of $8.95 will apply on these items if the total order is less than $69.00)

MODEL DESCRIPTION PRICE
VRT3-310EZ (Black Spring) Trapped Pressure Unloader Valve w/ EZ Start 10.5 GPM @ 4500 PSI $71.35add to cart

unloader valve
Unloader Valve

Unloader Valve

Arrowline Unloader, ideal for replacement of any type of pressure regulator, it is inexpensive and problem free.

  • Maximum Rating: 4,350 PSI at 7.8 GPM, 190°F
  • Maximum Temperature: 190° F
  • Inlet/Outlet: 3/8" FNPT
  • Bypass: 3/8" FNPT
  • Weight: 2.1 lbs

(Shipping charge of $8.95 will apply on these items if the total order is less than $69.00)

MODEL DESCRIPTION PRICE
AL607EZ**
Unloader Valve with E-Z Start

* VR2 is the new upgraded version of the unloader valve AL607.
** EZ Start unloader eliminates pressure in the pump while starting the engine making the unit to start easier; less damaging to starter motors especially on electric start engines.

 

unloader valves
MV550 Unloader Valve

MV550 Unloader Valve

Arrowline Unloader, ideal for replacement of any type of pressure regulator, it is inexpensive and problem free.

  • Maximum Rating: 3,600 PSI at 8 GPM, 200°F
  • Inlet/Outlet: 3/8" MNPT
  • Bypass: 1/4" FNPT
  • Weight: 1.65 lbs

(Shipping charge of $8.95 will apply on these items if the total order is less than $69.00)

MODEL DESCRIPTION PRICE
VRT3-250
Unloader Valve MV550

VB7 Regulator - Unloader

VB7 Regulator - Unloader

Fits CAT 4SF pumps and other pumps; 7.8 GPM 3600 PSI max pressure

  • Rated pressure: 3200 PSI
  • 200 °F
  • 3/8" MPT inlet, 1/4" FPT gauge port
  • 3/8" FPT outlet and bypass
  • Wight: 19.7 oz

(Shipping charge of $8.95 will apply on these items if the total order is less than $69.00)

MODEL DESCRIPTION PRICE
8.712-741.0 w/o Knob $89.10add to cart
8.904-580.0 w/ Knob $101.55add to cart
8.704-488.0 Repair Kit $79.75add to cart
8.712-735.0 Knob Only $6.65add to cart

Pulsar Unloader Valve

Pulsar Unloader Valve
  • Pulsar 3 blue rated 3200 PSI - Max 3650 PSI
  • 8 GPM
  • All stainless steel valves
  • Pulsar 3 white rated 1400 PSI -Max 1750 PSI
  • Pressure actuated
  • Forged body
  • Pulsar IV rated 4050 PSI - Max 4350 PSI
  • 3/8" FPT inlet, outlet
  • 195° F
  • Two 3/8" FPT bypass ports

(Shipping charge of $8.95 will apply on these items if the total order is less than $69.00)

MODEL DESCRIPTION PRICE
8.753-014.0 Pulsar 3 (Blue) w/o Knob $65.05add to cart
8.751-962.0 Pulsar IV $93.80add to cart
8.751-961.0 Pulsar IV w/ White Knob $92.35add to cart
8.704-462.0 Repair Kit – Pulsar 3 $49.00add to cart
9.802-004.0 Repair Kit – Pulsar 280 $36.15add to cart

Stainless Steel Unloader Valves

Stainless Steel Unloader Valve
Stainless Steel
Unloader Valve

VX Stainless Steel Unloader Valve
  • PSI: 3650
  • Max GPM: 7.8
  • Inlet: 3/8" F
  • Outlet: 3/8" F
  • By-Pass: 1/4" F
  • Max Temp: 190° F

(Shipping charge of $8.95 will apply on these items if the total order is less than $69.00)

MODEL DESCRIPTION SPRING COLOR PRICE
VX3-250 VX S.S. 303 - Unloader Valve 3650 PSI Blue $347.50add to cart

