General Pump 100556 Compact Thermal Relief Valve – 1/4" MPT, 145°F

General Pump 100556 Compact Thermal Relief Valve – 1/4" MPT, 145°F

Protect your pressure washer pump from excessive heat with the General Pump 100556 Compact Thermal Relief Valve. Designed to activate when water temperature reaches approximately 145°F, this valve helps protect your pump from overheating when water is recirculating in bypass mode.

Its compact design and 1/4" 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: 100556

• Type: Thermal Relief Valve

• Inlet: 1/4" Male NPT

• Maximum Temperature: 145°F

• Style: Compact

Applications:

• Cold water pressure washers

• Hot water pressure washers

• Commercial cleaning equipment

• Pressure washer pump systems

• Unloader bypass systems

Features:

• Activates at approximately 145°F

• 1/4" Male NPT connection

• Compact design for installations with limited space

• Helps protect pressure washer pumps from excessive heat

• Automatically relieves overheated bypass water

• Helps extend pump seal and component life

• Genuine General Pump component

What it does:

When a pressure washer is running with the trigger gun closed, the unloader typically places the system into bypass and recirculates water through the pump. If the machine remains in bypass too long, the recirculating water can heat up rapidly.

Once the water temperature reaches approximately 145°F, the thermal relief valve opens and discharges the overheated water. Cooler incoming water can then enter the pump, helping reduce the internal temperature.

Why it matters:

Excessive heat during bypass operation can cause:

• Damaged pump seals and O-rings

• Premature packing wear

• Reduced pump life

• Water leaks

• Costly repairs and unnecessary downtime

A thermal relief valve is a small and inexpensive component that can help prevent much more expensive pressure washer pump repairs.

The General Pump 100556 Compact Thermal Relief Valve is an excellent replacement or preventative-maintenance part for pressure washers requiring a 1/4" MPT, 145°F thermal relief valve.

Not sure whether your pressure washer requires the 1/4" or 3/8" version? Reach out—we'll help you get the right part the first time.