Power Pressure Washer Homepage Contact Us   1-866-858-4982
            
View Cart
Automotive  |  Residential  |  Government - GSA  |  Industrial   RESELLERS: Call for Volume Pricing

HOME > pressure regulator

 

Pressure Washer Unloader Valve - Pressure Regulator

 

 
Pressure Relief Valves
Pressure
Relief Valves
Thermal Relief Valves
Thermal
Relief Valves
Unloader Valves
 

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.

 

Pulsar Unloader Valve
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
8.751-962.0
Pulsar IV
8.704-462.0
Repair Kit – Pulsar 3
9.802-004.0
Repair Kit – Pulsar 280

 

Pressure Regulator - Unloader
unloader valve


Unloader Valves

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
Unloader

MV550 Unloader Valve

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

Ordering Information - FREE SHIPPING

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 & 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
8.904-580.0
w/ Knob
8.704-488.0
Repair Kit
8.712-735.0
Knob Only

 

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

Ordering Information - FREE SHIPPING

MODEL
DESCRIPTION
SPRING COLOR
PRICE
VX3-250
VX S.S. 303 - Unloader Valve 3650 PSI
Blue

 

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

Ordering Information - FREE SHIPPING

MODEL
DESCRIPTION
PRICE
AR21350
VR S.S. 316 - Unloader Valve 2900 PSI

 

Unloader Valves with Pressure Switch
VRT Unloader Valve with Pressure Switch
VRT Unloader Valve


VRT Unloader Valve with Pressure Switch

  • PSI 3650 or 4200
  • Max GPM: 7.8
  • Inlet: 3/8" F
  • Outlet: 3/8" F
  • By-Pass: 2 x 3/8" F
  • Max Temp: 190° F
  • Knob: Yes

Ordering Information - FREE SHIPPING

MODEL
DESCRIPTION
SPRING COLOR
PRICE
VRT3-250PS6
VRT Unloader Valve with Pressure Switch 3650 PSI
Blue
VRT3-310PS6
VRT Unloader Valve with Pressure Switch 4200 PSI
Black

 

Unloader Blocks
Unloader Mounting Block


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 $38.10add to cart
BN-6318 1/2" FPT x 1/2" FPT Brass Unloader Block $39.70add to cart
BN-6784 3/8" FPT x 3/8" FPT Nickel Plated Steel Unloader Block $13.75add to cart
BN-6785 1/2" FPT x 1/2" FPT Nickel Plated Steel Unloader Block $23.80add 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 $4.80add to cart

 

Push-On Hose

Push-On Hose

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

MODEL DESCRIPTION PRICE
18in-push-on 18" x 3/8" Push-On Hose $7.95add to cart

 

See Also

filter pressure washer
Inlet Water Filter


Water Filters
From: $18.70
Protects the system from contaminants in the water

water broom

Large Water Broom

Water Brooms
From:$41.99
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.

 

       
       

 

Can we improve something on this page?

Can this page be improved? Is the information complete and easy to understand? We are always looking to improve our website, so please feel free to give us your comments or suggestions. Thanks for helping us serve you better!

Note : If you would like us to reply, please include an E-mail or Phone Number.
Verification Code:
Please type the code shown in the image:
Ultimate Washer® is a Registered Trademark of the Ultimate Washer, Inc Company. All rights reserved.
Copyright © 2014, www.ultimatewasher.com. All Rights Reserved. Site Map