Stainless Steel Unloader Valve
Stainless Steel
Unloader Valve

VR Stainless Steel Unloader Valve
  • Max GPM: 12
  • Inlet: 3/8" F
  • Outlet: 3/8" M
  • By-Pass: 1/4" F
  • Max Temp: 195°F

(Shipping charge of $8.95 will apply on these items if the total order is less than $69.00)

MODEL DESCRIPTION PRICE
AR21350 VR S.S. 316 - Unloader Valve 2900 PSI $381.40add to cart

Stainless Steel Unloader Valves

Unloader Mounting Block
Stainless Steel
Unloader Valve

Unloader Mounting Blocks

Attach unloader to pressure washer frame to lessen vibration and extend unloader life.

  • Max Pressure: 4000 PSI

(Shipping charge of $8.95 will apply on these items if the total order is less than $69.00)

MODEL DESCRIPTION PRICE
BN-6317 3/8" FPT x 3/8" FPT Brass Unloader Block $47.25add to cart
BN-6318 1/2" FPT x 1/2" FPT Brass Unloader Block $47.25add to cart
BN-6784 3/8" FPT x 3/8" FPT Nickel Plated Steel Unloader Block $19.05add to cart
BN-6785 1/2" FPT x 1/2" FPT Nickel Plated Steel Unloader Block $23.55add to cart

Unloader Bypass Attachments


Use these push-lock barbs and push-on hose to easily create a bypass from your unloader into your water inlet or water tank.

* Longer lengths of push-on hose available, call for custom cut lengths or different size fittings.

1/4" Push-Lock Barb
272-06-04

3/8" Push-Lock Barb
272-06-06

Push-Lock Barbs

(Shipping charge of $8.95 will apply on these items if the total order is less than $69.00)

MODEL DESCRIPTION PRICE
272-06-04 1/4" MNPT x 3/8" Push-Lock Barb $3.95add to cart
272-06-06 3/8" MNPT x 3/8" Push-Lock Barb $4.95add to cart

Unloader Bypass Attachments

Industrial Unloader Valve 7022
7022

Industrial Pressure Washer Pump Pressure Regulator

This Pressure Regulator is designed for single or multiple pump, weep or multi-nozzle systems. This is a flow-thru design easily plumbed into the discharge line or directly onto the discharge head. This regulator maintains set system pressure even when only one of several guns or nozzles is performing or a solenoid valve is open, by-passing the unused flow. The pressure is held in the line during full by-pass and instantly has full pressure, when all guns and nozzle resume operation. 5-10% by-pass is necessary for optimum performance.


  • Min Flow: 2.5 gpm
  • Max Flow: 25 gpm
  • Min Pressure: 500 PSI
  • Max Pressure: 2000 PSI
  • Inlet Port Size: 3/4" NPT(F)
  • Discharge Port Size: 3/4" NPT(F)
  • Bypass Port: 1" NPT(F)
  • Material: Stainless Steel
  • Temperature: 240°F
  • Weight: 5 lbs

(Shipping charge of $8.95 will apply on these items if the total order is less than $69.00)

MODEL DESCRIPTION PRICE
7022 Cat Pump Pressure Regulator 2000 PSI @ 25 GPM $1,069.40add to cart

Industrial Unloader Valve 7590
7590

Industrial Pressure Washer Pump Unloader

This Pressure Sensitive CAT Pump 7590 Regulating Unloader is designed for single or multiple pump, weep or multi-nozzle systems. This unloader maintains set system pressure and goes into by-pass with the release of the trigger or an obstruction downstream. Pressure is held in the line during by-pass with full pressure when the gun is opened or the obstruction cleared and minimal pressure fluctuation with the alternating use of multiple guns. 5-10% by-pass is necessary for optimum performance. Minimum 10 GPM per gun.


