Liquid Temperature And Overheating; Pump Vacuum Check; Stopping - Pioneer PB Series Operation & Maintenance Manual

Self-priming centrifugal pump
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Operation
Open all valves in the discharge line and start the power source. Priming is indicated by a
positive reading on the discharge pressure gauge or by a quieter operation. The pump may not
prime immediately because the suction line must first fill with liquid. If the pump fails to
prime within five minutes, stop it and check the suction line for leaks.

Liquid Temperature and Overheating

The maximum liquid temperature for this pump is 160º F (71º C). Do not apply it at a higher
operating temperature.
Overheating can occur if operated with the valves in the suction and/or discharge lines closed.
Operating against closed valves could bring the liquid to a boil, build pressure, and cause the
pump to rupture or explode. If overheating occurs, stop the pump and allow it to cool before
servicing it. Refill the pump casing with cool liquid.
As a safeguard against rupture or explosion due to heat, this pump is equipped with a pressure
relief valve that will open if vapor pressure within the pump casing reaches a critical point. If
overheating does occur, stop the pump immediately and allow it to cool before servicing it.
Approach any overheated pump cautiously. It is recommended that the pressure relief valve
assembly be replaced at each overhaul, or any time the pump casing overheats and activates the
valve.

Pump Vacuum Check

With the pump inoperative, install a vacuum gauge in the system. Make sure the pump is at
least half filled with liquid. Block the suction line and start the pump. At operating speed, the
pump should pull a vacuum of 20 inches of mercury (508.0 mm) or more. If it does not, check
for air leaks at the suction piping gaskets.

STOPPING

Never halt the flow of liquid suddenly. If the liquid being pumped is stopped abruptly,
damaging shock waves can be transmitted to the pump and piping system. Close all connecting
valves slowly.
On engine driven pumps, reduce the throttle speed slowly and allow the engine to idle briefly
before stopping.
Cold Weather Protection
If the pump is to remain idle during below freezing conditions, drain the pump to prevent
damage from freezing. Also, clean out any solids by flushing with a hose.
Bearing Temperature Check
Bearings normally run at higher than ambient temperatures because of heat generated by
friction. Temperatures up to 160º F (71º C) are considered normal for bearings, and they can
operate safely to at least 180º F (82º C).Measure bearing temperature with a contact-type
thermometer.
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Peb series

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