General Pump 100557 Compact Thermal Relief Valve – 3/8" MPT, 145°F

General Pump 100557 Compact Thermal Relief Valve – 3/8" MPT, 145°F

Protect your pressure washer pump from excessive heat with the General Pump 100557 Compact Thermal Relief Valve. Designed to activate when water temperature reaches approximately 145°F, this valve helps protect the pump from overheating when water is recirculating in bypass mode.

Its compact design and 3/8" Male NPT connection make it an excellent replacement thermal relief valve for many commercial pressure washer pumps and plumbing systems.

Specifications:

• Brand: General Pump

• Part Number: 100557

• Type: Thermal Relief Valve

• Inlet: 3/8" Male NPT

• Maximum Temperature: 145°F

• Style: Compact

Applications:

• Pressure washers

• Hot water pressure washers

• Commercial cleaning equipment

• Pressure washer pump systems

• Unloader bypass systems

Features:

• Activates at approximately 145°F

• 3/8" Male NPT connection

• Compact design for installations with limited space

• Helps protect the pressure washer pump from excessive heat

• Automatically relieves overheated bypass water

• Simple and inexpensive protection for your pump

• Genuine General Pump component

What it does:

When a pressure washer is running with the trigger gun closed, the unloader typically recirculates water through the pump. If the machine remains in bypass too long, that recirculating water can quickly become hot enough to damage pump seals, O-rings, and other components.

The thermal relief valve senses this increase in temperature. At approximately 145°F, the valve opens to discharge the overheated water, allowing cooler incoming water to enter the pump.

Why it matters:

Excessive time in bypass can lead to:

• Overheated pump water

• Damaged seals and O-rings

• Premature pump wear

• Reduced pump life

• Costly repairs and downtime

A thermal relief valve provides an inexpensive additional layer of protection against heat-related pump damage.

The General Pump 100557 Compact Thermal Relief Valve is a smart replacement or preventative-maintenance item for pressure washers using a 3/8" MPT, 145°F thermal relief valve.

Not sure if this is the correct thermal relief valve for your pressure washer? Reach out—we'll help you get the right part the first time.