MDE-4334C Atlas Start-up and Service Manual · April 2008
Page 7-55
Pumping Unit
Hydraulic/Mechanical Components
Servicing the Pressure Control Valve (PCV)
Removing the PCV
Figure 7-28: PCV
The purpose of the PCV is to apply a slight back pressure to the pumping unit, to prevent it
from pumping air through the meter (for example, during a dry tank situation). Meters will
meter air as well as fluid.
Excessive wear or a sticking PCV can cause improper pump performance, including flow loss,
excessive or low discharge pressure, or metering of air under a dry tank condition.
To remove a PCV, proceed as follows:
1
Drain the pumping unit. Refer to
on
.
2
Remove the snap ring. Refer to
.
3
Use a 16 mm socket wrench to turn the valve cover outward or counterclockwise until it is
completely removed.
Note: The cover is held on by bolts and not screwed in.
4
Remove the spring and valve.
5
Use needle nose pliers to remove the valve from the bore.