Cooling Systems - Pressure Relief Valves

High Performance Marine Water Pressure Relief Valve

This high performance pressure relief valve system was specifically designed for the highest of performance applications where high speeds and high water pressure run hand in hand. Extensive testing in boats with speeds in excess of 170MPH have proven this design to be the ultimate answer to solving the issues of bleeding off high volumes of water. The problem with standard pressure valves is that they can reduce pressure spikes but they cannot move volumes of water. Hi performance marine applications need to move massive volumes of water. The nearly 2" stainless steel valve is larger and more capable than any fluid control system available today. Besides the ability to move massive distribution of water this valve provides precision adjustable water control. Water control is designed or set to open at a predetermined set pressure to protect against excessive pressure in the engine block, cooling system, and sea strainer. 

High Performance Marine Water Pressure Relief Valve Rebuild Kit

This kit includes the o-rings and snap rings needed to rebuild a 125-5003 HP Pressure Relief Valve. 

This has to be one of the coolest and simplest stream lined inventions to come along in recent times. High water pressure spikes plague numerous boats and cause catastrophic engine damage. Until now your only option was an independent pressure relief valve that you then had to plumb to a water dump to discharge the water. Thanks to the Hardin Marine team they have taken the best high flow water valve design and integrated it into a common water dump.

These dumps feature a sleek design as well as unique wrench flats machined into the body aiding in assembly during a one person installation. Constructed from 316L stainless steel. This model provides a 1/2 NPT female thread allowing for any arrangement of possible fitting and hose connections. The unit features a stainless tulip style valve that is spring loaded. The units come preset at approximately 10psi.

• 1-7/16" Flange Diameter
• 1/4" Flange Height 
• 1-1/8" Shaft Outside Diameter
• 3" Overall Length
• 1/2" NPT Internal Thread
• Pre-set at Aprox. 10lb Pressure Relief, not adjustable.
• Approx. Flow Rate (gallons per minute) 10 psi=7 GPM, 15 psi= 13 GPM, 20 psi=19 GPM

This has to be one of the coolest and simplest stream lined inventions to come along in recent times. High water pressure spikes plague numerous boats and cause catastrophic engine damage. Until now your only option was an independent pressure relief valve that you then had to plumb to a water dump to discharge the water. Thanks to the Hardin Marine team they have taken the best high flow water valve design and integrated it into a common water dump.

These dumps feature a sleek design as well as unique wrench flats machined into the body aiding in assembly during a one person installation. Constructed from 316L stainless steel. This model provides a 3/4 NPT female thread allowing for any arrangement of possible fitting and hose connections. The unit features a stainless tulip style valve that is spring loaded. The units come preset at approximately 10psi.

• 1-3/4" Flange Diameter
• 1/4" Flange Height 
• 1-1/4" Shaft Outside Diameter
• 4" Overall Length
• 3/4" NPT Internal Thread
• Pre-set at Aprox. 10lb Pressure Relief
• Approx. Flow Rate (gallons per minute) 10 psi=7 GPM, 15 psi= 13 GPM, 20 psi=19 GPM

For use with plumbing outlet 150-5000 Water Pressure Relief Kit to dump overboard. Includes:

• One Black Anodized 1/2" NPT to -8 AN Adapter
• One Straight and one 90 Degree Black Anodized -8 AN Hose Fittings
• Polished Billet Aluminum -8 AN Water Dump
• Three feet of -8 AN Premium Water Hose

For use with plumbing outlet 150-5000 Water Pressure Relief Kit to dump overboard. Includes:

• Brass 1/2" NPT x 5/8" Hose Fitting
• Plastic 5/8" Hose Water Dump
• Two Stainless Steel Hose Clamps
• Three feet of 5/8" Water Hose

Jet Drive Water Pressure Relief Kit

The kit from Pack-A-Jet will come with a brass pressure relief valve with 1/2" npt bypass outlet and a stainless steel extension tube for easy installation. Direct fit to the Berkeley models 12JC and 12JG with 3/8" NPT water inlet, but can be used on other models as well as long as they have a 3/8"NPT water inlet on the inside of the boat. Will NOT work on 12JE model or similar pumps where the water inlet is on the outside of the boat. In that case you'll want to buy a pressure relief valve only and a simple T fitting to adapt to the existing inlet tube.

The pressure relief valve opens at app. 12 to 15 psi to move excess water overboard.
Optional hose kits are available see related products below.

Adjustable  Water Pressure Relief Valve 1/2" NPT

This spring loaded adjustable water pressure relief valve is perfect for bleeding off excess engine water pressure caused by pressure spikes in an engines cooling system.  water flows freely when water pressure exceeds the set designated pressure.  Keep high pressure spikes from damaging your engine. With the appropriate adapters can be used as an alternative to Mercury #863208A3.

Adjustable from 7-25 PSI. Flow rate: 1.5 GPM at 10 PSI, 5 GPM at 25 PSI. 

Adjustable  Water Pressure Relief Valve 3/4" NPT Male Port, 1/2" NPT Female Port

This spring loaded adjustable water pressure relief valve is perfect for bleeding off excess engine water pressure caused by pressure spikes in an engines cooling system.  water flows freely when water pressure exceeds the set designated pressure.  Keep high pressure spikes from damaging your engine.

Adjustable from 7-25 PSI. Flow rate: 1.5 GPM at 10 PSI, 5 GPM at 25 PSI. 

1-1/4" Pressure Relief Valve Fitting For Inline Use, 1/2" NPT

This valve should be used in conjunction with the 128-5000 pop off valve.