Pulsafeeder Pulsar Shadow - Manual (Page 31)

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close to the pump as possible. With the pump operating at maximum stroke length, gradually
increase the discharge pressure and observe when the HBV starts to operate. The cracking pressure
of the valve must be at least as high as the maximum pressure of the system but no more than 10%
over the pump’s rated pressure. After adjustment tighten the lock nut and reinstall the plastic cover.
Periodic inspection of the valve seat is recommended. If it becomes worn or damaged leakage will
occur regardless of how tightly the valve is adjusted.
7.6 PTP (Push to Purge / Automatic Bleed Valve)
7.6.1 General Description
The PTP (automatic bleed valve) is a gravity-operated ball check valve that automatically removes
gases from the hydraulic system. On each discharge stroke of the pump, hydraulic pressure drives the
ball off the lower seat, expelling any accumulation of gases at the top of the hydraulic system. An
upper seat limits ball travel and flow during each actuation. On each suction stroke, the ball is pre-
positioned by gravity against the lower seat to prevent reentry of gas into the system. When all gas
has been expelled, a small amount of oil will be displaced on each discharge stroke. This oil is
returned by gravity to the hydraulic reservoir. Under normal operating conditions this ongoing
process removes minute, invisible accumulations of gas long before they are visible or detrimental to
pump operation. To accelerate hydraulic startup, pressing the spring-loaded button at the top of the
valve holds the valve momentarily open so that large amounts of gas can be instantly purged. When
the button is released, the valve reverts to normal automatic operation. Bleed valve operation can be
monitored by observing oil flow from the center discharge port through the diagnostic window. Any
accumulation of solids can cause the valve to malfunction.
7.6.2 Removal, Cleaning, & Reinstallation
Use the following procedure to remove, clean & reinstall the PTP (Automatic Bleed Valve)
1. Disconnect the power source to the drive motor.
2. Relieve all pressure from the piping system.
3. Slowly unscrew the valve to gradually relieve any residual hydraulic system pressure.
4. Remove the valve and clean it by soaking in compatible solvent. Valve operation can be confirmed
by blowing air through it in both directions and listening for the “click” sound of ball-seat contact in
both directions.
5. Make sure that the copper gasket is installed at the bottom of the threaded hole in the pump head. It
need not be replaced provided that it is sound and undamaged. The elastomer gasket around the
upper portion of the valve assembly may be likewise re-used.
This valve is not repairable and must be replaced if it continues to malfunction after cleaning.