Graco Inc.

Benefits of Thermal Relief

What is Thermal Relief and why is it important?

Oil distribution system temperatures can fluctuate depending on application, location, or even time of day. As the temperature of the oil increases, the pressure within the system increases too as a result of thermal expansion. If not properly relieved, this pressure can cause damage to pumps, meters, or hoses, and may cause spills. 

Graco’s innovative bulit-in Thermal Relief feature on LD pumps protects your equipment and protects your investment. As system pressure builds due to thermal expansion, Graco’s Thermal Relief automatically relieves harmful pressure spikes that could result in equipment damage.

Competitors offer a costly thermal relief kit requiring additional installation. Graco’s Thermal Relief is integrated into the pump itself, and provides pressure relief automatically without the addition of an external kit. Graco recommends a bleed-type regulator, but no more additional plumbing or system modification is necessary!

Thermal Relief Theory of Operation

Whereas traditional double acting reciprocating pumps are able to “dead head” (or stop) on both the up stroke and the down stroke, the LD Pump with Thermal Relief dead heads only on the up stroke. When an LD pump is stopped on its down stroke, the inlet valve relief passage relieves fluid pressure and allows the LD Pump to travel through its down stroke, change over, and “dead head” on the up stroke.

Thermal Relief Tips and Tricks:

  • The air supply does not have to be turned off to enable Thermal Relief activation
  • Thermal Relief will cause the pump to dive on the down stroke when a dispensing valve is closed
  • Thermal Relief can increase the amount of time needed to fully prime the pump.  To minimize this effect, prime the pump before connecting it to an already primed distribution system.

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