  • Max Flow: 52 gpm
  • Min Pressure: 400 psi
  • Max Pressure: 2175 PSI
  • Inlet Port Size: 1
  • Discharge Port Size: 1
  • Material: Brass
  • Temperature: 140°F
  • Weight: 4.46

(Shipping charge of $8.95 will apply on these items if the total order is less than $69.00)

MODEL DESCRIPTION PRICE
7590 Pressure Washer Pump Unloader 2175 PSI @ 52 GPM $673.45add to cart

Industrial Unloader Valve RV2
RV2

Industrial Pressure Washer Pump Regulator

The General Pump RV2 is a Regulating Valve is a 3 way flow-through valve with pneumatically-operated pressure regulator with automatic unloading. It regulates operating pressure of the system by releasing excess volume through the by-pass. It limits pressure in the system to the adjusted value. Unloading eliminates high pressure in the pump. Adjusted pressure can be set ON or OFF by means of the double-acting pneumatic cylinder. Reduces pump start-up load and protects the system from over pressurizations. This model is suitable for automatic systems and remote control. It has an Operating gpm of 48 and a Max psi of 2,900. Its Port Sizes include: Inlet: 1-11 BSPP, Outlet: 3/4-11 BSPP, By-pass: 1-1/4-11 BSPP, and Inlet-Outlet Air Ports: 1/4-19 BSPP.


  • Max Flow: 48 gpm
  • Air Pressure: Min 90 PSI, Max 115 PSI
  • Max Pressure: 2900 PSI
  • Inlet Port Size: 1"-11 BSPP
  • Discharge Port Size: 3/4"-14 BSPP
  • Bypass: 1 1/4"-11 BSPP
  • Material: Brass
  • Temperature: 185°F
  • Weight: 9.9 lbs

(Shipping charge of $8.95 will apply on these items if the total order is less than $69.00)

MODEL DESCRIPTION PRICE
RV2 General Pump Pressure Regulator Valve 2900 PSI @ 48 GPM $1,321.45add to cart

Industrial Unloader Valve 22949
22949

Industrial Pressure Washer Pump Pressure-Actuated Unloader

This is a pressure-actuated unloader that is designed for any pump that fits within the flow and pressure range of the unloader. The unloader regulates the flow in the system and maintains system pressure via an adjustable nut that controls the amount of tension on a pressure spring. When no flow is going out the outlet port, all flow is diverted to the bypass port at virtually no pressure. The unloader is capable of handling one or more shut-off guns and should be run with no bypass (if the full flow from the pump is going through the unloader). It actuates at around 10% above the system pressure.


  • Min Flow: 2.1 GPM
  • Max Flow: 32 GPM
  • Unloader Type: Trapped Pressure
  • Min Pressure: 1600 PSI
  • Max Pressure: 3200 PSI
  • Inlet Port Size: 1" FNPT
  • Discharge Port Size: 1" FNPT
  • Bypass Port: 1" BSP
  • Material: Brass
  • Temperature: 160°F
  • Weight: 17.5 lbs

(Shipping charge of $8.95 will apply on these items if the total order is less than $69.00)

MODEL DESCRIPTION PRICE
22949 Unloader Pressure Actuated 32 GPM @ 3200 PSI (Red Spring)/td> $1,561.80add to cart

Industrial Pressure-Actuated Regulator 22191-D
22191-D

Industrial Pressure Washer Pump Regulator

This is a pressure-actuated regulator that is designed for any that fits within the flow and pressure range of the regulator. The regulator determines the direction of the flow in the system and maintains system pressure via an adjustable nut that controls the amount of tension on a pressure spring. When the water flow stops, it is diverted through the bypass port at virtually no pressure. The regulator is capable of handling one or more shut-off guns and should be run with no bypass (if the full flow from the pump is going through the regulator). It actuates at around 10% above the system pressure.


  • Max Flow: 66 GPM
  • Max Pressure: 4060 PSI
  • Inlet Port Size: BSP-F
  • Discharge Port Size: BSP-F
  • Bypass Port: BSP-M
  • Material: Brass
  • Temperature: 140°F
  • Weight: 4.1 lbs

(Shipping charge of $8.95 will apply on these items if the total order is less than $69.00)

MODEL DESCRIPTION PRICE
22191-D Pressure Washer Pump Regulator 4060 PSI @ 66 GPM $1,448.80add to cart

Industrial Unloader Valve 22950
22950

Industrial Pressure Washer Pump Pressure-Actuated Unloader

This is a pressure-actuated unloader that is designed for any pump that fits within the flow and pressure range of the unloader. The unloader regulates the flow in the system and maintains system pressure via an adjustable nut that controls the amount of tension on a pressure spring. When no flow is going out the outlet port, all flow is diverted to the bypass port at virtually no pressure. The unloader is capable of handling one or more shut-off guns and should be run with no bypass (if the full flow from the pump is going through the unloader). It actuates at around 10% above the system pressure.


