PL-3/8-Thermal Relief Valve 140* F

Name: PL-3/8-Thermal Relief Valve 140* F
Brand: American Pressure Systems
Price: 18.99 USD
Availability: InStock

$1899

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Overview

This is a 3/8" thermal relief valve that protects your pressure washer pump from heat damage. When water trapped inside the pump reaches 140°F — usually from running in bypass with the trigger closed — the valve opens and dumps the hot water, letting cooler water in so the pump doesn't cook itself. It threads into a 3/8" male NPT port on the pump manifold. The body and seal are brass with a stainless steel spring. If a thermal relief valve is leaking, it's either worn out or your water already ran hot enough to trip it, so replacing it is cheap insurance for your pump seals and unloader.

What's included

Opens at 140°F to dump hot water and protect the pump
Prevents pump overheating during bypass operation
3/8" male NPT inlet threads into the pump manifold
Brass body and seal for corrosion resistance
Stainless steel spring for consistent trip pressure
Protects pump seals and unloader from heat damage

Specifications

Inlet: 3/8" (M)NPT
Max Temperature: 140°F
Body Material: Brass
Spring Material: Stainless Steel
Seal Material: Brass
Function: Temperature relief for pressure washer pump

Frequently asked questions

It dumps hot water out of the pump when the internal temperature hits 140°F. When you run a pressure washer in bypass — trigger closed, water recirculating — the trapped water heats up. This valve opens to release it and let cool water in, preventing heat damage to the pump seals and unloader.

A leaking thermal relief valve is either worn out or it's doing its job. If it drips, the valve is likely old and due for replacement, or your water got hot enough to trip it. Either way, replace it to keep your pump protected.

It fits any pump with an open 3/8" male NPT port. The valve threads into a 3/8" NPT connection on the pump manifold. Check that your pump has a matching 3/8" port before ordering.

It opens at 140°F. Once water inside the pump reaches that temperature, the spring releases and the valve discharges the hot water to protect the pump.

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