Pulsafeeder Pulsar Shadow - Manual (Page 30)

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9. Inspect the o-ring on the cylinder locating shoulder for nicks or other damage and replace if
necessary, lubricate with PULSAlube 7H.
10. Make certain that the diagnostics seal at the top of the eccentric box flange and the HPV feed port o-
ring at the bottom of the flange are in place (refer to Figure 4).
11. Insert the pumphead onto the eccentric box using the locating pins as a guide.
12. Some compression of the piston return spring will be required in order to start the pumphead retaining
bolts after which the bolts can be tightened to complete installation of the head. Spring compression
will be minimized with the eccentric in the retracted position and the stroke setting at 100%.
13. Reinstall the diaphragm and reagent head.
14. Reinstall the eccentric box drain plug and fill with PULSAlube 7H hydraulic oil.
15. Re-prime the pump.
7.5 Hydraulic Bypass Valve (HBV)
Figure 20
All PULSAR pumps incorporate a Hydraulic Bypass Valve which is an adjustable spring-loaded
valve ported into the hydraulic cavity of the pumphead. The valve is designed to protect the pump
against excessive hydraulic pressure and will not limit or regulate system pressure. The valve is
factory-adjusted for pressure as originally specified, or at 10% above the rated pump pressure.
The HBV is located at the top of the pumphead and any discharge, indicating over pressurization, is
visible at the outer diagnostics port. To adjust the valve, remove the valve’s plastic cover, loosen the
lock-nut, and turn the adjustment screw clockwise (as seen facing the screw) to increase the bypass
pressure and counterclockwise to decrease it. The locking nut must be tightened after adjustment.
Pump damage may occur during a system upset, if the hydraulic bypass pressure is set higher than
10% over the design pressure of the pump. Conversely, if the setting is too low the valve will operate
on each discharge stroke. This results in decreased pumping capacity and will eventually affect the
efficiency of the valve.
To check the hydraulic bypass pressure setting, install a gauge and a regulating valve in the pump
discharge line. The gauge must be between the pump and valve. For convenience, locate the two as