  • Min Flow: 2.1 GPM
  • Max Flow: 16 GPM
  • Unloader Type: Trapped Pressure
  • Min Pressure: 3200 PSI
  • Max Pressure: 5800 PSI
  • Inlet Port Size: 1" FNPT
  • Discharge Port Size: 1" FNPT
  • Bypass Port: 1" BSP
  • Material: Brass
  • Temperature: 160°F
  • Weight: 17.5 lbs
  • (Shipping charge of $8.95 will apply on these items if the total order is less than $69.00)

    MODEL DESCRIPTION PRICE
    22950 Unloader Pressure Actuated 16 GPM @ 5800 PSI (Orange Spring) $1,561.80add to cart

Industrial General Pump Unloader Valve
YVB16

Industrial Pressure Washer General Pump Unloader

  • Max Flow: 21 GPM
  • Max Pressure: 8120 PSI
  • Inlet Port Size: 1/2" BSP-F
  • Discharge Port Size: 1/2" BSP-F
  • Bypass Port: 1/2" BSP-F
  • Material: Brass
  • Weight: 7.6 lbs
  • (Shipping charge of $8.95 will apply on these items if the total order is less than $69.00)

    MODEL DESCRIPTION PRICE
    YVB16 Unloader 8120 PSI @ 21 GPM $1,543.70add to cart

Industrial Regulator R1/600
R1/600

Industrial Pressure Washer Pump Regulator

Featuring a lightweight design and hot water capability, this General Pump R1/600A regulating valve maintains a consistent pressure level by releasing extras pressure through the bypass. Simple device that allows you to protect the components of your car wash pressured water system and keep your bays running properly.


  • Max Flow: 21 GPM
  • Max Pressure: 8700 PSI
  • Inlet Port Size: 3/4"-14 BSPP
  • Bypass Port: 3/4"-14 BSPP
  • Material: Brass
  • Temperature: 185°F
  • Weight: 9.3 lbs
  • (Shipping charge of $8.95 will apply on these items if the total order is less than $69.00)

    MODEL DESCRIPTION PRICE
    R1/600 General Pump Pressure Regulating Valve 8700 PSI @ 21 GPM $959.55add to cart

Stainles Steel Unloader Valve
VHP Series Unloader

VHP Series - Unloader Valves

This series of unloader valves diverts water flow into bypass when the trigger gun valve is closed. Unloaders may be designed to respond to either an increase in pressure or a change in flow. The unloader valve may also be used for variable pressure adjustment.


  • Max Flow:21 GPM
  • Max Pressure Range: 6300 PSI - 12800 PSI
  • Inlet Port Size: 1/2"
  • Bypass Port: 1/2"
  • Material: Stainless Steel, Nickel Plated Brass
  • Temperature: 194°F
  • Weight: 2.5lbs
  • (Shipping charge of $8.95 will apply on these items if the total order is less than $69.00)

    MODEL DESCRIPTION PSI GPM INLET / OUTLET PRICE
    VHP70-440 Unloader Valve 6380 21 1/2" $641.25add to cart
    VHP70-700 Unloader Valve 10150 21 1/2" $773.75add to cart
    VHP80-800 Unloader Valve 12800 21 1/2" $664.90add to cart

See Also

Car Wash Booms

Water Filter

From: $19.25
Protects the system from contaminants in the water

Water Broom

Large Water Broom

From:$43.80
High pressure water brooms are powerful, reliable and universal in pressure washing driveways, boat decks, flat surfaces and more. Used to clean flat surfaces quickly, easily and evenly.