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5. DIRECTION OF ROTATION AND RELIEF VALVES
There are four types of integral relief valves available. The standard RV, jacketed RV, and double setting RV are
all designated by the letters “RV” in the pump nomenclature. The bi-directional relief valve is designated by the
letters “BV” in the pump nomenclature. Spec numbers are used to help identify some non-standard relief valves.
STANDARD RV
This relief valve is externally adjustable by means of an adjusting screw located in the center of the relief valve
cap. The range of adjustment is approximately 30 psi [207 kPa] to 125 psi [862 kPa]. The actual capability is
dependent on pump speed and liquid viscosity. The settings are for full bypass; that is, all of the fluid is circulating
back to the inlet through the relief valve. The end user must set the relief valve for conditions that exactly match the
application.
JACKETED RV
This relief valve operates in exactly the same manner as the standard RV except that the faceplate is jacketed to
allow provisions for heating or cooling of the relief valve.
DOUBLE SETTING RV
This relief valve is externally adjustable by means of an adjusting screw located in the center of the relief valve
cap. The adjusting screw is fitted with a two position lever to quickly change the relief valve setting. This is
accomplished by moving the lever from one position to the other. The relief valve is set with the lever in the high
pressure position so that the relief valve setting can be quickly reduced by approximately 10 to 30 psi [30 to 207
kPa] by moving the lever from the high pressure position to the low pressure position. Actual drop in pressure
resulting from moving the lever from the high to the low position is dependent on the application.
BI-DIRECTIONAL BV
This relief valve is externally adjustable by means of adjusting screws located in the center of the relief valve caps.
The range of adjustment is approximately 30 psi [207 kPa] to 125 psi [862 kPa]. The actual capability is dependent
on pump speed and liquid viscosity. The settings are for full bypass; that is, all of the fluid is circulating back to the
inlet through the relief valve. The end user must set the relief valves for conditions that exactly match the
application.
DIRECTION OF ROTATION TAGS
Figure 5.1
TYPICAL DIRECTION OF ROTATION TAG
FOUND ON RV STYLE
SINGLE DIRECTION RELIEF VALVES
Figure 5.2
TYPICAL DIRECTION OF ROTATION TAG
FOUND ON BV STYLE
BI-DIRECTION RELIEF VALVES
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